PMC4336393_01
(A) Gross findings on Nephrectomy specimen: large well-delineated, nodular, tan- brown colored tumor nearly completely replacing the normal renal parenchyma. (B) H and E10x (C) H and E 20x: biphasic population of cells, large epitheloid cells with voluminous eosinophillic cytoplasm and smaller cells with much lesser amount of cytoplasm and small rounded nuclei. (D) The smaller cells at places clustered around hyaline pink material forming "pseudorosettes".
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Bisected kidney showed a large well-delineated, nodular, tan- brown colored, soft to firm tumor measuring 13.7 x 11.0 x 8.0 cm, nearly completely replacing the normal renal parenchyma (Fig 1A). Morphology revealed a biphasic population of cells (Fig 1B and C), large epitheloid cells with voluminous eosinophilic cytoplasm and smaller cells with much lesser amount of cytoplasm and small rounded nuclei. The smaller cells at places clustered around hyaline pink material forming "pseudorosettes"(Fig 1D).
Immunohistochemistry: (A-C) pan CK, EMA and TFE3, respectively. Immunonegative for pan CK, EMA and TFE3. Note nuclear nonreactivty for TFE3. (D) HMB45 and (E) Melan A. Immunopositivity for HMB45 and Melan A.
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Immunohistochemically (Fig 2A-E) both types of tumor cells showed negativity for pan CK (cytokeratin), EMA (epitheleal membrane antigen) and TFE3 (transcription factor E3).