The granulomas of sarcoidosis and non-caseating tuberculosis show similar cell-types: two forms of epithelioid cells, A and B, giant cells, lymphocytes and 'activated' mononuclear cells. The morphology of epithelioid cells suggests that they are primarily biosynthetic rather than phagocytic. The relationship of these various cells to each other is discussed and the following sequence of granulo...

Epithelioid hemangioendothelioma is a rare vascular tumor with cytologic behavior between angiosarcoma and hemangioma. We present the case of a 58-year-old male with primary epithelioid hemangioendothelioma of the distal radius measuring 6.2 × 5 cm with extension into the pronator quadratus and brachioradialis muscles. We discuss our approach to performing a limb-sparing resection combined with...

Primary malignant peripheral nerve sheath tumors(MPNST) of the vulva are extremely rare and most of them are composed of a spindle cell component. A few cases of MPNST containing partially or purely epithelioid cells have been reported. Purely epithelioid MPNST differ from the ordinary epithelioid MPNST due to the absence of a spindle cell component. We present the first case of purely epitheli...

Objective: Pigmented epithelioid melanocytoma was proposed by Zembowicz et al in 2004 including lesions previously diagnosed as human animal-type melanoma and epithelioid blue nevus. Tumors are composed of epithelioid and spindled melanocytes with heavy pigmentation. Methods: We report a case of pigmented epithelioid melanocytoma in 47-year-old Asian woman. The tumor sized 10 × 6 × 2 cm on the ...

tumors that originate from the nerve sheath comprise diverse groups -perineuroma, neurofibroma and schwannoma. the epithelioid variant of these tumors is uncommon and mostly seen in malignant counterparts. although this type of morphology is well recognized in peripheral nerve sheath tumors, its presence in the central nerves is rarely reported. very few cases of nerve sheath tumors have been r...

Perivascular epithelioid cells (PECs) were initially proposed, by Bonetti et al. in 1992, to describe an “unusual atypical cell type” of epithelioid shape and harboring a clear to eosinophilic cytoplasm with perivascular distribution in both renal angiomyolipoma (AML) and clear cell sugar tumor (CCST) of the lung. This perception gradually became accepted and led to the concept of perivascular ...

Epithelioid sarcoma represents less than 1% of soft tissue sarcomas and has a high recurrence rate and strong ability to invade the regional lymphatic pathways. Classic epithelioid sarcoma has a predilection for young men and usually affects the distal extremities, while the proximal-type is characterized by different histological features and most commonly occurs in the proximal part of the ex...

Investigations on nine different mammalian cell lines revealed that permanently growing cells of one morphological class have numerous membrane properties in common which are different or even lacking in the other cell class. With electrophysiological methods it is shown that the sensitivity of the Na<·K< pump to ouabain is three orders of magnitude higher in the ionically non· coupled epitheli...

Spontaneous thymoma was found in the left lobe of the thymus of a male 10-week-old Sprague-Dawley (SD) rat. Microscopically, the thymic mass showed a sheet of dark area with multiple pale foci. The dark area mainly consisted of densely compacted small lymphoid cells with sporadic large epithelioid cells and mitotic figures. The epithelioid cells and mitotic figures were more frequent than those...

We report a case of perivascular epithelioid cell tumor arising in the rectum of a 55-year-old woman. The tumor was treated by transanal endoscopic microsurgery. After 1 year follow-up, the patient is alive with no radiologic or endoscopic evidence of recurrence. Perivascular epithelioid cell tumor is a rare mesenchymal tumor characterized by co-expression of melanocytic and smooth muscle marke...