Perivascular epithelioid cell tumor in the duodenum: challenge in differential diagnosis.

Defined as a family of scarce mesenchymal neoplasm which distinctively co-express melanocytic markers and muscle markers, perivascular epithelioid cell tumors (PEComas) have been reported almost everybody site. Perivascular epithelioid cell tumors-not otherwise specified (PEComas-NOS) arising in the gastrointestinal (GI) tract are still restricted into sporadic case reports. Herein we present a case of GI PEComas-NOS which occurs in the duodenum of a 27-year-old male. Our initial diagnosis tended to gastrointestinal stromal tumor or smooth muscle tumor till the correct diagnosis of perivascular epithelioid cell tumor (PEComa) was established by postoperative pathological examination. We also make a literature review of GI PEComas-NOS and highlight the challenge it brings to the differential diagnosis.