A perivascular epithelioid cell tumor of the stomach: an unsuspected diagnosis

Abstract

Perivascular epithelioid cell tumor (PEComa) is a rare mesenchymal neoplasia and currently well recognized as a distinct entity with characteristic morphological, immunohistochemical and molecular findings. We report a case of PEComa arising in the antrum of a 71-year-old female with melena. The tumor, located predominantly in the submucosa as a well delimited nodule, measured 3.0 cm in diameter and was completely resected, with no evidence of the disease elsewhere. Histologically, it was composed predominantly of eosinophilic epithelioid cells arranged in small nests commonly related to variably sized vessels, with abundant extracellular material, moderate nuclear variation and discrete mitotic activity. No necrosis, angiolymphatic invasion or perineural infiltration was seen. Tumor cells were uniformly positive for vimentin, smooth muscle actin, desmin and melan A. Although unusual, PEComa should be considered in the differential diagnosis of gastric neoplasia with characteristic epithelioid and oncocytic features and prominent vasculature.

Figure 1

Low power view showing the tumor predominantly located in the submucosa with focal ulceration of the adjacent mucosa.

Figure 2

Microscopy showing the tumor cells mostly arranged as small nests commonly related to variably sized vessels, with abundant extracellular material and mucinous or collagenous characteristics.

Figure 3

Neoplastic cells showing eosinophilic and clear epithelioid characteristics and perivascular arrangement (A) and focal rhabdoid features (B).