A rare case of Castleman's disease presenting as a pulmonary mass mimicking pulmonary malignancy

Castleman disease is a rare disorder of the lymphoid system characterized by noncancerous growths that may develop in lymph node tissues throughout the body. Most often this occurs in the neck, mediastinum, and abdomen where lymph nodes aggregate. The etiology is thought to be due to antigenic hyperstimulation of unknown origin. Two histological subtypes are described with different clinical presentations and therapeutic implications. Diagnosis is frequently accomplished only by histological analysis after surgery since no specific features have been found in imaging studies. Surgical excision is both diagnostic and curative in localized forms, whereas additional therapies are required in multicentric forms. Here we describe a case of castleman disease adjacent to the right pulmonary hilum loosely adherent to the interlobar branch of the right pulmonary artery that mimicked tuberculosis or malignancy in a 30-year-old man who underwent curative surgical removal of the mass. Keywords: Castleman disease; Pulmonary malignancy; IL-6; HHV-8; Kaposi sarcoma DOI: 10.3126/jpn.v1i1.4456 Journal of Pathology of Nepal (2011) Vol.1, 63-65

Microcystic meningioma mimicking pleomorphic xanthoastrocytoma

Microcystic meningioma is a distinct morphological variant of meningioma, characterized by loose texture and microcysts with formation of large extracellular spaces containing edematous fluid. The tumor cells have stellate and vacuolated cytoplasm with long cytoplasmic processes. We report a case of microcystic meningioma occurring in a 60 year-old man. Histological features showed tumor cells with abundant foamy cytoplasm, pleomorphic nucleus with vesicular chromatin and prominent nucleoli which mimicked pleomorphic xanthoastrocytoma. The clinical presentation and histopathological diagnostic dilemma along with immunohistochemistry is discussed. Keywords: MicrocysticMeningioma; Pleomorphic xanthoastrocytoma Immunohistochemistry DOI: http://dx.doi.org/10.3126/jpn.v1i2.5413 JPN 2011; 1(2): 158-160

Role of immunohistochemistry in the diagnosis of malignant small round cell tumors

Background: Immunohistochemistry is a key tool for the analysis of localization of target molecules within tissues. It has a significant role in the identification of tumors lacking evidence of lineage differentiation on the basis of routine light microscopic morphology alone. Approximately 90% of tumors posing diagnostic difficulties by morphology could be accurately classified by exploiting immunohistochemistry. The aim of this study is to identify the true identity of malignant small round cell tumors by immunohistochemical analysis. Materials and Methods:This was a retrospective study done in Department of Histopathology of B.P.Koirala Memorial Cancer Hospital from January 2010 to April 2011.A total of 40 cases small round cell tumors were selected for immunostaining. The immunohistochemistry technique used is the Polymer detection-EnvisionTM System, a two step staining technique based on Horse Radish Peroxidase labeled dextran polymer technology (DAKO Company). Results: Out of 40 cases of malignant small round cell tumors, there were 21 cases (52.5%) of Non- Hodgkin Lymphoma , 11 cases (27.5%) of Ewing’s Sarcoma/Primitive Neuroectodermal Tumor, 1 case (2.5%) of Lymphoblastic Lymphoma , 1 case (2.5%) of Rhabdomyosarcoma, 2 cases (5%) of Low grade neuroendocrine tumor, 1 case (2.5%) of Neuroblastoma, 2 cases (5%) of Poorly differentiated Synovial Sarcoma (small cell variant), 1case (2.5%) of Malignant Melanoma (small cell variant). Conclusion: Immunohistochemistry is a valuable adjunct to routine hematoxylin and eosin staining for adequate and accurate categorization of malignant small round cell tumors. Keywords: Immunohistochemistry; Malignant Small Round Cell Tumor; Non Hodgkin’s Lymphoma; Ewing’s Sarcoma; Rhabdomyosarcoma DOI: http://dx.doi.org/10.3126/jpn.v1i2.5398 JPN 2011; 1(2): 87-91