Small cell mesothelioma: A rare entity and diagnostic pitfall mimicking small cell lung carcinoma on fine‐needle aspiration Yanhong Zhang, Alaa Afify, Regina F. Gandour‐Edwards, John W. Bishop, Eric C. Huang Diagnostic Cytopathology.2016; 44(6): 526. CrossRef
A Biphasic Pleural Tumor with Features of an Epithelioid and Small Cell Mesothelioma: Morphologic and Molecular Findings Sarah Hackman, Richard D. Hammer, Lester Layfield Case Reports in Pathology.2016; 2016: 1. CrossRef
We report 4 cases of malignant thymoma which were composed of 2 cases of invasive thymoma and 2 cases of thymic carcinoma. The cytologic findings of invasive thymoma were similar to those of benign thymoma. The distinctive cytologic features of thymic carcinoma were necrotic background, irregular clusters and individually scattered arrangement of anaplastic epithelial cells, and some scattered mature small lymphocytes. These findings may be found in the Hodgkin'slymphoma, seminoma, and metastatic squamous cell carcinoma, undifferentiated carcinoma, and large cell carcinoma of the. lung. But, the feature of irregular clustering of anaplastic epithelial cell having scanty cytoplasm was different from Hodgkin'slymphoma and seminoma. Clinical and radiologic findings as well as cytologic finding were helpful in differential diagnosis of thymic carcinoma from metastatic carcinoma.
Well differentiated thymic carcinoma(WDTC) was recently separated from cortical thymoma. It is characterized by a predominance of epithelial cells with usually low mitotic rate, an epidermoid differentiation with slight to moderate cytologic atypia and lobular growth pattern. In recent reports, an uncommon spindle cell variant of WDTC, which is composed of spindle shaped epithelial cells, has been described. We investigated an unusual case of WDTC consisted of purely spindle shaped epithelial cells in a 66-year-old female. Radiologically, the well demarcated mass was located in the anterior mediastinum with focal invasion into the surrounding left upper lung. The tumor, 10 x 8 x 5 cm, was encapsulated with thin fibrous tissue and showed a pale yellow solid and lobulated cut surface. Microscopically, it consisted of solid sheets of purely spindle shaped epithelial cells with mild atypism, a low mitotic rate and focal epidennoid differentiation.
BACKGROUND The clinicopathologic features of thymic epithelial tumors are inadequate as predictors of the progression of these tumors because of their heterogeneous histology and varied biological behavior. We attempted to detect the expression of tyrosine kinase receptors and oncogenic markers to determine the correlation between these markers and the WHO classification of the tumors. METHODS: Forty-three surgically resected thymic epithelial tumors (37 thymomas and 6 thymic carcinomas) were immunohistochemically assessed on tissue arrays for c-KIT, her-2/neu, epidermal growth factor receptor (EGFR), p53. bcl-2 and Ki-67. RESULTS The Ki-67 labeling index was significantly increased in thymic carcinoma (p<0.05). The overexpression of p53 protein was observed exclusively in type B3 thymoma (67%) and thymic carcinoma (83%). Bcl-2 was expressed in type A and AB thymomas as well as in thymic carcinoma. C-KIT was only present in thymic carcinoma (p<0.05), whereas the EGFR expression was significantly high in all types of thymomas, except for thymic carcinomas. Her-2/neu was not identified in any type of thymoma. CONCLUSION: This study suggests that the Ki-67 LI, bcl-2, p53, c-KIT, and EGFR protein expression may be useful markers for the subclassification of thymic epithelial tumors according to WHO schema and WHO classification correlated with the tumor staging. The overexpression of c-KIT in thymic carcinoma reveals that these patients would likely benefit from an anti-c-KIT treatment.