Smoking-related idiopathic interstitial pneumonia

Cigarette smoking is a key factor in the development of numerous pulmonary diseases. An international group of clinicians, radiologists and pathologists evaluated patients with previously identified idiopathic interstitial pneumonia (IIP) to determine unique features of cigarette smoking. Phase 1 (derivation group) identified smoking-related features in patients with a history of smoking (n=41). Phase 2 (validation group) determined if these features correctly predicted the smoking status of IIP patients (n=100) to participants blinded to smoking history. Finally, the investigators sought to determine if a new smoking-related interstitial lung disease phenotype could be defined. Phase 1 suggested that preserved forced vital capacity with disproportionately reduced diffusing capacity of the lung for carbon monoxide, and various radiographic and histopathological findings were smoking-related features. In phase 2, the kappa coefficient among clinicians was 0.16 (95% CI 0.11-0.21), among the pathologists 0.36 (95% CI 0.32-0.40) and among the radiologists 0.43 (95% CI 0.35-0.52) for smoking-related features. Eight of the 100 cases were felt to represent a potential smoking-related interstitial lung disease. Smoking-related features of interstitial lung disease were identified in a minority of smokers and were not specific for smoking. This study is limited by its retrospective design, the potential for recall bias in smoking history and lack of information on second-hand smoke exposure. Further research is needed to understand the relationship between smoking and interstitial lung disease.

From the radiologic pathology archives: organization and fibrosis as a response to lung injury in diffuse alveolar damage, organizing pneumonia, and acute fibrinous and organizing pneumonia

Organization, characterized by fibroblast proliferation, is a common and nearly universal response to lung injury whether it is focal or diffuse. Despite the vast range of injurious agents, the lung's response to injury is quite limited, with a similar pattern of reaction seen radiologically and histologically regardless of the underlying cause. Although there is a tendency to divide organization into distinct entities, the underlying injury to the alveolar epithelial basement membrane is a uniting factor in these processes. This pattern of lung injury is seen in the organizing phase of diffuse alveolar damage, organizing pneumonia (OP), acute fibrinous and organizing pneumonia, and certain types of fibrotic lung disease. In addition, although organization can heal without significant injury, in some instances it progresses to fibrosis, which can be severe. When fibrosis due to organization is present, other histologic and imaging patterns, such as those seen in nonspecific interstitial pneumonia, can develop, reflecting that fibrosis can be a sequela of organization. This article reviews the histologic and radiologic findings of organization in lung injury due to diffuse alveolar damage, OP, and acute fibrinous and organizing pneumonia and helps radiologists understand that the histologic and radiologic findings depend on the degree of injury and the subsequent healing response.

Tumor genetics and survival of thymic neuroendocrine neoplasms: a multi-institutional clinicopathologic study

Thymic neuroendocrine tumors (TNET) are rare primary epithelial neoplasms of the thymus. This study aimed to determine clinically relevant parameters for their classification and for therapeutic decisions. We performed a comprehensive histological, clinical, and genetic study of 73 TNET cases (13 thymic typical carcinoids [TTC], 40 thymic atypical carcinoids [TAC], and 20 high-grade neuroendocrine carcinomas [HGNEC] of the thymus), contributed by multiple institutions. The mean number of chromosomal imbalances per tumor was 0.8 in TTC (31% aberrant cases) versus 1.1 in TAC (44% aberrant cases) versus 4.7 in HGNEC (75% aberrant cases). Gains of 8q24 (MYC gene locus) were the most frequent alteration and one of the overlapping features between carcinoids and HGNEC. The 5-year survival rates for TTC, TAC, and HGNEC were 100, 60, and 30%. The 10-year survival rates for TTC and TAC were 50 and 30% (P = 0.002). Predictive mitotic cut-off values for TTC versus TAC were 2.5 per 10 high-power fields (HPF; indicating a higher death rate, P = 0.062) and 15 per 10 HPF (indicating higher risk of recurrence, P = 0.036) for separating HGNEC from TAC. We conclude that the current histopathologic classifications of TNET reflect tumor biology and provide important information for therapeutic management.

From the radiologic pathology archives: cardiac lymphoma: radiologic-pathologic correlation

Lymphoma of the heart and pericardium is usually present as one aspect of disseminated disease and rarely occurs as a primary malignancy. It accounts for 1.3% of primary cardiac tumors and 0.5% of extranodal lymphomas. Cardiac lymphomas are most commonly diffuse large cell lymphomas and frequently manifest as an ill-defined, infiltrative mass. Atrial location is typical; the right atrium is most often affected. Pericardial thickening or effusion is often a common early feature of disease. Infiltration of atrial or ventricular walls with extension along epicardial surfaces is also a notable feature. At computed tomography, the attenuation of cardiac lymphoma may be similar to or lower than that of normal myocardium. At magnetic resonance imaging, it has variable signal intensity and contrast enhancement. Clinical manifestations may include pericardial effusion, cardiac arrhythmias, and a variety of nonspecific electrocardiographic abnormalities, notably first- to third-degree atrioventricular block. Treatment most commonly includes anthracycline-based chemotherapy and anti-CD20 treatment. Chemotherapy has been used alone or combined with radiation therapy. Palliative surgery has been performed, mainly for tumor debulking. The prognosis for patients with either primary or secondary lymphomatous heart involvement is usually poor; late diagnosis is one of the major factors affecting outcome.

Centrilobular emphysema combined with pulmonary fibrosis results in improved survival

Background

We hypothesized that, in patients with pulmonary fibrosis combined with emphysema, clinical characteristics and outcomes may differ from patients with pulmonary fibrosis without emphysema. We identified 102 patients who met established criteria for pulmonary fibrosis. The amount of emphysema (numerical score) and type of emphysema (centrilobular, paraseptal, or mixed) were characterized in each patient. Clinical characteristics, pulmonary function tests and patient survival were analysed.

Results

Based on the numerical emphysema score, patients were classified into those having no emphysema (n = 48), trivial emphysema (n = 26) or advanced emphysema (n = 28). Patients with advanced emphysema had a significantly higher amount of smoking in pack/years than patients with no emphysema or trivial emphysema (P < 0.0001). Median survival [1st, 3rd quartiles] of patients with advanced emphysema was 63 [36, 82] months compared to 29 [18, 49] months in patients without emphysema and 32 [19, 48] months in patients with trivial emphysema (P < 0.001). Median forced vital capacity (FVC) and total lung capacity (TLC) were higher in the advanced emphysema group compared to patients with no emphysema (P < 0.01 and P < 0.001, respectively), whereas median DL_CO did not differ among groups and was overall low. Within the advanced emphysema group (n = 28), further characterization of the type of emphysema was performed and, within these subgroups of patients, survival was 75 [58, 85] months for patients with centrilobular emphysema, 75 [48, 85] months for patients with mixed centrilobular/paraseptal emphysema, and 24 [22, 35] months for patients with paraseptal emphysema (P < 0.01). Patients with advanced paraseptal emphysema had similar survival times to patients without emphysema.

Conclusions

Patients with pulmonary fibrosis combined with advanced centrilobular or mixed emphysema have an improved survival compared with patients with pulmonary fibrosis without emphysema, with trivial emphysema or with advanced paraseptal emphysema.

Hypersensitivity Pneumonitis: Essential Radiologic and Pathologic Findings

Hypersensitivity pneumonitis is a diffuse, granulomatous interstitial lung disease caused by repeated exposure to a wide spectrum of environmental antigens. Clinical, radiologic, and histologic findings are quite variable and mimic many other diseases; therefore, diagnosis depends on a constellation of findings rather than a single defining feature. High-resolution computed tomography (HRCT) plays a critical role in this setting. The presence of centrilobular nodules, multifocal ground glass opacities, and evidence of air trapping in the expiratory phase of respiration is highly suggestive of hypersensitivity pneumonitis and can direct clinicians to the correct diagnosis. For the pathologist, typical HRCT findings not only corroborate the diagnosis of hypersensitivity pneumonitis when the characteristic triad of airway-centered chronic interstitial inflammation, interstitial poorly formed non-necrotizing granulomas, and organizing pneumonia is present on biopsy, but also improve diagnostic confidence in biopsies lacking components of the diagnostic histologic triad. Importantly, the presence of focal or unilateral imaging findings should prompt a careful search by the pathologist for an infectious etiology, thus avoiding errors in determining the significance of granulomas on biopsy. This article reviews the essential radiologic and pathologic findings in hypersensitivity pneumonitis, discusses the primary considerations in the differential diagnosis, and offers an approach to biopsy evaluation.

Variable prevalence of pulmonary hypertension in patients with advanced interstitial pneumonia

BACKGROUND

Pulmonary hypertension may occur in patients with interstitial pneumonia and is associated with increased mortality. We sought to determine the prevalence of pulmonary hypertension in sub-groups of patients with interstitial pneumonia and to investigate possible associations between pulmonary vascular hemodynamics and pulmonary function.

METHODS

The presence or absence of pulmonary hypertension was assessed in 70 patients with advanced interstitial pneumonia who underwent right heart catheterization. The associations of pulmonary hypertension with clinical characteristics and pulmonary function tests were analyzed.

RESULTS

The prevalence of pulmonary hypertension in patients with idiopathic interstitial pneumonia was 29% vs 64% in patients with connective tissue disease-interstitial pneumonia (p = 0.013). African American patients had a significantly higher prevalence of pulmonary hypertension in the entire study population (81% vs 22%, p < 0.001) and in the idiopathic interstitial pneumonia group (70% vs 19%, p < 0.01). Regression analyses revealed no association between mean pulmonary artery pressure (mPAP) and forced vital capacity or mPAP and diffusion capacity of the lung for carbon monoxide in the entire cohort or in sub-groups of patients.

CONCLUSIONS

African American patients and patients with connective tissue disease-interstitial pneumonia had a high prevalence of pulmonary hypertension. Non-African American patients with advanced idiopathic interstitial pneumonia (including idiopathic pulmonary fibrosis) had a low prevalence of pulmonary hypertension.

Pathology of asbestosis- An update of the diagnostic criteria: Report of the asbestosis committee of the college of american pathologists and pulmonary pathology society

Asbestosis is defined as diffuse pulmonary fibrosis caused by the inhalation of excessive amounts of asbestos fibers. Pathologically, both pulmonary fibrosis of a particular pattern and evidence of excess asbestos in the lungs must be present. Clinically, the disease usually progresses slowly, with a typical latent period of more than 20 years from first exposure to onset of symptoms.

DIFFERENTIAL DIAGNOSIS

IDIOPATHIC PULMONARY FIBROSIS: The pulmonary fibrosis of asbestosis is interstitial and has a basal subpleural distribution, similar to that seen in idiopathic pulmonary fibrosis, which is the principal differential diagnosis. However, there are differences between the 2 diseases apart from the presence or absence of asbestos. First, the interstitial fibrosis of asbestosis is accompanied by very little inflammation, which, although not marked, is better developed in idiopathic pulmonary fibrosis. Second, in keeping with the slow tempo of the disease, the fibroblastic foci that characterize idiopathic pulmonary fibrosis are infrequent in asbestosis. Third, asbestosis is almost always accompanied by mild fibrosis of the visceral pleura, a feature that is rare in idiopathic pulmonary fibrosis.

DIFFERENTIAL DIAGNOSIS

RESPIRATORY BRONCHIOLITIS: Asbestosis is believed to start in the region of the respiratory bronchiole and gradually extends outward to involve more and more of the lung acinus, until the separate foci of fibrosis link, resulting in the characteristically diffuse pattern of the disease. These early stages of the disease are diagnostically problematic because similar centriacinar fibrosis is often seen in cigarette smokers and is characteristic of mixed-dust pneumoconiosis. Fibrosis limited to the walls of the bronchioles does not represent asbestosis.

ROLE OF ASBESTOS BODIES

Histologic evidence of asbestos inhalation is provided by the identification of asbestos bodies either lying freely in the air spaces or embedded in the interstitial fibrosis. Asbestos bodies are distinguished from other ferruginous bodies by their thin, transparent core. Two or more asbestos bodies per square centimeter of a 5- mu m-thick lung section, in combination with interstitial fibrosis of the appropriate pattern, are indicative of asbestosis. Fewer asbestos bodies do not necessarily exclude a diagnosis of asbestosis, but evidence of excess asbestos would then require quantitative studies performed on lung digests.

ROLE OF FIBER ANALYSIS

Quantification of asbestos load may be performed on lung digests or bronchoalveolar lavage material, employing either light microscopy, scanning electron microscopy, or transmission electron microscopy. Whichever technique is employed, the results are only dependable if the laboratory is well practiced in the method chosen, frequently performs such analyses, and the results are compared with those obtained by the same laboratory applying the same technique to a control population.

Pathology of asbestosis- An update of the diagnostic criteria: Report of the asbestosis committee of the college of american pathologists and pulmonary pathology society

Asbestosis is defined as diffuse pulmonary fibrosis caused by the inhalation of excessive amounts of asbestos fibers. Pathologically, both pulmonary fibrosis of a particular pattern and evidence of excess asbestos in the lungs must be present. Clinically, the disease usually progresses slowly, with a typical latent period of more than 20 years from first exposure to onset of symptoms.

DIFFERENTIAL DIAGNOSIS

IDIOPATHIC PULMONARY FIBROSIS: The pulmonary fibrosis of asbestosis is interstitial and has a basal subpleural distribution, similar to that seen in idiopathic pulmonary fibrosis, which is the principal differential diagnosis. However, there are differences between the 2 diseases apart from the presence or absence of asbestos. First, the interstitial fibrosis of asbestosis is accompanied by very little inflammation, which, although not marked, is better developed in idiopathic pulmonary fibrosis. Second, in keeping with the slow tempo of the disease, the fibroblastic foci that characterize idiopathic pulmonary fibrosis are infrequent in asbestosis. Third, asbestosis is almost always accompanied by mild fibrosis of the visceral pleura, a feature that is rare in idiopathic pulmonary fibrosis.

DIFFERENTIAL DIAGNOSIS

RESPIRATORY BRONCHIOLITIS: Asbestosis is believed to start in the region of the respiratory bronchiole and gradually extends outward to involve more and more of the lung acinus, until the separate foci of fibrosis link, resulting in the characteristically diffuse pattern of the disease. These early stages of the disease are diagnostically problematic because similar centriacinar fibrosis is often seen in cigarette smokers and is characteristic of mixed-dust pneumoconiosis. Fibrosis limited to the walls of the bronchioles does not represent asbestosis.

ROLE OF ASBESTOS BODIES

Histologic evidence of asbestos inhalation is provided by the identification of asbestos bodies either lying freely in the air spaces or embedded in the interstitial fibrosis. Asbestos bodies are distinguished from other ferruginous bodies by their thin, transparent core. Two or more asbestos bodies per square centimeter of a 5- mu m-thick lung section, in combination with interstitial fibrosis of the appropriate pattern, are indicative of asbestosis. Fewer asbestos bodies do not necessarily exclude a diagnosis of asbestosis, but evidence of excess asbestos would then require quantitative studies performed on lung digests.

ROLE OF FIBER ANALYSIS

Quantification of asbestos load may be performed on lung digests or bronchoalveolar lavage material, employing either light microscopy, scanning electron microscopy, or transmission electron microscopy. Whichever technique is employed, the results are only dependable if the laboratory is well practiced in the method chosen, frequently performs such analyses, and the results are compared with those obtained by the same laboratory applying the same technique to a control population.

Sarcomatoid carcinoma of the lung: histologic criteria and common lesions in the differential diagnosis

CONTEXT

Sarcomatoid carcinoma of the lung is a subset of poorly differentiated non-small cell lung cancers that are diagnostically challenging because they are uncommon, may reveal little of their parent cell of origin, and overlap morphologically with other anaplastic epithelioid and spindle cell tumors that can be primary in, or metastatic to, the lung and pleura.

OBJECTIVE

To review the current histologic classification and diagnostic criteria that identify the 5 subtypes of sarcomatoid carcinoma of the lung and to discuss the most common tumors in the differential diagnosis.

DESIGN

Published classification systems from the World Health Organization and pertinent peer-reviewed articles indexed in PubMed (National Library of Medicine) form the basis of this review.

CONCLUSIONS

Identification of sarcomatoid carcinoma of the lung requires knowledge of specific histologic criteria that define the 5 subgroups, targeted immunohistochemical studies, and correlation with chest imaging to assess distribution of disease and to avoid misdiagnosis.

Overexpression of phospho-eIF4E is associated with survival through AKT pathway in non-small cell lung cancer

PURPOSE

The eukaryotic translation initiation factor complex 4E (eIF4E) is downstream in the mammalian target of rapamycin (mTOR) pathway. This study explored expression of eIF4E and its relationship with the PTEN/AKT and RAS/MEK/ERK pathways in non-small cell lung carcinoma (NSCLC).

EXPERIMENTAL DESIGN

The status of phosphorylated eIF4E (p-eIF4E), phosphorylated AKT (p-AKT), PTEN, phosphorylated tuberin (p-TSC2), phosphorylated mTOR (p-mTOR), phosphorylated S6 (p-S6), and phosphorylated Erk1/2 (p-Erk1/2) was studied using immunohistochemical analysis applied to a tissue microarray containing 300 NSCLCs. Staining results for each antibody were compared with clinical and pathologic features, and the relationship between staining results was explored.

RESULTS

Overexpression of p-eIF4E, p-AKT, p-TSC2, p-mTOR, p-S6, and p-Erk1/2 in NSCLC was found in 39.9%, 78.8%, 5.1%, 46.7%, 27.1%, and 16.6% of tumors, respectively. The phenotype of p-eIF4E correlated positively with that of p-AKT, p-TSC2, and p-S6 (P < 0.001). Overall survival in NSCLC patients was significantly shorter in cases with overexpression of p-eIF4E and p-AKT alone and in combination (log-rank P < 0.001, each). Cases with underexpression of PTEN were limited (6.4%), and this phenotype did not correlate with any clinical variable. In cluster analysis, the p-AKT/p-mTOR/p-eIF4E/p-S6-positive group had significantly shorter survival compared with the survival of all cases (P < 0.001). Multivariate analysis showed that p-eIF4E overexpression is an independent prognostic factor for NSCLC (P = 0.004).

CONCLUSIONS

This study shows that p-eIF4E expression in addition to p-AKT predicts poor prognosis in NSCLC. Moreover, the correlation between expression of p-eIF4E with p-AKT, as well as p-TSC2 and p-S6, indicates that eIF4E activation through the AKT pathway plays an important role in the progression of NSCLC.

Sclerosing hemangioma of the lung

We present a brief review of sclerosing hemangioma, an uncommon but histologically distinctive neoplasm of the lung. Based on immunohistochemical and molecular findings, sclerosing hemangioma is thought to be derived from incompletely differentiated respiratory epithelium. Sclerosing hemangiomas typically present as asymptomatic, peripheral, solitary, well-circumscribed lesions in women with a mean age at diagnosis in the fifth decade. Rare cases are reported to have regional lymph node metastases; however, metastases do not appear to affect long-term survival. Histologically, sclerosing hemangioma is characterized by a distinct constellation of findings including 2 epithelial cell types, surface cells and round cells, which form 4 architectural patterns, papillary, sclerotic, solid, and hemorrhagic. Sclerosing hemangioma of the lung is generally considered to be a benign lesion, and surgical excision is curative without the need for additional treatment.

Deposition of calcium salts in a case of pulmonary zygomycosis: histopathologic and chemical findings

We report a case of pulmonary zygomycosis associated with unusual deposition of calcium salt crystals. The patient was a 75-year-old female who had onset of cough and shortness of breath. She was treated for community-acquired pneumonia but died despite intensive therapy. Postmortem examination revealed diffuse alveolar damage and multifocal necrotizing pneumonia associated with herpes simplex infection and invasive zygomycosis. Birefringent particles were seen associated with fungal elements in the lung parenchyma, within bronchial cartilage, and in blood vessel walls. By infrared spectroscopy, the birefringent particles in the pulmonary parenchyma and within bronchial cartilage had spectral characteristics of calcium oxalate dihydrate and calcium oxalate monohydrate, respectively. The birefringent crystals within vascular walls were identified as calcium carbonate. This case documents the chemical composition and location of 3 different calcium salt crystals in pulmonary zygomycosis. It also shows that among pulmonary fungal infections, calcium oxalate deposition is not restricted to aspergillosis.

Primary Pulmonary Osteosarcoma: A Report of 4 Cases and a Review of the Literature

Primary pulmonary osteosarcoma is very rare. Most cases are secondary deposits from primaries arising in the appendicular skeleton. Four cases of primary osteogenic sarcoma of the lung are described and the literature reviewed for previously reported cases. These pulmonary tumors occur in patients who are in their fourth to seventh decades, that is, an older age group than their primary bone equivalent. There is a slight male predominance. There appears to be a propensity for the left lung, especially the left upper lobe. The clinical presentation is similar to primary (epithelial) lung cancer. Differentiation from pleomorphic carcinomas and other sarcomas is discussed. We know of no predisposing factor(s) in our cases for the development of this tumor.

Lung tumors with neuroendocrine morphology: essential radiologic and pathologic features

CONTEXT

Tumors with neuroendocrine morphology are a distinct subset of lung neoplasms sharing characteristic histologic, immunohistochemical, ultrastructural, and molecular features.

OBJECTIVE

To review the current histologic classification and the diagnostic criteria for the major categories of neuroendocrine tumors of the lung.

DATA SOURCES

Published classification systems from the World Health Organization and pertinent peer-reviewed articles indexed in PubMed (National Library of Medicine) form the basis of this review.

CONCLUSIONS

Accurate classification of the neuroendocrine tumors of the lung requires knowledge of specific criteria separating the major categories, which is essential for determining prognosis and treatment.

From the archives of the AFIP: pulmonary alveolar proteinosis

Pulmonary alveolar proteinosis (PAP) may develop in a primary (idiopathic) form, chiefly during middle age, or less commonly in the setting of inhalational exposure, hematologic malignancy, or immunodeficiency. Current research supports the theory that PAP is the result of pathophysiologic mechanisms that impair pulmonary surfactant homeostasis and lung immune function. Clinical symptomatology is variable, ranging from mild progressive dyspnea to respiratory failure. There is a strong association with tobacco use. The predominant computed tomographic feature of PAP is a "crazy-paving" pattern (smoothly thickened septal lines on a background of widespread ground-glass opacity), often with lobular or geographic sparing. The radiologic differential diagnosis of crazy-paving includes pulmonary edema, pneumonia, alveolar hemorrhage, diffuse alveolar damage, and lymphangitic carcinomatosis. Definitive diagnosis is made with lung biopsy or bronchoalveolar lavage specimens that reveal intraalveolar deposits of proteinaceous material, dissolved cholesterol, and eosinophilic globules. Symptomatic treatment includes whole-lung lavage, and multiple procedures may be required. New therapies directed toward the identified defect in immune defense have met with moderate clinical success.

Idiopathic nonspecific interstitial pneumonia: report of an American Thoracic Society project

RATIONALE

The 2002 American Thoracic Society/European Respiratory Society classification of idiopathic interstitial pneumonias identified nonspecific interstitial pneumonia (NSIP) as a provisional diagnosis. Concern was expressed that NSIP was a "wastebasket" category, difficult to distinguish from other idiopathic interstitial pneumonias.

OBJECTIVES

The following questions were addressed: (1) Is idiopathic NSIP a distinct entity? 2) If so, what are its clinical, radiologic and pathologic characteristics? (3) What is the role of radiology and pathology in establishing the diagnosis? (4) To make a diagnosis of idiopathic NSIP, what other disorders need to be excluded and how should this be done?

METHODS

Investigators who had previously reported cases of idiopathic NSIP were invited to submit cases for review (n = 305). After initial review, cases with complete clinical, radiologic, and pathologic information (n = 193) were reviewed in a series of workshops.

MEASUREMENTS AND MAIN RESULTS

Sixty-seven cases were identified as NSIP. Mean age was 52 years, 67% were women, 69% were never-smokers, and 46% were from Asian countries. The most common symptoms were dyspnea (96%) and cough (87%); 69% had restriction. By high-resolution computed tomography, the lower lung zones were predominantly involved in 92% of cases; 46% had a peripheral distribution; 47% were diffuse. Most showed a reticular pattern (87%) with traction bronchiectasis (82%) and volume loss (77%). Lung biopsies showed uniform thickening of alveolar walls with a spectrum of cellular to fibrosing patterns. Five-year survival was 82.3%.

CONCLUSIONS

Idiopathic NSIP is a distinct clinical entity that occurs mostly in middle-aged women who are never-smokers. The prognosis of NSIP is very good.

Alveolar airspace and pulmonary artery involvement by extramedullary hematopoiesis: a unique manifestation of myelofibrosis

Pulmonary extramedullary hematopoiesis is a rare manifestation of myelofibrosis. We encountered a unique case of pulmonary extramedullary hematopoiesis occurring in a 59-year-old white man, where in addition to the typical foci of interstitial hematopoietic cells, a surgical lung biopsy showed airspace and arterial wall involvement. Airspace foci were associated with acute and organizing alveolar hemorrhage, while within arteries the hematopoietic elements had a striking predilection for the vascular intima. The hematopoietic foci included erythroid precursors, myeloid precursors, and megakaryocytes, which were immunoreactive with hemoglobin, myeloperoxidase, and CD61, respectively. Whether extramedullary hematopoiesis represents in situ embryonic stem cell differentiation or a compensatory seeding of hematopoietic cells from the bone marrow remains to be elucidated. However, familiarity with these findings in the lung could be helpful in uncovering occult hematological disorders accompanied by extramedullary hematopoiesis. Extramedullary hematopoiesis should also be considered as a cause of pulmonary hemorrhage, especially in the setting of myelofibrosis.

Alpha-methylacyl CoA racemase in pulmonary adenocarcinoma, squamous cell carcinoma, and neuroendocrine tumors: expression and survival analysis

CONTEXT

Alpha-methylacyl CoA racemase (AMACR) is an oxidative enzyme involved in isomeric transformation of fatty acids entering the beta-oxidation pathway. AMACR serves as a useful marker in establishing a diagnosis of prostatic malignancy; however, limited information is available in regard to its presence in pulmonary neoplasms.

OBJECTIVE

To investigate AMACR expression within a spectrum of lung carcinomas and its correlation with patients' survival.

DESIGN

Four hundred seventy-seven pulmonary carcinomas, including 150 squamous cell carcinomas, 150 adenocarcinomas, 46 typical carcinoids, 31 atypical carcinoids, 28 large cell neuroendocrine carcinomas, and 72 small cell carcinomas, were studied immunohistochemically using tissue microarray-based samples.

RESULTS

Overall, pulmonary tumors were positive for AMACR in a significant percentage (47%) of cases. Among tumor types, 22% of squamous cell carcinoma, 56% of adenocarcinoma, 72% of typical carcinoid, 52% of atypical carcinoid, 70% of large cell neuroendocrine carcinoma, and 51% of small cell lung carcinoma were positive for AMACR. Furthermore, the Kaplan-Meier analysis revealed that the patients with AMACR-positive small cell carcinoma had better survival (19% vs 5% after 5 years, P = .04) than patients with AMACR-negative tumors. Such survival advantage was seen for patients with stage I-II (P = .01) but not stage III-IV small cell carcinomas (P = .58).

CONCLUSIONS

These results indicate that, similar to prostate cancer, the overexpression of AMACR frequently occurs in pulmonary carcinomas. Additionally, its positive correlation with outcome of stage I-II small cell lung carcinoma warrants further investigation of the AMACR role in the prognosis of this tumor.

Absence of human herpesvirus-8 in pulmonary inflammatory myofibroblastic tumor: immunohistochemical and molecular analysis of 20 cases

Inflammatory myofibroblastic tumors are uncommon lesions composed of spindled myofibroblasts within a variable background of collagen and inflammatory cells. Although the true nature of these lesions is not fully elucidated, identification of consistent cytogenetic alterations in the anaplastic lymphoma kinase (ALK) gene suggests that they may be neoplastic. A small number of inflammatory myofibroblastic tumors have been reported to harbor human herpesvirus-8 (HHV-8), implicating the virus in its pathogenesis. In this study, 20 cases of pulmonary inflammatory myofibroblastic tumor were analyzed for the presence of HHV-8 with immunohistochemical and molecular methods. In all cases, antibodies to the latent nuclear antigen of the virus were applied. Four open reading frames (ORFs), including ORFs K2, 16, 26, and 72, were targeted utilizing real-time polymerase chain reaction (PCR). The cohort included 9 men and 11 women with a mean age of 37 years (range, 1-81). Microscopically, the tumors were composed of cytologically bland spindle cells with myofibroblastic differentiation. On immunohistochemical studies, 20% of cases (4/20) demonstrated diffuse cytoplasmic positivity with ALK. Immunohistochemical staining for the latent nuclear protein of the virus was negative in all cases (0/20). All tumors (100%, 20/20) tested with real-time PCR were negative for all four ORFs, whereas 100% (10/10) of positive control Kaposi sarcoma cases were positive. Her2 gene expression was present in all (20/20) inflammatory myofibroblastic tumors confirming the presence of amplifiable deoxyribonucleic acid in the tissue lysate. This study documents the absence of HHV-8 in pulmonary inflammatory myofibroblastic tumors, suggesting that further investigation is required to clarify the pathogenesis of this lesion.