Mixed diquat/paraquat-induced burns

BACKGROUND

Ducatalon is a bipyridylium herbicide containing a mixture of diquat and paraquat, and is used in agriculture. Adverse reactions due to contact of this compound with the skin have rarely been described.

CASE REPORTS

Two men were seen for severe pain due to extensive chemical burns in the perineal and scrotal regions, caused by leaking of Ducatalon from defective equipment used for spraying the herbicide. The lesions responded well to treatment with topical silver sulfadiazine, combined with systemic antibiotics. The damaged skin healed without scarring within a few days. The lesions have not recurred after the faulty spraying apparatus was replaced.

CONCLUSION

Direct contact of the skin with Ducatalon may lead to severe chemical burns. Proper precautions should be taken by the personnel handling this compound, with particular attention to the integrity of the equipment used for spraying the herbicide.

Hyalinizing spindle and epithelioid cell nevus. A study of five cases of a distinctive histologic variant of Spitz's nevus

Five cases are described of a distinctive histologic variant of benign spindle and epithelioid cell nevus characterized by extensive and prominent stromal hyalinization. The lesions consisted of a proliferation of spindle or epithelioid nevocytes scattered singly or in small clusters in the dermis and surrounded by abundant paucicellular hyalinized or collagenous stroma. Three patients were men and two were women. Their age range was 23 to 45 years (mean, 32). Two of the lesions were located in the head and neck region, two in the lower extremities, and one in the trunk. Immunohistochemical strains showed positive staining of the spindle or epithelioid cells with S-100 protein and vimentin; stains for keratin, EMA, CEA, actin, and desmin were all negative. Van Gieson and trichrome histochemical reaction demonstrated the collagenous nature of the hyalinized intercellular matrix; Congo red, crystal violet, and alcian blue stains were all negative. The etiology and pathogenesis of the intercellular hyalin deposits are unknown, but they probably represent a regressive phenomenon in longstanding or involuting lesions. Hyalinizing Spitz nevus must be included in the differential diagnosis of cutaneous lesions exhibiting a prominent hyalinized stroma and must be differentiated from other dermal neoplasms, particularly cutaneous metastases from occult internal malignancies and malignant melanoma.

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.

Tricholemmal carcinoma. A clinicopathologic study of 13 cases

We describe 13 cases of tricholemmal carcinoma, a rarely recognized cutaneous adnexal neoplasm. The patients were nine men and four women. In general, the tumors presented as slow-growing epidermal papules, indurated plaques, or nodules showing predilection for sun-exposed, hair-bearing skin. The lesions were most frequently misdiagnosed clinically as basal cell carcinoma. Histologically, they showed a variegation of growth patterns including solid, lobular, and trabecular; they were characterized by a proliferation of epithelial cells with features of outer root sheath differentiation, including abundant glycogen-rich, clear cytoplasm, foci of pilar-type keratinization, and peripheral palisading of cells with subnuclear vacuolization. Because of their variable growth pattern, overt cytologic atypia, abundant clear cytoplasm, occasional pagetoid intraepidermal spread, and brisk mitotic activity, these tumors may pose difficulties for diagnosis and be confused with other malignant skin tumors with clear cell changes. Despite the seemingly malignant cytological appearance of these lesions, clinical follow-up in 10 cases showed no recurrence or metastasis over a period of 2-8 years. Thus, conservative surgical excision with clear margins appears to be the treatment of choice for these neoplasms.

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.

On the discriminatory value of anti-HPCA-1 (CD-34) in the differential diagnosis of benign and malignant cutaneous vascular proliferations

The staining pattern of monoclonal antibody anti-HPCA-1 (CD-34) was studied in 95 cases of benign and malignant cutaneous vascular proliferations and compared with other vascular endothelium-associated antigenic markers in paraffin-embedded tissues. The proliferating vessels in 22 cutaneous capillary hemangiomas, 8 lobular capillary hemangiomas, and 1 case of papillary intravascular endothelial hyperplasia stained strongly positively for anti-HPCA-1, and the intensity of the reaction was paralleled by that of factor VIII-related antigen (FVIII), Ulex europaeus lectin-1 (UEA), and vimentin (VIM). The vessels in 10 cases of granulation tissue, 6 cases of cavernous hemangioma, 6 cases of angiokeratoma, 5 cases of angiolymphoid hyperplasia with eosinophilia (epithelioid hemangioma), and 3 cases of bacillary angiomatosis showed a lack of reactivity with anti-HPCA-1 and staining of variable intensity with the other markers. Twenty cases of Kaposi's sarcoma (seven patch, five plaque, eight nodular stage) showed strong labeling with anti-HPCA-1 in small, well-formed vessels scattered among the spindle-cell proliferation, and four of these cases showed focal positivity of scattered spindle cells. Nine cases of cutaneous angiosarcoma, two cases of low-grade epithelioid angiosarcoma, and one case of spindle-cell hemangioendothelioma were negative for anti-HPCA-1 and showed variable reactivity for FVIII and UEA; all cases stained strongly positively for VIM. The results of this study indicate that although anti-HPCA-1 shows a high sensitivity for the staining of normal vascular endothelium, its specificity may be restricted to mature, well-formed vessels, therefore rendering its discriminatory value very limited for the identification of poorly differentiated vascular endothelial neoplasms.

Polymorphous sweat gland carcinoma

We describe nine cases of a distinctive cutaneous neoplasm showing features of eccrine adnexal differentiation that were characterized by their variegated histological appearance and low-grade malignant behaviour. The term polymorphous sweat gland carcinoma is proposed to designate these lesions. The tumours presented as large, long-standing, slow growing, dermal nodules showing a marked predilection for the extremities. Six patients were women. The patients were aged 42-70 years (mean, 59.8 years). Histologically, the lesions were characterized by a highly cellular proliferation displaying a variety of growth patterns, including solid, trabecular, tubular, pseudopapillary and cylindromatous, with prominent stromal changes including haemorrhage, hyalinization and cystic change, and displaying moderate cytological atypia and mitoses. Focal areas showing features associated with eccrine differentiation (i.e. tubular structures, small glandular lumina) could be identified in all cases. Clinical follow-up in six cases showed that two of the lesions recurred locally over a period of 3-6 years, and one tumour metastasized to regional lymph nodes 3 years after excision. Polymorphous sweat gland carcinoma should be considered in the differential diagnosis of neoplastic epithelial dermal proliferations; complete but conservative surgical excision appears to be the treatment of choice for these lesions.

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.

Clear cell eccrine carcinomas of the skin. A clinicopathologic study of nine patients

BACKGROUND

Sweat gland carcinomas with clear cell features are extremely rare neoplasms, with few well documented cases reported in the literature.

METHODS

Data on nine patients with malignant eccrine adnexal neoplasms characterized by a prominent clear cell neoplastic component were studied. Immunohistochemical stains with a panel of antibodies against epithelial, stromal, and neural antigens were performed on five tumors and electron microscopic examination of one.

RESULTS

The tumors showed a spectrum of histologic features and growth patterns that ranged from well differentiated, low grade malignant neoplasms to poorly differentiated, highly aggressive, recurrent, and metastasizing tumors. All tumors contained a varied proportion of cells with abundant clear cytoplasm, similar to those seen in a group of benign eccrine adnexal neoplasms that have been variously designated as clear cell hidradenoma, nodular hidradenoma, clear cell myoepithelioma, and eccrine acrospiroma. Immunohistochemical stains on five tumors and ultrastructural examination in one were consistent with eccrine differentiation. Clinical follow-up of eight patients showed local recurrence in six, followed by metastases in three, despite local excision, radiation, and chemotherapy. Criteria for differentiating these tumors from their benign counterparts and from other types of malignant adnexal neoplasms and metastatic lesions are presented.

CONCLUSIONS

The findings indicate that clear cell eccrine carcinomas comprise a heterogeneous group of lesions that may range from locally recurring, low grade well differentiated tumors to highly aggressive, high grade tumors with a definite potential for uncontrollable local recurrence and metastasis. Wide surgical excision is recommended as the primary treatment for such neoplasms.

Epithelioid leiomyosarcoma of the skin and subcutaneous tissue. Clinicopathologic, immunohistochemical, and ultrastructural study of five cases

This report describes five cases of an unusual variant of malignant smooth-muscle neoplasm involving the skin and subcutaneous tissue characterized by a proliferation of predominantly round to oval epithelioid cells with abundant eosinophilic cytoplasm. Of the five patients, four were men, one a woman; ages ranged from 69 to 85 years (mean, 76.4). The size of the lesions varied from 1.2 to 2.5 cm; two were located in the scalp, two in the face, and one in the back of the neck. Immunohistochemical evaluation of the tumor cells showed immunoreactivity for actin and vimentin in all cases and negative labeling for desmin, S-100 protein, keratin, epithelial membrane antigen, HMB-45, factor VIII, and alpha-1-antichymotrypsin. Ultrastructural examination showed features of smooth muscle differentiation, that is, focal plasmalemmal densities, basement membrane material, and cytoplasmic filaments with focal condensations. All patients were treated by surgical excision and two also with post-operative radiotherapy. Two cases recurred after 1 year, requiring wide excision. A second recurrence from one of these cases showed the emergence of a highly anaplastic, pleomorphic spindle cell sarcoma; the patient died of unrelated causes, with evidence of persistent disease, after 2 years. In the remainder of cases, the patients were alive and well with no evidence of recurrence or metastasis from 2 to 6 years. Because of the unusual morphologic features of this variant of smooth-muscle tumor it may be confused with a variety of primary and metastatic neoplasms of the skin, including malignant melanoma, epithelioid sarcoma, and metastatic carcinoma. Epithelioid leiomyosarcoma should be recognized as a distinct morphologic variant of primary cutaneous smooth muscle neoplasm and should be considered in the differential diagnosis of epithelioid neoplasms in dermal and superficial soft tissue locations.

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.

Mucinous meningioma. Report of an unusual variant of meningioma that may mimic metastatic mucin-producing carcinoma

An unusual variant of meningioma is described that was characterized by small clusters and strands of meningothelial cells surrounded by abundant mucinous stroma. The unusual appearance of the lesion prompted an initial diagnosis of metastatic mucin-secreting carcinoma (so-called colloid carcinoma) resulting in extensive clinical evaluation in search for a primary. Histochemical studies showed the mucinous material to be composed of strongly sulfated acid mucopolysaccharides rich in hyaluronic acid. Immunohistochemical studies showed strong membrane staining of the tumor cells with epithelial membrane antigen and positive cytoplasmic staining with vimentin antibodies. Ultrastructural examination revealed the characteristic features of meningothelial cells (i.e., abundant long, interdigitating cytoplasmic processes joined by well-developed cell junctions) but failed to demonstrate secretory activity within the neoplastic cells. The prominent mucinous stroma in this case most probably represents a nonspecific reaction of stromal cells to an undetermined stimulus. Mucinous meningioma should be added to the list of morphologic variants of meningioma and should be considered in the differential diagnosis of mucinous lesions in intracranial locations.

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.

Treatment of epidermal cysts with Solcoderm (a copper ion and acid solution)

The treatment of epidermal cysts has often posed a problem for dermatologists. Although surgical excision has been adopted as the method of choice for the removal of these lesions, complications of surgery and recurrences have warranted the search for alternate therapeutic modalities. Use of a recently introduced compound, Solcoderm, is reported in the treatment of 116 epidermal cysts in 85 patients over a 2-year period. The satisfactory cosmetic results observed, low incidence of recurrence, low cost and ease of administration, make this drug a viable alternative in the management of epidermal cysts, particularly in those cases where surgery should be avoided.

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.

Squamous differentiation in malignant eccrine poroma

Squamous differentiation in poral adnexal neoplasms is a rare event. Two cases are presented of malignant eccrine poroma in which areas of squamous differentiation showing the features of squamous cell carcinoma were present. The areas of squamous differentiation were found within the invasive components of the lesions and appeared to result from direct transformation of the poral epithelial cells. A review of the literature on this unusual phenomenon is presented.

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.

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.

Benign trichogenic tumours: a report of two cases supporting a simplified nomenclature

We report two cases of a rare benign tumour of hair germ. Clinically, both were solitary, well-circumscribed, subcutaneous nodules located in the extremities. Histologically, the tumours were characterized by nests and thin cords of basaloid epithelial cells intimately associated with a cellular stroma. The basaloid cells exhibited peripheral palisading, keratinization in the form of keratotic cysts and squamoid transformation, and pilar differentiation. An unusual, but distinctive, cribriform pattern of growth was observed. There was no communication with the overlying epidermis. Abundant primitive hair germinal buds and rare more advanced abortive hair follicles were identified. These histological appearances encompass features of both trichoblastic fibroma and trichogenic trichoblastoma, thus distinguishing these neoplasms from other skin tumours and reinforcing the hypothesis that these tumours are closely related from a histogenetic point of view. The presence of overlapping histological features can be problematic for practising histopathologists who rarely encounter these conditions. With this in mind, the term benign trichogenic tumour may be more appropriate to encompass these two tumours and related neoplasms that appear to lie within the spectrum of hair follicle development.