Primary malignant gastric PEComa - Diagnostic and technical dilemmas.

INTRODUCTION: The World Health Organisation defines PEComa's as "a mesenchymal tumour composed of histologically and immunohistochemically distinctive perivascular cells".(1) These ubiquitous tumours show distinctive perivascular epithelioid cell differentiation and arise most commonly at visceral and abdominopelvic sites. PRESENTATION OF CASE: We present a case of a forty-two year old man presenting to accident and emergency department with upper gastro-intestinal bleeding. He had a palpable epigatric mass on examination. He underwent a CT Scan Abdomen which displayed a tumour arising from the gastric wall. Upper GI endoscopy and biopsy was carried out and biopsied were taken for histological analysis. A primary gastric PEComa was diagnosed and the patient underwent distal polya gastrectomy and gastrojejunostomy. This is believed to be the first reported case of a Primary malignant gastric PEComa. DISCUSSION: Perivascular epithelioid carcinomas were first described in 1943 as an abnormal myoblast in a case of renal angiomyolipoma. PEComas display a strong female predominance with a typical benign course. There are approximately 100 reported cases of PEComa to date, with 55 of which were malignant. PEComa's may be subdivided into benign, uncertain malignant potential and malignant. Their natural history can be very aggressive leading to multiple metastases and death as expected with a high-grade sarcoma.
CONCLUSION: This case depicts the aggressive nature of malignant gastric PEComa's. The majority of PEComa's are benign in nature and have a better prognosis. We display here the challenges in ascertaining a definitive diagnosis and management of such patients due to limited clinical studies.