Malignant perivascular epithelioid cell tumor arising in the mesentery: A case report

Abstract

We report a rare case of primary malignant PEComa arising in the mesentery. A 35-year-old male patient with medical history of papillary thyroid carcinoma and chronic hepatitis B virus infection, presented with periumbilical abdominal pain. Upon physical and imaging exploration, a mesenteric mass was detected. The patient underwent tumor resection surgery. Thirteen months postsurgery, the disease recurred in multiple mesenteric masses leading to bowel obstruction complication. The tumor's characteristics, including its precise location, size, invasive nature, and metastatic lesions were fully documented on CT-scan/MRI reports. The patient subsequently had a second surgery to remove the extensively invasive obstructive lesion and to restore gastrointestinal
continuity. Histopathological analysis confirmed the diagnosis of primary malignant PEComa of the mesentery. PEComas is more common in women than men and typically occurs between the ages of 45 and 55. These tumors originate from perivascular cells and can develop in various locations throughout the body. The clinical symptoms and laboratory findings of PEComa are nonspecific, and there are are no typical imaging patterns to identify them. PEComa is definitively diagnosed by histopathology, which demonstrates a tumor with differentiation features of both smooth muscle and melanocytic cells. The malignant behavior of PEComa is determined by the presence of invasion, metastasis on clinical examination as well as highrisk histologic features. For localized PEComas, the most effective treatment is radical tumor resection surgery. In the case of locally advanced or metastatic disease, where radical surgery is no longer feasible, targeted therapies with mTOR inhibitors are effective and have been incorporated into current treatment guidelines. Further researches are needed to elucidate the pathogenesis of PEComa and develop novel therapeutic strategies.