Sanjay Mukhopadhyay

Subclassification of Non-small Cell Lung Carcinomas Lacking Morphologic Differentiation on Biopsy Specimens: Utility of an Immunohistochemical Panel Containing TTF-1, Napsin A, p63, and CK5/6

The availability of targeted therapies has created a need for precise subtyping of non-small cell lung carcinomas (NSCLCs). The aim of this study was to assess the utility of immunohistochemical markers in subtyping poorly differentiated NSCLC and to compare the results of immunohistochemical staining on biopsies with the corresponding resections. Thirty-nine cases of NSCLC that could not be further classified on biopsy and had subsequent resection specimens were identified. Classification of the tumor was based on the resection specimen using the World Health Organization criteria. All biopsies and resections were stained with CK7, TTF-1, napsin A (novel aspartic proteinase of the pepsin family), p63, CK5/6, and 34&bgr;E12. The specimens included 20 adenocarcinomas (ACs), 15 squamous cell carcinomas (SCCs), and 4 large-cell carcinomas (LCCs). TTF-1 was positive in biopsies from 16 of 20 ACs, 2 of 4 LCCs, and none of the SCCs. p63 was positive in all 15 SCCs, 2 of 20 ACs (both were also positive for TTF-1 and napsin A), and none of the LCCs. CK5/6 was positive in 11 of 15 SCCs (all p63 positive) but none of the ACs or LCCs. Napsin A stained 11 of 19 ACs (all TTF-1 positive) but none of the other tumors. Staining for CK7 was present in 19 of 19 ACs and 9 of 15 SCCs. 34&bgr;E12 stained both SCCs (15 of 15) and ACs (12 of 20). The combination of TTF-1, napsin A, p63, and CK5/6 allowed an accurate classification of 30 of39 (77%) cases. Of 232 pairs of slides (biopsy and resection) stained with immunohistochemical markers, 12 (5%) showed discrepancies in immunohistochemical staining between biopsies and their corresponding resections. Immunohistochemical staining using a combination of TTF-1, napsin A, p63, and CK5/6 allows subclassification of poorly differentiated NSCLCs on small lung biopsies in most cases. Discrepancies in immunohistochemical staining between biopsies and resections are uncommon.

Pulmonary disease due to aspiration of food and other particulate matter: a clinicopathologic study of 59 cases diagnosed on biopsy or resection specimens.

Aspiration of particulate matter is a well-recognized complication in debilitated patients at autopsy but is not widely recognized in surgical pathology material. We have encountered a surprising number of cases on biopsy or resection specimens, and most were unsuspected clinically and pathologically. This study was undertaken to clarify clinical and pathologic features that facilitate the diagnosis of food/particulate matter aspiration pneumonia. Fifty-nine patients were identified with an average age of 57 (range 26 to 85), and a male/female ratio of 2:1. Common presenting symptoms (information available in 36 cases) included dyspnea (14), fever (9), and cough (6). A history of recurrent pneumonia was present in 9. Radiographic data were available in 34 cases. Bilateral infiltrates or nodules were found in 17 cases, whereas the changes were unilateral in 17. Solitary nodules clinically suspicious for neoplasm were present in 13. Aspiration was suspected clinically in only 4 of the 45 cases in which the clinical impression or differential diagnosis was stated. Predisposing factors for aspiration were identified in 32 patients, including esophageal or gastric causes (19), drug use (10), and neurologic conditions (6). Histologically, bronchiolitis obliterans-organizing pneumonia was present in 52 (88%) cases, usually in combination with multinucleated giant cells, acute bronchopneumonia/bronchiolitis, and/or suppurative granulomas. Foreign material was identified in all cases, including most commonly vegetable or food remnants (54 cases), and less often talc or microcrystalline cellulose (7), crospovidone (4), and kayexalate (2). Particulate matter aspiration pneumonia is a more common cause of lung infiltrates and nodules than generally appreciated. The diagnosis should be suspected when multinucleated giant cells, acute bronchopneumonia/bronchiolitis, and/or suppurative granulomas are found in a background of bronchiolitis obliterans-organizing pneumonia. The presence of foreign material confirms the diagnosis.

Immunohistochemical markers in diagnosis of papillary thyroid carcinoma: utility of HBME1 combined with CK19 immunostaining

Papillary thyroid carcinoma and its variants can be difficult to distinguish from cellular adenomatous nodules. Prior studies have advocated various antibodies to aid in the differential diagnosis, but there is little agreement on their utility. We undertook this study to evaluate immunohistochemical markers in the diagnosis and differential diagnosis of papillary thyroid carcinoma. Ten cases of papillary thyroid carcinoma were initially stained for HBME1, CK19, fibronectin1, Ki-67, Calretinin, p16, SFTPB and CITED1. Additionally, two previously untested antibodies to molecules that have been found to be upregulated in papillary thyroid carcinoma (CST6 and EPS8) were also evaluated. Of these, only HBME1, CK19 and fibronectin1 showed diagnostic utility. These three markers were then further evaluated in 51 papillary thyroid carcinomas and 57 benign thyroids. HBME1 was the most sensitive and specific marker, staining 49/51 papillary thyroid carcinomas and only 4/57 benign thyroids. CK19 was equally sensitive staining all 51 papillary thyroid carcinomas, but it was nonspecific staining 39 of 57 benign thyroids. A negative result, however, was helpful in excluding papillary thyroid carcinoma. Fibronectin1 was positive in 35/51 papillary thyroid carcinomas (69%) and 4/57 (7%) benign thyroids, but its utility was hampered by high background staining. These findings suggest that the combination of HBME1 and CK19 has the greatest diagnostic utility in the differentiation of papillary thyroid carcinoma from its benign mimics.

Pulmonary Meningothelial-like Nodules : New Insights Into a Common but Poorly Understood Entity

Although pulmonary meningothelial-like nodules (MLNs) have been recognized for decades, their nature and significance remain uncertain. This study was undertaken to evaluate MLNs in a wide range of specimens to clarify their incidence, distribution, relation to age and underlying disease, and histogenesis. Five hundred surgical lung biopsies, 25 extensively sampled lobectomies, 20 resections for pneumothoraces in persons younger than 30 years, and 92 pediatric autopsies were examined. Immunohistochemistry was performed in selected cases. One hundred eighty-six MLNs were identified in 81 cases, including 69 of 500 (13.8%) surgical biopsies and 12 of 25 (48%) lobectomies. No MLNs were found in pneumothorax resections or pediatric autopsies. Patients ranged from 22 to 84 years (mean, 62), with only 4 younger than 40 years. There were 56 women and 25 men (female:male=2.2:1). The highest incidence of MLNs was in thromboembolic disease/infarcts (5/12; 42%) and respiratory bronchiolitis-associated interstitial lung disease/desquamative interstitial pneumonia (9/35; 26%). MLNs were randomly distributed in alveolar septa with no consistent relation to small blood vessels. Immunohistochemistry demonstrated positivity for CD56 (18/18) in addition to progesterone receptor (18/18), epithelial membrane antigen (11/11), and vimentin (2/2). The high incidence of MLNs in our study may be related to underlying chronic lung disease. The finding of MLNs in almost half of extensively sampled lobectomies suggests that they may be present in all abnormal lungs if sufficiently sampled. Their absence in infants and children indicates that they are not congenital rests. The positive staining for CD56 is novel, and as CD56 has been reported in meningiomas, this finding supports meningothelial differentiation.

Pulmonary Necrotizing Granulomas of Unknown Cause: Clinical and Pathologic Analysis of 131 Patients With Completely Resected Nodules

BACKGROUND The cause of pulmonary necrotizing granulomas is often unclear, even after histologic examination. Our aim was to determine the clinical significance of histologically unexplained necrotizing granulomas. METHODS Pulmonary necrotizing granulomas surgically resected at the Mayo Clinic (1994-2004) were retrieved and reviewed retrospectively. Cases in which a cause was evident at the time of initial histologic examination were excluded. The analysis cohort comprised 131 completely resected histologically unexplained pulmonary necrotizing granulomas. Clinical and laboratory information was abstracted from medical records, chest CT scans were reviewed, histologic slides were reexamined, and additional ancillary studies were performed in selected cases. RESULTS A cause was determined on review in more than one-half of the histologically unexplained necrotizing granulomas (79 of 131, 60%) by reexamining histologic slides (47), incorporating the results of cultures (26), fungal serologies (14), and other laboratory studies (eight), and correlating histologic findings with clinical and radiologic information (13). Infections accounted for the majority (64 of 79), the most common being histoplasmosis (37) and nontuberculous mycobacterial infections (18). Noninfectious diagnoses (15 of 79) were rheumatoid nodule (five), granulomatosis with polyangiitis (Wegener) (five), sarcoidosis (four), and chronic granulomatous disease (one). Many cases remained unexplained even after extensive review (52 of 131, 40%). Most of these patients received no medical therapy and did not progress clinically or develop new nodules (median follow-up, 84 months). CONCLUSIONS A cause, the most common being infection, can be established in many surgically resected pulmonary necrotizing granulomas that appear unexplained at the time of initial histologic diagnosis. Patients whose granulomas remain unexplained after a rigorous review have a favorable outcome. Most do not develop new nodules or progress clinically, even without medical therapy.

Biopsy findings in acute pulmonary histoplasmosis: unusual histologic features in 4 cases mimicking lymphomatoid granulomatosis.

Most examples of pulmonary histoplasmosis, including histoplasmoma and chronic histoplasmosis, are characterized by typical necrotizing granulomatous inflammation. Only disseminated histoplasmosis is recognized as causing a different reaction which consists of ingestion of organisms by macrophages without granuloma formation. The histologic features of acute pulmonary histoplasmosis are not well described as this form of the disease is rarely biopsied. We report the biopsy findings in 4 cases of acute pulmonary histoplasmosis, which seem to be unique to this form of Histoplasma infection. There were 3 men and 1 woman who ranged in age from 40 to 68 years. All presented acutely with fever and other flu-like symptoms. Radiographically, a solitary nodular infiltrate was present in 3 and bilateral reticulonodular infiltrates in one. Histologically, all 4 biopsies showed a nodular parenchymal inflammatory infiltrate composed of lymphocytes and histiocytes filling alveolar spaces and expanding the adjacent interstitium. Areas of parenchymal necrosis were additionally present in 3 cases. Vasculitis composed of lymphocytes and histiocytes was present in all, and was striking in 3, resulting in a resemblance to grade 1 lymphomatoid granulomatosis (LYG). Tip-offs to the correct diagnosis were small necrotizing granulomas scattered within the lymphohistiocytic infiltrate (3 cases), scattered histiocyte aggregates, and a few multinucleated giant cells. The diagnosis was confirmed in all by the presence of Histoplasma yeasts in Grocott methenamine silver-stained slides. Acute pulmonary histoplasmosis may cause a lymphohistiocytic infiltrate with necrosis and vasculitis that is suggestive of LYG. This observation emphasizes the importance of examining special stains for organisms before diagnosing grade 1 LYG.

RET-Rearranged Lung Adenocarcinomas with Lymphangitic Spread, Psammoma Bodies, and Clinical Responses to Cabozantinib

Abstract: Oncogenic rearrangements of the RET gene have recently been described in 1% to 2% of lung adenocarcinomas. We report five cases of RET-rearranged lung adenocarcinoma with an unusual constellation of clinical and histologic features that has not previously been described in tumors with this genomic alteration. The age at diagnosis of the five patients (4F, 1M) ranged from 44 to 77 years. All were never-smokers. Radiologically, four tumors showed lymphangitic spread within the lungs at presentation; three of these had multiple bilateral lung nodules. Histology showed psammoma bodies within the tumor in four of five cases. Molecular testing for activating EGFR mutations by standard genotyping and ALK expression by immunohistochemistry was negative in all cases. Additional molecular analysis was prompted by the clinical profile in that all five patients were never-smokers with metastatic, relapsed, and/or refractory disease; and also by unusual histologic findings in two cases. Comprehensive genomic profiling performed by means of a clinical grade cancer gene panel next-generation sequencing assay demonstrated a KIF5B-RET fusion in three; and fluorescence in-situ hybridization documented a RET rearrangement in two. Three of the patients were treated with the RET inhibitor cabozantinib. By Response Evaluation Criteria In Solid Tumors (RECIST) criteria, two had a confirmed partial response (at 6 weeks and 4 weeks) and one had stable disease. Our findings suggest that the combination of lymphangitic spread and psammoma bodies may be characteristic of a subset of advanced stage RET-rearranged lung adenocarcinomas. These findings should prompt additional molecular testing for RET translocations, particularly in never-smokers with EGFR- and ALK-negative lung adenocarcinoma.

Programmed Cell Death 1 (PD-1) Ligand (PD-L1) Expression in Solid Tumors As a Predictive Biomarker of Benefit From PD-1/PD-L1 Axis Inhibitors: A Systematic Review and Meta-Analysis

PurposeDrugs targeting the programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) pathway show significant clinical activity across several tumor types. However, a majority of patients do not respond to these agents. Use of biomarker assays to predict response to these agents is an active area of research; however, the predictive value of PD-L1 immunohistochemistry (IHC) assays is largely inconsistent across clinical trials. In this meta-analysis of clinical trials of PD-1/PD-L1–targeted agents, we evaluate the predictive value of a tumor and tumor-infiltrating immune cell PD-L1 IHC assay as a biomarker for objective response to PD-1/PD-L1 inhibitors.MethodsWe searched databases (PubMed, Medline, ASCO abstracts, European Society for Medical Oncology abstracts, and Scopus) up until December 2016 for clinical trials using PD-1/PD-L1 inhibitors with reported PD-L1 biomarker data. Objective response rates (primary end point) from all phase I to III trials investigating nivolumab, pembrolizumab,...

Visibility of Histoplasma within histiocytes on hematoxylin and eosin distinguishes disseminated histoplasmosis from other forms of pulmonary histoplasmosis.

The visibility of Histoplasma within histiocytes on hematoxylin and eosin is a well-known feature of disseminated histoplasmosis. However, it is unclear whether this finding can be used to differentiate disseminated histoplasmosis involving the lung from other forms of pulmonary histoplasmosis. The aim of this study was to determine whether the visibility of Histoplasma within histiocytes on hematoxylin and eosin in lung biopsies suggests disseminated disease. Lung biopsies in which Histoplasma was identified were re-examined to determine whether organisms were visible within histiocytes on hematoxylin and eosin. Clinical findings were reviewed retrospectively to determine the type of histoplasmosis. Histoplasma was visible within histiocytes on hematoxylin and eosin in lung biopsies from 4 patients (2 men, 2 women, 50-74 years) who presented with pulmonary manifestations without definite evidence of disseminated disease at the time of biopsy. Subsequently, all 4 manifested clinical and/or microbiologic features of disseminated disease (positive extrapulmonary cultures and fatal outcome in 2, positive extrapulmonary cultures in 1, and multiorgan failure and fatal outcome in 1). In contrast, organisms were identified on silver stains but could not be visualized on hematoxylin and eosin in 42 patients, none of whom showed clinical or microbiologic evidence of disseminated disease (pulmonary histoplasmoma, 38; acute pulmonary histoplasmosis, 4). In lung biopsies, the visibility of Histoplasma within histiocytes on hematoxylin and eosin suggests disseminated disease. Recognition of the significance of this finding is helpful in diagnosing disseminated disease in patients who present primarily with pulmonary manifestations without definite clinical evidence of dissemination at the time of biopsy.

Biopsy-site changes in lung adenocarcinoma with prior core needle biopsy: a potential pitfall in the assessment of stromal invasion.

Although biopsy-site changes are known to cause diagnostic difficulties in thyroid and breast specimens, especially when assessing invasion, such changes have not been described in the lung. Assessment of invasion is important in lung cancers to distinguish bronchioloalveolar carcinoma [adenocarcinoma in situ (AIS)] from invasive adenocarcinoma. The aim of this study was to determine whether biopsy-site changes occur in the lung and whether they may impact this differential diagnosis. Lobectomy specimens were examined from patients whose previous core needle biopsies showed well-differentiated adenocarcinoma with a lepidic pattern. There were 26 adenocarcinomas, including 14 minimally invasive adenocarcinomas, 2 invasive well-differentiated adenocarcinomas, and 10 AISs. Biopsy-site changes were identified in 9 of 26 (35%), including 4 minimally invasive adenocarcinomas, 3 AISs, and 2 well-differentiated adenocarcinomas. The interval between biopsy and resection ranged from 12 to 45 days (mean, 26.1 d). The biopsy sites consisted of a linear scar composed of collagen and plump fibroblasts, ranging from 2.0 to 13.1 mm in length and 0.5 to 1.6 mm in width. Scattered lymphocytes and plasma cells were present in 8 cases, pigment-laden macrophages in 4, and foreign body giant cells in 3. Benign entrapped lung epithelium was present within the scar in all 9 and entrapped malignant epithelium in 4. Biopsy-site changes can be identified in a significant proportion of lung tumors after core needle biopsy. They need to be distinguished from tumor-related stromal reactions that are considered an indication of invasion and are important in the differentiation of AIS and invasive adenocarcinoma.