Malignant perivascular epithelioid cell tumor (PEComa) is a rare tumor composed of hybrid tumor cells characterized by immunoreactivity for both melanocytic and smooth muscle markers. This paper describes the uncommon esophageal location of an 8 cm PEComa in a 75-year-old Caucasian man who was presented with ingravescent dysphagia. Although PEComas arising within the gastrointestinal tract are ...

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...

Leiomyosarcoma of the uterus is a malignant tumor arising from the smooth muscle of the uterus. It is a rare tumor with an incidence as low as 2%-5% of all uterine malignancies. Besides the conventional type, one of the important variants includes the epithelioid leiomyosarcoma which is by itself a rare subtype of leiomyosarcoma. The precise diagnosis of leiomyosarcoma is essential since it has...

INTRODUCTION Typical angiomyolipoma (AML) is a benign neoplasm, which consists of a mixture of smooth muscle, fat, abnormal blood vessels, and perivascular epithelioid cells, the latter of which have been described to be present in varying proportions. Recent reports have described renal masses comprised almost entirely of perivascular epithelioid cells and have designated them as “monotypic ep...

BACKGROUND Angiomyolipoma is a benign mesenchymal tumor composed of variable amounts of smooth muscle, adipose tissue and thick-walled blood vessels, and usually named PEComas (perivascular epithelioid cell tumors). PEComas share overlapping histopathological features with epithelioid cells along a perivascular distribution and characteristic immunohistochemistry with coexpression of myoid and ...