Mediastinal hemangiomas: a study of 18 cases with emphasis on the spectrum of morphological features

A study of 18 cases of mediastinal hemangiomas is presented. The patients were eight women and 10 men between the ages of newborn to 74 years. Clinically, the most common symptoms included dyspnea, cough, and chest pain. In one patient the mediastinal hemangioma was associated with another hemangioma in the gastrointestinal tract and presented initially with gastrointestinal bleeding. Four patients were asymptomatic. Anatomically, 14 tumors were located in the anterior mediastinum and four in the posterior mediastinum. Surgical resection was the treatment of choice for all patients. Grossly, the lesions were described as well circumscribed, cystic, hemorrhagic tumors that ranged in size from 2 cm to 20 cm in diameter. Histologically, the tumors were divided into two groups, one showing the features of capillary hemangioma characterized by a lobular and solid growth pattern featuring dilated small vessels and a solid proliferation of endothelial cells and another group showing the features of cavernous hemangioma characterized by large dilated vascular spaces with areas showing interstitial inflammatory changes, fibrosis, and smooth muscle proliferation. A few tumors were characterized by prominent regressive changes, including stromal hyalinization, dystrophic ossification, cystic and perivascular myxoid changes, and extensive fatty overgrowth. Some of the tumors showed extreme cellularity with virtual obliteration of vascular lumina due to compression by tumor cells and focal mitotic activity similar to that observed in cutaneous juvenile hemangiomas. Despite their large size, often infiltrating appearance, and sporadic mitotic activity, follow-up ranging from 1 month to 4 years in 11 patients showed all to be alive and well, thus demonstrating the benign nature of these neoplasms. A discussion of the differential diagnosis and a review of the literature on these rare tumors are presented.

Extramedullary hematopoiesis presenting as posterior mediastinal mass: a study of four cases

We present four cases of extramedullary hematopoiesis occurring in the posterior mediastinum. The patients are two women and two men between the ages of 20 and 87 years. Two patients presented with a history of thalassemia, and one had a history of anemia of undetermined etiology. One patient was asymptomatic, and the posterior mediastinal mass was detected during a routine chest radiographs. Surgical resection of the mass was performed in one patient, whereas a biopsy was performed in the other three. Histologically, all the cases showed the typical features of extramedullary hematopoiesis, namely the presence of numerous lymphocytes admixed with megakaryocytes and red cell precursors. Follow-up information ranging from 2 mo to 3 years showed that all patients are alive and well.

Extramedullary plasmacytomas presenting as mediastinal masses: clinicopathologic study of two cases preceding the onset of multiple myeloma

We present two cases of extramedullary plasmacytoma presenting as a mediastinal mass and preceding the onset of full-blown multiple myeloma. The patients are a 62-year-old woman who presented with progressive dyspnea and left-sided chest pain and a 59-year-old asymptomatic man. In both patients, radiographic studies revealed a posterior and anterior mediastinal mass, respectively. Surgical resection of the tumor was performed in the two cases. The tumors were characterized by a well-circumscribed proliferation of plasma cells surrounded by residual lymph nodal tissue. Immunohistochemical studies on paraffin sections demonstrated lambda light chain restriction. Follow-up in our patients revealed that both of them developed multiple myeloma after 6 months and 2 years, respectively. One patient received treatment with melphalan and prednisone and is currently alive and well without evidence of disease, 2 years after diagnosis. The second patient died 4 years after resection of his tumor with evidence of disease in lumbar spine, skull, and lungs. Extramedullary plasmacytoma presenting as a mediastinal mass may precede the onset of full-blown multiple myeloma; therefore, institution of early systemic therapy in these patients may be of value in preventing further progression of the disease.

Thoracic mycoses from endemic fungi: radiologic-pathologic correlation

The endemic fungi Histoplasma capsulatum, Blastomyces dermatitidis, and Coccidioides immitis are primary human pathogens whose major portal of entry is the respiratory tract. Their clinical manifestations are categorized as acute, chronic or chronic progressive, or disseminated fungal disease. Most acute pulmonary infections are self-limited, and many are asymptomatic. Chronic, progressive, or disseminated disease is much less common and most often occurs in immunocompromised patients. The radiologic manifestations of these disorders are protean. They include interstitial or air-space opacities, solitary or multiple pulmonary nodules, parenchymal masses, cavities, and hilar or mediastinal adenopathy. The diagnosis of a thoracic mycosis requires familiarity with the epidemiology of the fungus in question, the various modes of clinical presentation, and the full spectrum of radiologic manifestations. Although skin and serologic tests can be useful, definitive diagnosis requires culture of the fungus from infected tissue or demonstration of the organism at microscopic examination.

Primary intrapulmonary thymoma. A clinicopathologic and immunohistochemical study of eight cases

We describe eight cases of primary intrapulmonary thymoma occurring in seven women and one man between the ages of 25 and 77 years. Clinically, all patients had initial radiographic findings of a parenchymatous intrapulmonary mass without evidence of mediastinal involvement either radiologically or at surgery. The lesions varied from 0.5 to 10 cm in greatest diameter. Five tumors were located close to the hilum, while the other three were discovered deep within the lung and in subpleural locations. In one case, the lesion appeared to arise endobronchially and infiltrate the surrounding parenchyma. In another case, in addition to the main hilar mass, there were two smaller tumor nodules found deep within the same lung. Histologically, the lesions were characterized by the classic biphasic cellular composition of thymomas, i.e., an admixture in varying proportions of epithelial cells and lymphocytes. Four cases were characterized by sheets of lymphocytes admixed with scattered epithelial cells that were separated by fibrous bands into lobules. Three cases were composed predominantly of sheets of epithelial cells admixed with scattered small lymphocytes and containing prominent perivascular spaces. In two of these cases, focal areas of spindling of the cells were noted. One case was composed predominantly of a spindle cell proliferation with perivascular spaces and numerous small lymphocytes. Immunohistochemical stains for keratin and epithelial membrane antigen in six cases highlighted the epithelial cells scattered against the lymphoid cell background. Seven patients were treated by surgery. In one patient the tumor was deemed inoperable at the time of exploration owing to extensive pleural infiltration and was treated by postoperative radiation; the lesion recurred locally in the pleura 8 years later. Clinical follow-up in three patients after surgical incision showed them to ba alive and well without evidence of disease at 10 months, 2 years, and 8 years, respectively. Two of the patients had been followed clinically for 2 and 4 years following discovery of their lung masses on routine chest radiograph before resection of their tumors. Two patients died of unrelated conditions; in one of them, the lesions had been followed clinically for 6 years before surgery; this patient died 6 months later from coronary artery disease, without evidence of recurrence or metastasis. Our findings suggest that intrapulmonary thymomas are slow-growing tumors that may respond well to surgical resection when confined to the lung. As with their mediastinal counterparts, invasive tumors will require additional treatment for the possibility of recurrence of metastasis.

Thoracic mycoses from opportunistic fungi: radiologic-pathologic correlation

Fungi of the genera Aspergillus, Candida, and Cryptococcus and the class Zygomycetes are the most common causes of thoracic opportunistic mycoses in immunocompromised patients. Candidiasis and zygomycosis usually manifest as severe, often life-threatening, pneumonias. Aspergillus species are commonly implicated as the causative organisms in a broad spectrum of pulmonary disorders, ranging from hypersensitivity lung disease in atopic patients to invasive pneumonia in immunocompromised patients. Cryptococcus neoformans infects both immunologically normal and abnormal patients, with variable clinical and radiologic findings. The diagnosis of an opportunistic mycosis requires familiarity with the epidemiology of the disease, the various modes of clinical presentation, and the full spectrum of radiologic manifestations. Because many of these fungi may normally colonize in the upper respiratory tract, sputum cultures are considered diagnostically unreliable. Instead, definitive diagnosis hinges on either culture of the fungus from infected tissue or demonstration of the organism at microscopic examination.

Malignant thymic neoplasms that may mimic benign conditions

The thymus is a complex, highly specialized organ that is derived from the third and fourth pharyngeal pouches and contains elements that originate from all three germinal layers. As such, it shows certain specific and distinctive reaction patterns to injury that are frequently encountered in a variety of reactive and inflammatory conditions. These reaction patterns, however, can also often be associated with neoplastic diseases arising from this organ, and in some instances, their presence may contribute to obscure the malignant nature of the underlying process. We present a review of the main tumor entities that may be mistaken for benign conditions of the thymus, with emphasis on the three major reaction patterns to injury that may be associated with malignant neoplasms of this organ: prominent cystic changes, stromal fibrosis, and reactive and hyperplastic changes of thymic epithelium. Histologic clues helpful for diagnosis and the differential diagnosis of these lesions are discussed.

Gastrointestinal stromal tumors with prominent myxoid matrix. Clinicopathologic, immunohistochemical, and ultrastructural study of nine cases of a distinctive morphologic variant of myogenic stromal tumor

Nine cases are presented of a distinctive morphologic variant of myogenic gastrointestinal stromal tumor characterized by an unusually prominent myxoid stromal background reminiscent of a neural neoplasm but lacking the immunohistochemical or ultrastructural features of peripheral nerve sheath or ganglionic differentiation. The patients included six women and three men aged 42 to 86 years (mean, 70). The lesions occurred in the stomach (seven cases) and small intestine (two cases) and ranged in size from 2.5 to 9.5 cm. They were described grossly as well circumscribed, unencapsulated, with a prominently myxoid and often cystic cut surface. Histologically, the lesions were composed of a proliferation of round, spindle, or stellate cells embedded in an abundant myxoid stroma. Histochemical stains showed strong positive reaction of the myxoid stromal background with alcian blue at pH 2.5; this staining reaction was abolished by treatment with hyaluronidase, indicating an abundance of connective tissue mucosubstances rich in hyaluronic acid. Immunohistochemical stains showed strong positivity of the tumor cells with vimentin antibodies in all cases and focal weak to moderate positive staining with muscle actin (HHF35) in eight cases and with desmin in two. Stains for keratin, S-100; epithelial membrane antigen, and collagen type IV were uniformly negative. Ultrastructural examination carried out in all cases showed features consistent with those previously described for myogenic gastrointestinal stromal tumors, namely, scattered mitochondria and prominent Golgi apparati, strands of rough endoplasmic reticulum, focal accumulation of intracytoplasmic microfilaments with occasional focal condensations, subplasmalemmal attachment plaques and immature cell junctions, focal extracellular basal lamina material, and surface-oriented micropinocytotic activity. The myxoid changes observed in these tumors may represent a secondary, nonspecific reaction pattern of the tumor cells to some noxious stimulus, or they may be a form of degenerative phenomenon such as that commonly observed in smooth-muscle tumors of the uterus and other sites. Myogenic gastrointestinal stromal tumors with prominent myxoid stroma should be distinguished from benign schwannoma of the stomach and gastrointestinal autonomic nerve tumors. Because of the differences in prognosis for these entities, immunohistochemical and ultrastructural examinations are recommended for the evaluation of gastrointestinal stromal neoplasms with prominent myxoid features.

Mediastinal hemangioma: radiographic and CT features in 14 patients

PURPOSE

To characterize the imaging features of mediastinal hemangioma.

MATERIALS AND METHODS

The authors retrospectively reviewed chest radiographs and computed tomographic (CT) scans from 14 patients with mediastinal hemangioma.

RESULTS

Most mediastinal hemangiomas manifested as well-marginated masses at CT. Three masses had punctate calcifications, and one had phleboliths. Five masses were of heterogeneous attenuation at unenhanced CT. Ten of 11 (91%) hemangiomas were of heterogeneous attenuation at contrast material-enhanced CT, and the following four patterns were observed: central (n = 6, 60%), mixed central and peripheral (n = 2, 20%), peripheral (n = 1, 10%), and nonspecific (n = 1, 10%) increased attenuation. Central increased attenuation was observed more frequently after administration of a bolus of contrast material than after slow infusion.

CONCLUSION

Hemangiomas should be considered in the differential diagnosis of well-marginated mediastinal masses that have heterogeneous attenuation on CT scans, show central enhancement after administration of contrast material or contain punctate calcification.

Malignant smooth muscle tumors presenting as mediastinal soft tissue masses. A clinicopathologic study of 10 cases

BACKGROUND

Smooth muscle tumors presenting as mediastinal soft tissue masses are extremely rare and often are mistaken for other neoplastic conditions.

METHODS

Ten cases of patients with malignant smooth muscle tumors presenting as mediastinal soft tissue masses were studied and correlated with their clinical behavior. Tissues were examined histologically and with immunohistochemical stains in all cases, and by electron microscopy in two cases.

RESULTS

The patients' ages ranged from 26 to 71 years (mean, 56 years); three were women, and seven were men. Three cases were located in the anterior mediastinum and seven in the posterior mediastinum. The patients with anterosuperior mediastinal tumors all presented with signs and symptoms referable to their lesions; the patients with posterior mediastinal masses (with the exception of one) were all asymptomatic. Grossly, the lesions were well circumscribed and unencapsulated, ranging from 6 to 18 cm in greatest dimension and showed a homogeneous, rubbery cut surface with prominent cystic and myxoid areas. The tumors in all patients appeared to arise from the soft tissues within the mediastinum and were unrelated to adjacent structures. In three patients, the tumors compressed and displaced the esophagus without infiltrating its wall, and in one patient, the tumor was found in close proximity, although unattached, to a large vessel. Histologically, the lesions exhibited a spectrum of morphologic appearances that ranged from low grade leiomyosarcoma with mild-to-moderate nuclear atypia and low mitotic activity (< 3/10 high power fields [HPFs]), to high grade tumors with marked nuclear pleomorphism, extensive areas of necrosis, and high mitotic activity (> 10 mitoses/10 HPFs). One case was characterized by a striking epithelioid morphology with large, round cells arranged in small clusters; another was associated with an incidental microscopic focus of thymic seminoma in the adjacent thymus. Immunohistochemical stains in all cases showed positive labeling of the tumor cells with smooth muscle actin, desmin, and vimentin antibodies. Electron microscopy in two cases showed features of smooth muscle differentiation, i.e., spindle cells surrounded by basal lamina material, immature cell junctions, and abundant intracytoplasmic filaments with focal condensations. All patients were treated with surgical excision. On follow-up, three patients with Stage IIIb and IVa tumors died 2-7 years after surgery, and two patients with Stage Ib and IIb were alive and well 4 and 6 years after surgery, respectively.

CONCLUSION

Leiomyosarcomas may arise as primary tumors originating from mediastinal soft tissues in both anterior and posterior compartments. Because of their large size and frequent areas of cystic and myxoid degeneration, they may be confused histologically with neural or other neoplasms. As with their counterparts in other soft tissue locations, histologic grade and clinical stage are the most useful parameters for assessing prognosis.

Malignant smooth muscle tumors presenting as mediastinal soft tissue masses. A clinicopathologic study of 10 cases

BACKGROUND

Smooth muscle tumors presenting as mediastinal soft tissue masses are extremely rare and often are mistaken for other neoplastic conditions.

METHODS

Ten cases of patients with malignant smooth muscle tumors presenting as mediastinal soft tissue masses were studied and correlated with their clinical behavior. Tissues were examined histologically and with immunohistochemical stains in all cases, and by electron microscopy in two cases.

RESULTS

The patients' ages ranged from 26 to 71 years (mean, 56 years); three were women, and seven were men. Three cases were located in the anterior mediastinum and seven in the posterior mediastinum. The patients with anterosuperior mediastinal tumors all presented with signs and symptoms referable to their lesions; the patients with posterior mediastinal masses (with the exception of one) were all asymptomatic. Grossly, the lesions were well circumscribed and unencapsulated, ranging from 6 to 18 cm in greatest dimension and showed a homogeneous, rubbery cut surface with prominent cystic and myxoid areas. The tumors in all patients appeared to arise from the soft tissues within the mediastinum and were unrelated to adjacent structures. In three patients, the tumors compressed and displaced the esophagus without infiltrating its wall, and in one patient, the tumor was found in close proximity, although unattached, to a large vessel. Histologically, the lesions exhibited a spectrum of morphologic appearances that ranged from low grade leiomyosarcoma with mild-to-moderate nuclear atypia and low mitotic activity (< 3/10 high power fields [HPFs]), to high grade tumors with marked nuclear pleomorphism, extensive areas of necrosis, and high mitotic activity (> 10 mitoses/10 HPFs). One case was characterized by a striking epithelioid morphology with large, round cells arranged in small clusters; another was associated with an incidental microscopic focus of thymic seminoma in the adjacent thymus. Immunohistochemical stains in all cases showed positive labeling of the tumor cells with smooth muscle actin, desmin, and vimentin antibodies. Electron microscopy in two cases showed features of smooth muscle differentiation, i.e., spindle cells surrounded by basal lamina material, immature cell junctions, and abundant intracytoplasmic filaments with focal condensations. All patients were treated with surgical excision. On follow-up, three patients with Stage IIIb and IVa tumors died 2-7 years after surgery, and two patients with Stage Ib and IIb were alive and well 4 and 6 years after surgery, respectively.

CONCLUSION

Leiomyosarcomas may arise as primary tumors originating from mediastinal soft tissues in both anterior and posterior compartments. Because of their large size and frequent areas of cystic and myxoid degeneration, they may be confused histologically with neural or other neoplasms. As with their counterparts in other soft tissue locations, histologic grade and clinical stage are the most useful parameters for assessing prognosis.

Thymolipoma: analysis of 27 cases

PURPOSE

To characterize the radiologic features of thymolipoma.

MATERIALS AND METHODS

Twenty-seven cases of thymolipoma were reviewed. Clinical, radiologic, and pathologic findings were noted.

RESULTS

The masses occurred in 15 male and 12 female patients (mean age, 26.7 years). All 27 tumors were in the anterior mediastinum; 22 were in the anterior inferior mediastinum. On frontal radiographs, 12 tumors simulated cardiomegaly. On lateral radiographs, 12 tumors draped over the ipsilateral hemidiaphragm, simulating diaphragmatic elevation. Computed tomographic scans (n = 11) demonstrated a mixture of fat and soft-tissue attenuation in 10 tumors corresponding to adipose and thymic elements found at microscopy. Magnetic resonance images (n = 2) demonstrated fat and soft-tissue signal intensity characteristics. Both types of studies showed a connection between tumor and thymus.

CONCLUSION

Thymolipomas are anterior mediastinal masses that may conform to the shape of adjacent structures. The diagnosis is supported by imaging studies that demonstrate fat and soft tissue within the tumor.

Sclerosing hemangioma of the lung. Granulomatous variant

We present a case of granulomatous sclerosing hemangioma of the lung in a 43-year-old white woman in whom a pulmonary nodule was found on a routine chest roentgenogram. Surgical resection of a well-circumscribed pulmonary nodule was performed. Histologically, the tumor showed the typical features of sclerosing hemangioma with the unusual feature of a florid granulomatous reaction. Immunohistochemical studies using antibodies for epithelial membrane antigen decorated the tumoral cells, while factor VIII was positive in the vascular structure. Histochemical stains for microorganisms yielded negative results.

Epithelioid hemangioendothelioma of the anterior mediastinum. Clinicopathologic, immunohistochemical, and ultrastructural analysis of 12 cases

Twelve cases are reported of primary epithelioid hemangioendothelioma of the anterior mediastinum. Patient ages ranged from 19 to 62 years (mean, 49.4); three were women and nine were men. Seven patients presented with symptoms due to compression of surrounding structures; the remainder were asymptomatic and the lesions were discovered on routine chest x-ray films. The tumors measured from 4.5 to 13.5 cm in greatest diameter; they were encapsulated and well-circumscribed in seven cases and locally infiltrative in five. Histologically, a spectrum of features was observed ranging from those classically described for low-grade epithelioid hemangioendothelioma at other locations--including cells with abundant eosinophilic cytoplasm showing prominent vacuolization and intracellular lumen formation, few mitotic figures, and myxoid changes in the stroma--to more pronounced cytologic atypia, increased mitotic activity, and areas of necrosis. Metaplastic bone formation and osteoclast-type giant cells were observed in five cases, and four tumors displayed focally a prominent intravascular papillary endothelial component. Immunohistochemical studies showed positive staining of the neoplastic cells with factor VIII-related antigen and vimentin and focal staining in most cases with Ulex europaeus lectin. Stains for broad-spectrum keratin, CAM-5.2, S-100 protein, CD34, actin, and desmin were negative. Electron microscopic examination in three cases showed features distinctive for epithelioid vascular endothelial cells, including abundant cytoplasmic intermediate filaments, basal lamina material, marked pinocytotic activity, and primitive intracytoplasmic lumen formation. All cases were treated by surgical excision. Follow-up information was available in nine patients; seven patients were alive and well without evidence of disease 2-21 years after diagnosis (mean follow-up, 8 years); one patient had a recurrence after 1 year and died due to complications of surgery, and another patient died after 1 year of undetermined causes. Despite their often ominous clinical, radiological, and pathological features, epithelioid hemangioendotheliomas arising in the anterior mediastinum appear to behave as low-grade malignant neoplasms that may be adequately controlled in most instances by surgery alone.

The spectrum of pathological changes in the lung in children with the acquired immunodeficiency syndrome: an autopsy study of 36 cases

We present the pulmonary findings in 36 autopsies of children affected by the acquired immunodeficiency syndrome (AIDS). Twenty-three patients were male and 13 were female, ranging in age between 3 days and 13 years. Twenty children had human immunodeficiency virus (HIV)-positive parents or parents who were at high risk of exposure (intravenous drug abusers and prostitutes), five had a history of transfusion, and one had a history of renal transplantation and blood transfusion. Clinically, the patients presented with recurrent infections, failure to thrive, hepatosplenomegaly, fever, cough, and/or hemoptysis. Histologically, specific infectious processes were the most common finding (75% of cases), with Pneumocystis carinii pneumonia being the most prevalent type of infection, followed by bacterial pneumonia. Neoplastic conditions and lymphoid interstitial pneumonia were less frequent (approximately 10% of cases). In addition, in approximately 10% of the cases the pulmonary findings were non-specific (ie, pulmonary edema and atelectasis) and probably unrelated to HIV infection. Our findings suggest that specific infectious conditions constitute the most common type of pulmonary pathology in children with AIDS. However, because there is a small percentage of children with nonspecific findings, a transbronchial biopsy is important for proper evaluation before institution of therapy.

Plasma cell-rich thymoma

A thymoma in the anterior mediastinum of a 49-year-old woman was histologically remarkable for the presence of a prominent plasma cell stromal component surrounding the neoplastic epithelial elements. Polyclonal immunoreactivity for kappa and lambda light chains was obtained by immunocytochemical staining of the plasma cells in the stroma. Although no evidence of myasthenia gravis or other type of autoimmune process could be demonstrated at the time of initial diagnosis, a polyclonal hypergammaglobulinemia of unknown cause subsequently developed in the patient. This case may represent an extreme example of aberrant immunologic modulation of the thymus to an autoimmune process with massive hyperplasia of the B-cell compartment of the gland.

Pleomorphic (spindle/giant cell) carcinoma of the lung. A clinicopathologic correlation of 78 cases

BACKGROUND

The authors undertook this study to define the clinical and histologic characteristics of spindle and giant cell carcinomas of the lung and the survival and prognostic features of these tumors.

METHODS

Seventy-eight cases of pleomorphic (spindle and/or giant cell) carcinoma of the lung were studied by light microscopy and immunohistochemistry to establish clinical, gross, and histologic parameters. Follow-up information was obtained from contributing physicians and analyzed by statistical means to determine prognostically significant parameters.

RESULTS

The patient population consisted of 57 men and 21 women (male to female ratio, 2.7 to 1) between the ages of 35 and 83 years (mean, 62 years). Clinically, 58 patients (80%) presented with symptoms including thoracic pain, cough, and hemoptysis, whereas 14 (18%) were asymptomatic. At the time of diagnosis, 41% of the patients had clinical Stage I lesions, 6% Stage II lesions, 39% Stage III lesions, and 12% Stage IV lesions. Histologically, foci of squamous cell carcinoma were present in 8% of the tumors, large cell carcinoma in 25%, and adenocarcinoma in 45%. The remaining 22% of neoplasms were completely spindle and/or giant cell carcinomas. Spindle and giant cell carcinomas were found together in 38% of the patients. In the 69 patients for whom follow-up information was obtained, 53 (77%) died within 7 days to 6 years after diagnosis, with a 23-month mean survival (median, 10 months) (Kaplan-Meier method). There was a significant shortening of survival for patients with tumor size greater than 5 cm, clinical stage greater than 1, and lymph node involvement. The presence of nodal metastases was the most significant single prognostic factor, whereas the presence of squamous or adenocarcinomatous differentiation did not have an impact on length of survival.

CONCLUSIONS

The frequency with which spindle and giant cell carcinomas are found together, their frequent association with other histologic subtypes of lung carcinoma, and the similar clinicopathologic features of these tumors suggest that they are best regarded as one type of lung cancer called pleomorphic carcinoma.

Benign and malignant salivary gland-type mixed tumors of the lung. Clinicopathologic and immunohistochemical study of eight cases

BACKGROUND

Primary lung tumors showing features of salivary gland-type neoplasms are extremely rare.

METHODS

Eight patients with primary lung neoplasms showing light microscopic and immunohistochemical features of salivary gland-type mixed tumors were studied.

RESULTS

The patients were six women and two men, ages 35-69 years (mean, 52.5 years). The tumors ranged from 2 to 16 cm in greatest diameter. In two patients the lesions presented as polypoid endobronchial lesions obstructing the lumen; in another two patients the lesions were found in close proximity or in continuity with a bronchus; in three patients, the lesions presented as peripheral parenchymatous nodules unrelated to a bronchus; and in one patient, the relationship to the bronchus could not be determined. Histologically, the lesions were biphasic, showing admixtures in varying proportions of epithelial elements containing a predominant myoepithelial cell population with a stromal component containing an abundant myxoid or focally chondroid matrix. Immunohistochemical studies showed strong positivity of the cells in the epithelial component with low molecular weight keratins (CAM 5.2), and to a lesser extent with broad spectrum keratin, actin, and vimentin antibodies. The cells also showed variable reactivity in the epithelial and nonepithelial elements with S-100 protein and glial fibrillary acidic protein. Six tumors were grossly and histologically benign; in two patients, the tumors were larger, locally invasive, and showed more atypical histologic features. All patients were treated with surgical excision. On follow-up, of the six patients with histologically benign-appearing tumors, one was alive and well 6 years after surgery; another died 4 years after surgery of a second unrelated malignancy; one died during the immediate postoperative period of myocardial infarction; and three have been lost to follow-up. In the two patients with histologically atypical lesions, the tumors recurred and metastasized after 2 and 3 years, respectively, with one of them leading to death caused by widespread metastases and superior vena cava syndrome.

CONCLUSIONS

Review of the literature and the findings in the current series indicate that salivary gland-type mixed tumors of the lung may present with a spectrum of histologic features and clinical behavior, ranging from benign to frankly malignant, similar to that observed for their salivary gland counterparts. Size of the lesion at the time of presentation, extent of local infiltration, and degree of mitotic activity appear to be the most reliable prognostic features of these tumors.

Mycobacterial spindle-cell pseudotumor of the spleen

A case of spindle-cell pseudotumor of the spleen due to nontuberculous mycobacteria in a patient with acquired immunodeficiency syndrome (AIDS) is described. The patient was a 55-year-old, human immunodeficiency virus-positive Haitian man who died of acute neurologic complications while on treatment for central nervous system toxoplasmosis. At autopsy, an enlarged multinodular spleen was noted. Histologic examination revealed coarse nodules of splenic parenchyma replaced by a dense spindle cell proliferation, admixed with scattered inflammatory cells. Immunostains showed strong cytoplasmic positivity of the spindle cells with MAC 387, HAM 56, and alpha-1-antichymotrypsin antibodies and negative staining for actin, vimentin, and S-100 protein antibodies. Ziehl-Neelsen stains revealed numerous elongated acid-fast bacilli within the cytoplasm of the cells that were occasionally lying free within the interstitium. The organisms also had a strongly positive reaction with antibodies to desmin intermediate filaments. Mycobacterial spindle-cell pseudotumor should be included in the differential diagnosis of conditions affecting the spleen in patients with AIDS.

Rhabdomyosarcomas of the anterior mediastinum: report of four cases unassociated with germ cell, teratomatous, or thymic carcinomatous components

Four cases are presented of primary anterior mediastinal tumors in young adults that were characterized by solid, infiltrative lesions showing histologic and immunohistochemical features of rhabdomyoblastic differentiation. The patients were three men and one woman between 19 and 27 years of age (mean age, 23 years). All patients presented with symptoms referable to their tumors, including cough, chest pain, dyspnea, and left-sided pleural effusion. Grossly and radiographically, the lesions were characterized by their solid, infiltrative appearance. Histologically, two cases corresponded to the solid variant of alveolar rhabdomyosarcoma, one case was an embryonal rhabdomyosarcoma with a predominant spindle cell component, and the remaining case showed the features of a pleomorphic rhabdomyosarcoma. No glandular, epithelial, or other component could be identified in any of the tumors on extensive sampling. Immunohistochemical studies showed positive staining of the tumor cells with actin, desmin, and vimentin antibodies, with focal positivity for myoglobin in three cases and focal positive staining with S-100 protein in one case. Stains for low and high molecular weight keratin, carcinoembryonic antigen, alpha-fetoprotein, human chorionic gonadotropin, placental alkaline phosphatase, leukocyte-common antigen, and neuron-specific enolase were negative. All patients experienced rapid recurrence and metastases within the first 6 months after diagnosis. Three patients died within this period due to their tumors; the fourth patient has been lost to follow-up. Pure primary rhabdomyosarcomas of the anterior mediastinum are highly aggressive neoplasms that should be distinguished from germ cell, teratomatous, or carcinosarcomatous tumors with a focal rhabdomyoblastic component.

Bronchogenic carcinoma: radiologic-pathologic correlation

Bronchogenic carcinoma is the leading cause of death from cancer in men and women in the United States. Although the cause of this malignancy is probably multifactorial, approximately 85% of lung cancer deaths are attributable to cigarette smoking. Patients may present with symptoms of airway obstruction caused by central tumors, symptoms related to direct tumor invasion of surrounding structures, or symptoms produced by distant metastases. There are four major cell types: adenocarcinoma, squamous cell carcinoma, undifferentiated large cell carcinoma, and small cell carcinoma. Adenocarcinoma and undifferentiated large cell carcinoma are generally peripheral lesions manifesting as solitary nodules or masses, whereas squamous cell carcinoma and small cell carcinoma are typically central and may manifest as hilar masses, atelectasis, or pneumonia. The prognosis for patients with bronchogenic carcinoma is poor, with an overall 5-year survival of 10%-15%. In general, patients with squamous cell carcinoma have the best prognosis, those with adenocarcinoma and undifferentiated large cell carcinoma have an intermediate prognosis, and those with small cell carcinoma have the worst prognosis.

Thymofibrolipoma. A histologic variant of thymolipoma

We report two cases of a thymic neoplasm showing abundant fibroconnective tissue with focal areas of fatty tissue. The two patients, a 9-year-old girl and a 32-year-old man, were found to have an anterior mediastinal mass on routine chest roentgenograms. Surgical resection was performed in both cases. Because of the histologic features shown by these neoplasms, we believe that these cases represent a variant of thymolipoma, and we have named it thymofibrolipoma.

Primary adenoid cystic carcinoma of the lung. A clinicopathologic and immunohistochemical study of 16 cases

BACKGROUND

Adenoid cystic carcinoma (ACC) is a rare but distinctive salivary gland-type malignant neoplasm that arises infrequently as a primary tumor in the lung.

METHODS

The clinical and pathologic features in 16 cases of primary ACC of the lung were reviewed, and immunohistochemical stains on paraffin sections were performed in 7 cases.

RESULTS

The patients' ages ranged from 29 to 79 years (mean age, 54 years); 11 were men and 5 were women. Clinically, most patients were seen initially with obstructive symptoms, including cough, wheezing, shortness of breath, and hemoptysis. Eight tumors were in the left lung and eight in the right lung. The lesions were treated by pneumonectomy in seven patients, lobectomy in six, and lobectomy plus chemotherapy in two. One patient was treated with chemotherapy alone after undergoing a diagnostic biopsy that revealed advanced disease. Grossly, most lesions were described as endobronchial and measured from 0.9 to 4.0 cm in greatest dimension; two cases, however, showed poorly circumscribed infiltrative tumors. Histologically, three main growth patterns were identified admixed in various proportions: cribriform (cylindromatous), tubular, and solid. Immunohistochemical study in six of seven cases showed a prominent myoepithelial cell component, as evidenced by immunoreactivity for keratin, actin, and S-100 protein in numerous tumor cells. Clinical follow-up ranging from 2 to 15 years in six patients showed that three were alive and well without evidence of recurrence or metastases at 5, 10, and 12 years, respectively, and three were alive with recurrence at 2, 5, and 15 years, respectively. Three other patients died of unrelated conditions at 2, 7, and 9 years, respectively, after diagnosis. Two patients in the study were seen initially with metastatic spread at the time of initial diagnosis and died 2 months and 1 year later with widespread metastases to lymph nodes, liver, spleen, kidney, and bone despite intensive chemotherapy.

CONCLUSIONS

Disease stage at the time of diagnosis may play an important role in predicting the clinical outcome of patients with these tumors. Despite their generally slow and indolent growth in other locations, ACC arising in the lung may in certain cases be more aggressive.

Endobronchial lipomas: a clinicopathologic study of four cases

Four cases of endobronchial lipomas are presented. The patients were men between 45 and 54 yr of age. Clinically, two of the patients presented with cough and one with shortness of breath. Two lesions were located in the left lower lobe, one in the right upper lobe, and one in the right lower lobe. Because of the clinical suspicion of malignancy, all patients underwent radical surgical procedures; lobectomy was performed in 3 patients, and pneumonectomy in one. Grossly, all the lesions were characterized by well-circumscribed, soft, yellow nodules that ranged in size from 1.2 to 3.0 cm in greatest diameter. Histologically, the tumors resembled lipomas in other locations, i.e., they were composed of mature adipose tissue devoid of atypia. In two cases, prominent spindle cell areas were also present similar to those of spindle cell lipoma. Identification of the lesion by endoscopic and radiologic means may help avoid unnecessary radical surgery. A review of the literature on these unusual lesions is presented along with a discussion of their differential diagnosis.

Total parenteral nutrition: a histopathologic analysis of the liver changes in 20 children

The histologic features of liver biopsies from 20 children treated with total parenteral nutrition (TPN) are presented. All the children received TPN for no less than 2 wk. Conditions that led clinicians to use this form of treatment included prematurity, sepsis, and gastrointestinal surgical procedures. Fourteen children had a history of prematurity; in nine the birth weight was between 640 and 1300 g. Gestational age and birth weight were not available in five and 11 children, respectively. Ten of the 20 children died. Our findings suggest that the morphologic features observed in the liver can be correlated with the duration of TPN. Thus, we propose a time table of hepatic histologic findings beginning with cholestasis and culminating in cirrhosis.

Pulmonary adenofibroma: report of two cases of an unusual type of hamartomatous lesion of the lung

We report two cases of a primary lung tumour characterized by complex gland-like spaces lined by simple cuboidal to columnar epithelium surrounded by a hyalinized spindle-cell fibroblastic proliferation reminiscent of adenofibromas of the female genital tract. The lesions occurred in a 54-year-old woman and a 56-year-old man. The tumours presented clinically as 1-2 cm, solitary 'coin' lesions and were discovered incidentally on routine chest X-rays. Both lesions were treated by lobectomy. One patient is alive and well with no evidence of disease after 8 years; the other died of myocardial infarction 5 years following resection of his tumour without evidence of recurrence. We interpret these lesions as benign hamartomatous growths; their main importance lies in distinguishing them histologically from other types of pulmonary hamartomas, pulmonary blastomas, intrapulmonary solitary fibrous tumours, and metastases from soft tissue and visceral sarcomas.

Mediastinal paragangliomas. A clinicopathologic and immunohistochemical study of 16 cases

BACKGROUND

Paragangliomas of the mediastinum are rare neoplasms. Because of their rarity, the spectrum of morphologic and immunohistochemical features and biologic behavior of these tumors in this location has not been delineated.

METHODS

A retrospective study of 16 cases of mediastinal paragangliomas was undertaken to evaluate their clinicopathologic and immunohistochemical features.

RESULTS

The patients were 10 men and 6 women whose ages ranged from 16-69 years of age (mean, 42.5 years). Twelve tumors were located in the posterior mediastinum, and three tumors were located in the anterior mediastinum. In one case, the exact location of the tumor within the mediastinum was not available. Microscopically, the nesting pattern (zellballen) was the most commonly encountered. Areas of stromal hyalinization were also frequent and were marked in two tumors. In two cases there was a prominent spindle cell component, and two cases showed granular cell changes in the cytoplasm of the tumor cells. Cellular pleomorphism was observed in the majority of cases. Occasional mitoses were seen in a few cases. Immunohistochemical studies in 10 cases showed chromogranin reactivity in 10 of 10 cases, S-100 protein in 9 of 10 cases, leu-enkephalin in 6 of 10 cases, and neurofilament protein in 5 of 10 cases. Keratin was negative in all cases studied. All patients underwent surgical resection of their tumors, and one patient underwent adjuvant radiation therapy. Follow-up information ranging from 1-168 months (mean, 84.5 months) was obtained in 12 patients. Nine patients (75%) were alive and well at last follow-up. In one patient the tumor metastasized to spinal space and bone marrow, and another patient died with metastases to lymph node, lung, and pelvis 14 years after initial diagnosis.

CONCLUSIONS

The only parameter found to correlate with aggressive behavior was the extent of circumscription and/or local infiltration of the tumor at initial resection. No clinical, histologic, or immunohistochemical features were otherwise found to separate aggressive from indolent clinical behavior. Regular follow-up is recommended in these patients due to the potential for these tumors to metastasize.

Sarcomas with combined features of liposarcoma and leiomyosarcoma. Study of two cases of an unusual soft-tissue tumor showing dual lineage differentiation

Two cases are described of a soft-tissue sarcoma characterized histologically by the intimate admixture of areas displaying the features of liposarcoma and leiomyosarcoma. Both cases occurred in men, 70 and 77 years of age. The lesions were located in the left scrotum and abdominal cavity, respectively. Histologically, the lipomatous component in both cases consisted predominantly of well-differentiated liposarcoma with myxoid areas. The smooth-muscle component was characterized by intersecting fascicles of spindle cells displaying nuclear atypicality and scattered mitotic figures; the spindle cells in these areas were strongly immunoreactive with actin and desmin antibodies. The above tumors must be distinguished from angiomyolipoma, spindle-cell lipoma, myolipoma of soft tissue, and more importantly, from "dedifferentiated" liposarcoma. The development of dual lineage differentiation within adipose tissue tumors as exemplified by these two cases may be more prevalent than has been generally recognized, and may require the application of immunohistochemical markers for specific identification of the spindle-cell component.

Granulomatous Pneumocystis carinii in AIDS patients

Seven cases of Pneumocystis carinii pneumonia with granulomatous reaction in patients infected with the human immunodeficiency virus are described. The patients were all adult men between the ages of 32 and 45 years, with different high-risk factors. Clinically, all the patients presented with a history of non-productive cough and shortness of breath. Two of the patients had a past history of pulmonary pneumocystosis. Radiologically, six patients had diffuse pulmonary infiltrates and one nodular pulmonary infiltrate. Transbronchial lung biopsies were obtained in four patients and open lung biopsies in three. All presented a predominant granulomatous reaction composed of epithelioid and multinucleated giant cells. Several other special stains to detect the presence of other microorganisms to account for the granulomatous reaction were negative.

Laryngeal chondrosarcomas

Four cases of laryngeal chondrosarcoma are presented. The patients' ages ranged from 60 to 75 years; one was a man and three were women. Two of the tumors arose in the thyroid cartilage, one in the cricoid cartilage, and one in the left arytenoid cartilage. A rapid fatal course with pulmonary and cerebral metastases was observed for the tumor arising in the arytenoid cartilage that histologically corresponded to a myxoid chondrosarcoma. The other three cases corresponded to low-grade, well-differentiated chondrosarcomas of the hyaline type, and the patients were alive and free of recurrence or metastases 3 to 6 years following total and partial laryngectomy. A review of the literature on the topic and the importance of assessing histologic grade, size, and location in the evaluation of these neoplasms is discussed.

Metastatic mature teratoma in lung following testicular embryonal carcinoma and teratocarcinoma

We report seven cases of metastatic mature teratoma in the lung from testicular teratocarcinoma and embryonal carcinoma. The patients were between 19 and 58 years of age when orchiectomy was performed. The primary tumors each contained a prominent component of embryonal carcinoma as well as mature and immature teratoma in six patients and only embryonal carcinoma in one. In three patients metastatic pulmonary nodules were detected at the time of orchiectomy, and in three others pulmonary metastases occurred 4 and 8 months after orchiectomy. In one patient the interval was 1.5 years; however, chest roentgenography was not performed during that period. All the patients received chemotherapy or radiation therapy prior to removal of the pulmonary metastases. Thoracotomy was performed between 4 months and 9 years after detection of pulmonary metastases on chest roentgenograms. In one patient the procedure consisted of a lobectomy and in another a pneumonectomy. In the remaining five cases excision of the nodules was performed. The pulmonary metastases resected were grossly solitary lesions in five patients and multifocal in two. Microscopically, each tumor consisted entirely of mature teratoma. Cuboidal and mucin-secreting glandular epithelium predominated in the cystic areas; fibroconnective tissue was the predominant feature of the solid areas. In four patients the course has been indolent with no manifestations of the disease after at least 1 year; in two patients no follow-up was obtained; and one patient died, apparently of a septic process. We present a discussion of this interesting and unusual event.

Rhabdomyomatous thymoma

A case of a thymic neoplasm with a prominent rhabdomyomatous component is presented. The patient, a 21-year-old asymptomatic man, had an anterior mediastinal mass found on routine chest radiographs. Surgical resection of an encapsulated anterior mediastinal mass was performed. Histologically, two distinct cell populations were apparent, one epithelial and the other myoid. Immunohistochemical studies using antibodies for keratin decorated the epithelial component of this lesion; antibodies for myoglobin and desmin strongly stained the myoid component.

Mucinous (so-called colloid) carcinomas of lung

We present 24 cases of primary mucinous (so-called colloid) carcinomas of the lung. The patients were between 33 and 81 yr old (median: 57 yr), including 15 men and nine women. The lesions were discovered incidentally on chest X-ray, where they presented in diverse forms. No predilection for a particular lobe or pulmonary segment was observed. The tumors varied from 0.5 to 10 cm in greatest diameter. Grossly, the tumors were poorly circumscribed, soft, tan-to-gray mucoid lesions. Microscopically, they showed intra-alveolar pools of mucin containing small clusters of atypical cells floating in the mucin, and foci of neoplastic columnar epithelium lining scattered alveoli. Seven cases showed areas of solid, well-differentiated malignant glands adjacent to pools of mucin. In two cases, lymph node metastases were found at surgery. Eleven (57%) of 19 patients were alive over a follow-up period ranging from 2 to 192 mo; one of them had metastases to bone and another had intrapulmonary recurrence. Eight patients died with/of their tumors, two of them with known metastases to bone and/or brain, and one with recurrence after 2 yr of initial diagnosis. No follow-up was obtained in five patients. Although the extent of clinical evaluation varied, no other primary neoplasms (i.e., breast, gastrointestinal tract, or other organs where primary mucinous carcinomas are known to occur) were observed. These tumors probably represent a variant of bronchioloalveolar carcinoma and share the prognosis of that neoplasm. However, because of their often bland cytologic features and paucity of malignant cells, they may be difficult to diagnose as neoplasms.

Acinic cell carcinoma of the lung ("Fechner tumor"). A clinicopathologic, immunohistochemical, and ultrastructural study of five cases

The clinical, pathological, immunohistochemical, and ultrastructural features in five cases of primary acinic cell carcinoma of the lung are presented. The patients' ages ranged from 44 to 75 years (mean, 56); four were women and one a man. The lesions were discovered incidentally on routine chest x-ray and ranged from 1.2 to 4 cm in greatest diameter. Three tumors were located in the right middle lobe, one in the right upper lobe, and one in the left upper lobe. In three cases, the lesions presented as asymptomatic subpleural nodules in proximity to secondary bronchi, one case presented as an endobronchial tumor that led to obstructive symptoms, and one case as a well-circumscribed deep parenchymal nodule. Histologically, the tumors were composed of clear cells with abundant granular cytoplasm growing as solid sheets with focal acinar, microcystic, and papillocystic areas. Immunohistochemical stains showed strong positivity of the tumor cells for low-molecular-weight cytokeratins and epithelial membrane antigen (EMA). Focal weak cytoplasmic positivity was observed in three cases with alpha-1-antichymotrypsin and in one case with amylase. Stains for vimentin, S-100 protein, chromogranin, and lysozyme were negative in all cases examined. Electron microscopy performed in four cases showed abundant zymogen-type cytoplasmic granules of variable electron density characteristic of acinar-type secretory cells. All patients were treated by lobectomy alone. Follow-up of 3 to 10 years in four cases revealed that all patients were alive and well, with no evidence of recurrence or metastases. Because of their relatively indolent behavior and favorable prognosis, primary acinic cell carcinoma of the lung must be distinguished from other primary and metastatic clear cell tumors of the lung.

Antigen binding properties of highly purified bispecific antibodies

A panel of three bispecific monoclonal antibodies (bsMAbs) binding to follitropin (FSH) and to beta-galactosidase have been prepared by fusion of hybridoma cell lines resistant to oubain and neomycin. One of these bispecific antibodies contains heavy chains of the same IgG subclass, and two are composed of heavy chains of different IgG subclasses. We have investigated methods for the purification of bispecific antibodies from hybrid hybridoma supernatant fluids grown in serum-free medium. Following ammonium sulfate precipitation, bispecific antibodies can be purified in a single step by mixed mode ion-exchange HPLC on Bakerbond Abx columns. In one case, three species were resolved by ion-exchange HPLC and functional analysis showed that two peaks contained parental antibodies, and the third contained the bispecific. Ion-exchange HPLC purification of serum-free preparations from two other hybrid hybridomas resolved seven protein-containing peaks, only one of which was active in a bispecific ELISA. The equilibrium affinity constants for each of the parental antibodies for both FSH and beta-galactosidase were determined and found to be similar to those of the purified bsMAbs. Further, the association of FSH to one binding site on a bispecific antibody was shown to have no effect on the equilibrium binding constant for beta-galactosidase binding to the other site. Our results suggest that bsMAbs can be readily purified from hybrid hybridomas by a simple and rapid method, and the binding of antigen to one binding site on a bsMAb is independent of antigen binding to the second site.

From the archives of the AFIP. Mediastinal germ cell tumors: radiologic and pathologic correlation

Germ cell tumors occur most frequently in the gonad but can rarely occur in extragonadal locations, usually in or near the midline. The most common extragonadal site of primary germ cell tumors is the anterior mediastinum. The most common histologic type of mediastinal germ cell tumor is mature teratoma, which is typically asymptomatic and incidentally discovered. Radiographically, these tumors appear as rounded, often lobulated masses; calcification may be seen. Imaging studies of mature teratoma frequently demonstrate cystic components and may demonstrate fat or calcium. Malignant germ cell tumors usually occur as large masses in symptomatic young male patients. Seminomas are typically of homogeneous soft-tissue attenuation, and nonseminomatous malignant germ cell tumors are typically of heterogeneous attenuation on computed tomographic scans. Therapy varies according to cell type and may include surgery, radiation therapy, or chemotherapy. Prognosis is excellent for patients with mature teratoma, good for patients with pure seminoma, and poor for patients with nonseminomatous malignant germ cell tumors and mixed germ cell tumors.

The spectrum of histologic growth patterns in benign and malignant fibrous tumors of the pleura

A review of the histologic growth patterns in 50 cases of benign and malignant fibrous tumors of the pleura (localized or solitary fibrous tumor, fibrous mesothelioma) is presented. Two major histologic growth patterns were observed admixed in various proportions: solid spindle and diffuse sclerosing. The solid spindle growth pattern assumed various configurations, including fascicular areas, storiform and herringbone formations, angiofibroma and hemangiopericytoma-like areas, synovial sarcoma-like areas, and neural-type palisading, thus simulating a variety of soft-tissue neoplasms. The diffuse sclerosing pattern, although rarely assuming a dominant role, was present in varying proportions in virtually all cases. In areas with extensive sclerosis, focal degeneration of collagen simulating tumor necrosis was often present. Other less frequently observed features were the formation of "amianthoid" fibers, multinucleated giant cells, and foci of metaplastic ossification. On ultrastructural and immunohistochemical examination, the tumor cells showed nondistinct features. Due to the extreme variability in morphologic appearances and the lack of distinctive ultrastructural or immunohistochemical characteristics, these tumors can pose a significant diagnostic problem. Familiarity with their histologic appearances and correlation with the gross findings and clinical setting are essential for arriving at the correct diagnosis.

Thymomas presenting as pleural tumors. Report of eight cases

Eight cases of thymomas presenting as pleural-based lesions are presented. The patients are five men and three women between the ages of 38 and 71 years (mean 54.5). Histologically, six tumors showed morphologic features indistinguishable from classical mediastinal thymomas, namely lobulation produced by fibrous bands and a biphasic cell population composed of epithelial cells admixed with small lymphocytes. One case showed prominent spindle cell configuration and marked vascularization resulting in a hemangiopericytomalike appearance; in another case, the epithelial component was associated with cystic structures. The radiographic findings were diffuse pleural thickening with encasement of the lung in four cases; an ill defined mass involving the right diaphragmatic pleura with engulfment of the left lower lobe in one case; diffuse pleural thickening along the mid lateral axillary line in one case; and left-sided pleural masses involving the diaphragmatic and chest wall pleural surfaces in another. In the remaining case, a massive unilateral left pleural effusion obscured the underlying lesion. Clinically, the patients presented with varied symptoms, including shortness of breath, fever, and weight loss. Follow-up information was obtained in four patients. One patient died 1 month after initial diagnosis, but no details of the cause of death were available. Another had metastasis to the groin 1 year after diagnosis. The other two patients were alive and well 2-10 years after the initial diagnosis.

Epstein-Barr virus in Hodgkin's disease from patients with human immunodeficiency virus infection

The polymerase chain reaction (PCR) technique was used to detect the presence of Epstein-Barr virus (EBV) DNA sequences in Hodgkin's disease specimens from 10 patients who were also positive for the human immunodeficiency virus (HIV). Eight of 10 specimens were positive for EBV, compared to 23 of 57 Hodgkin's disease specimens from patients without HIV infection, suggesting a closer association between Epstein-Barr virus infection and Hodgkin's disease in patients with HIV infection than in the general population.

Thymoma: radiologic-pathologic correlation

Thymoma is the most common primary neoplasm of the thymus. The majority of thymomas are encapsulated masses and exhibit a benign behavior. Less frequently, thymomas may be locally invasive, or rarely they may metastasize to distant sites. The usual clinical presentation is that of an anterior mediastinal mass found incidentally in an asymptomatic patient. The variable gross features of thymoma and the potential for local invasion result in a variety of radiologic appearances. The most common radiologic manifestation is a rounded, soft-tissue mass of the anterior superior mediastinum. Computed tomography and magnetic resonance imaging typically show a prevascular mediastinal mass of variable size and may be helpful in the evaluation of adjacent structures in cases of invasive thymoma. The treatment of choice is complete surgical excision. Radiation therapy and chemotherapy may be used adjunctively to surgery in the treatment of invasive tumors. The prognosis of encapsulated thymoma is generally favorable. Invasive tumors are associated with a worse prognosis but may respond to radical resection.

Primary adenocarcinoma of the nasal cavity and paranasal sinuses

Eight cases of primary adenocarcinoma of the nasal cavity associated with wood dust exposure are reported. The patients include seven men and one woman between the ages of 31 and 81 years. All the patients had a history of wood dust exposure. Carpentry was the occupation in four patients; inspector for railroad boxcars in one; teacher in a wood-work shop in another and worker in a desk factory in the other. The only female patient was a school teacher whose husband had a wood-work shop at home. Clinically, epistaxis and/or nasal obstruction were the most common symptoms. The histology of the tumors varied and consisted of well differentiated adenocarcinoma, clear cell adenocarcinoma, papillary-mucinous adenocarcinoma, and "colonic-type" adenocarcinoma. Follow-up data showed that three patients were alive of whom two had either recurrent or metastatic disease at one and three years following the initial diagnosis, respectively. The third patient was alive and well four years after initial diagnosis. Three other patients died but a direct cause of death was not identified. The remaining two patients were lost to follow-up.

Variant serotypes of infectious bronchitis virus isolated from commercial layer and broiler chickens

Twenty infectious bronchitis virus (IBV) field isolates obtained from commercial layer and broiler chickens in 1987 and 1988 were serotyped using the virus-neutralization (VN) test. Six different previously unrecognized variant serotypes were identified from a total of seven isolates from layer chickens. Only two isolates, both from Maine, were the same variant serotype. Variant serotypes also were recovered from layer flocks in Illinois and Washington and the province of Ontario, Canada. Two different variants were isolated from the same multi-age layer complex in Connecticut. Only one of 13 broiler chicken isolates was found to be a new variant serotype, that being from birds reared in Delaware. Cross-protection studies in specific-pathogen-free chickens indicated that vaccines containing the Holland, L-1, or Connaught strains of Massachusetts (Mass) combined with Arkansas produced a broader spectrum of immunity against challenge with the layer variants than Mass (Holland) alone or Mass (L-1) + Connecticut. All vaccines tested produced solid immunity (greater than or equal to 80% protection) against the broiler variant virus.

Identification of titanium in human tissues: probable role in pathologic processes

Six cases of titanium dioxide exposure involving lung, skin, and synovium are described, with a review of the literature. The patients, four men and two women, were between the ages of 22 and 65 years. The pulmonary changes were characterized by fibrosis and numerous macrophages with abundant deposition of a black pigment. Adjacent areas of bronchopneumonia were also observed. In the skin a severe necrotizing lesion involving the subcutaneous tissue with extension to the muscle was observed in one case and a nonspecific inflammatory response was observed in another; both cases showed abundant black pigment deposition. Electron microscopy and energy dispersive x-ray analysis demonstrated the presence of large quantities of titanium in the pigment granules. There may be a combination of black pigment deposition and fibrosis, necrosis, or a xanthomatous or granulomatous reaction, that, together with negative results on special staining and culture studies for organisms, should raise the suspicion of titanium-associated injury and prompt the study of the affected tissues by x-ray analysis for positive identification.

Syringomatous squamous tumors of the breast

Four cases are reported of syringomatous squamous tumors of the breast occurring in women aged 37 to 70 years. The lesions were characterized histologically by relatively well-circumscribed tumor-like nodules composed of a proliferation of teardrop or comma-shaped islands of squamous epithelium. The squamous epithelial islands contained central lumens lined by eosinophilic cuticles and were surrounded by a densely cellular fibrous matrix, thus closely resembling the growth pattern of dermal eccrine syringomas. The lesions appeared to arise de novo from breast parenchyma without evidence of transitions with the surrounding normal or hyperplastic mammary epithelium and were not associated with the overlying skin or nipple epidermis. In all cases, the surrounding breast tissue showed fibrocystic and benign proliferative changes, and in one case, the lesion was found in the vicinity of a large cyst surrounded by microcalcifications. All patients were treated by local surgical excision and have shown no evidence of recurrence over a follow-up period of 1 to 6 years. The histologic differential diagnosis and the possible pathogenesis of these lesions are discussed.

Nodular regenerative hyperplasia of the liver in children

Sixteen cases of nodular regenerative hyperplasia of the liver in children are presented. The patients, 10 girls and 6 boys, were between the ages of 7 months and 13 years, with a median of 6 years. Clinically, nine children presented with hepatomegaly or splenomegaly, with and without signs of portal hypertension. A history of anticonvulsant drug therapy was obtained in four patients. Associated conditions in the remaining three cases were Donohue's syndrome, disseminated intravascular coagulation, and angiomyolipoma of the kidney. In five patients a clinical diagnosis of primary intra-abdominal tumor was made. Follow-up showed that six patients died of causes unrelated to the nodular hyperplasia. Two patients were asymptomatic when last seen 5 and 18 years after the initial diagnosis of nodular hyperplasia. Both patients underwent shunt surgery. No follow-up was available for eight patients. The importance of recognizing this entity in the pediatric age group, as well as its histopathologic differential diagnosis, is stressed.

Benign mixed tumors (pleomorphic adenomas) of the breast

Six cases of benign mixed tumors of the female breast are described. The tumors were found in three settings: (a) as a de-novo lesion arising from breast parenchyma, (b) as single or multiple nodules arising in a background of benign proliferative epithelial elements, and (c) in association with breast carcinoma. The tumors ranged from 1 to 4 cm in diameter, and were histologically characterized by the admixture in various proportions of benign glandular epithelial and myoepithelial elements and cartilaginous or myxoid components. Immunohistochemical staining supported this interpretation. One of the cases was remarkable for the presence of abundant tyrosine-like crystals, a feature described in benign mixed tumors of salivary glands. None of the tumors has recurred during a follow-up period of 1-7 years. Mixed tumors of the breast are considered to be similar to their dermal and salivary gland counterparts.

Morphometric analysis of germinal centers in nonthymomatous patients with myasthenia gravis

A morphometric analysis of germinal centers (GCs) in the thymus of nonthymomatous patients with myasthenia gravis was performed in 26 patients, including 14 women and 12 men. The GCs were evaluated for number, diameter, perimeter, and cross-sectional area using a computerized interactive morphometric analysis. The GCs ranged from 2 to 19 per case, with an average diameter of 0.02 to 0.43 mm, a perimeter of 0.38 to 1.35 mm, and a cross-sectional area of 0.01 to 0.14 mm2. In thymic sections with fewer than five GCs, the GCs had a mean area of 0.05 mm2, a perimeter of 0.84 mm, and a diameter of 0.24 mm. In thymic sections containing five or more GCs, the GCs had a mean area of 0.04 mm2, a perimeter of 0.62 mm, and a diameter of 0.19 mm. The clinical improvement in these patients inversely correlated with the above parameters, with improvement being observed in patients whose GCs had a mean area of 0.02 mm2, a perimeter of 0.58 mm, and a diameter of 0.17 mm. No correlation was observed between the number of GCs and clinical improvement. The results of our study appear to indicate that computerized interactive morphometric analysis may represent a potentially useful method for the evaluation of the morphometric features of thymic GCs and their correlation with clinical outcome in patients with myasthenia gravis.

Deciduosis of the appendix

A clinicopathologic and immunohistochemical study of six cases of deciduosis of the appendix is presented. The patients were pregnant women aged 18-40 years. In four cases, the patients presented with signs and symptoms of acute appendicitis during their 26th to 31st week of pregnancy; in the other two, the lesions were discovered incidentally in appendectomy specimens obtained during cesarean section and tubal ligation at term. Histologically, the lesions were characterized by the presence of multiple, irregularly distributed submesothelial deposits of decidualized cells in the serosa of the appendix, without any associated evidence of endometriosis. By immunohistochemistry, the decidualized cells strongly labelled with vimentin antibodies, consistent with their stromal origin. In two cases, coexpression of vimentin and desmin intermediate filaments was observed, suggestive of myoid differentiation. The possible relationship of the lesions with the development of symptoms of peritoneal irritation in these patients is discussed along with a review of the literature on the abdominal complications of ectopic decidua.

Malignant fibrous histiocytoma of the glans penis

A case of malignant fibrous histiocytoma of the penis in a 56-year-old Hispanic man is described. The tumor was composed of a proliferation of atypical spindle cells showing the characteristic storiform growth pattern. Immunohistochemical stains were positive for vimentin and alpha-1-antichymotrypsin and negative for keratin, desmin, and S-100 protein antibodies. The unusual location of this tumor in our patient highlights the ubiquitous distribution of this malignant neoplasm. The clinical and histologic differential diagnosis of this lesion is discussed.

Anatomy of the hand

The anatomy of the hand is efficiently organized to carry out a variety of complex tasks. These tasks require a combination of intricate movements and finely controlled force production. The shape of the bony anatomy in conjunction with the arrangement of soft tissues contributes to the complex kinesiology of the hand. Injury to any of these structures can alter the overall function of the hand and therefore complicate the therapeutic management. The purpose of this article is to review the anatomy of the hand with special emphasis on structures that relate to management of hand injuries.