[Pulmonary malignant perivascular epithelioid cell tumor mixed with lung adenocarcinoma components: a case report and literature review].

Objective: To analyze the pathogenesis, clinical manifestations, diagnosis, treatment and prognosis of pulmonary malignant perivascular epithelioid cell tumor (PEComa) with adenocarcinoma. Methods: In August 2020, the Department of Pathology, Dongguan People's Hospital of Southern Medical University, diagnosed a case of pulmonary malignant PEComa mixed with adenocarcinoma. The clinical data, pathological diagnosis, treatment plan and prognosis of the patient were analyzed, and the literature was reviewed. Firstly, "malignant perivascular epithelioid cell tumor"+" Pulmonary "+"adenocarcinoma" was used to search CNKI and Wanfang Medical Database, but no relevant reports were found. Then, we changed the search term as "pulmonary malignant perivascular epithelioid cell tumor", and search for PubMed, Embase, Web of Science and Cochrane by combining the subject terms with "pulmonary malignant perivascular epithelioid cell tumor" and "PEComa" as subtopics. The language was Chinese or English and the search deadline was November 2020. Results: The patient, a 46-year-old male, was admitted to the hospital on August 20, 2020, due to "repeated cough and chest pain for more than 10 days, accompanied by rapid weight loss". Serology detected increased expression of lung non-small cell lung cancer related antigens. PET-CT showed a large mass of soft tissue density in the left thoracic cavity with an SUV value of 22.8. The postoperative pathological diagnosis was malignant PEComa mixed with adenocarcinoma and the lymph nodes were metastasized. Due to the detection of EGFR sensitive mutation, postoperative chemotherapy and targeted therapy were administered, and the current state was stable. A total of 12 cases of pulmonary malignant PEComa were retrieved in the literature, which were common in middle-aged and elderly people. They usually presented with cough or chest tightness. Chest CT mostly showed round masses with clear boundaries, and 8 cases had metastasis to mediastinal lymph nodes and other organs. Conclusions: Pulmonary malignant PEComa is rare. It is the first report of the same mass with lung primary adenocarcinoma. The tumor progresses rapidly. Complete surgical resection of the lesion and lymph node dissection are more appropriate treatment strategies, supplemented by postoperative chemotherapy and targeted therapy. For cases diagnosed as pulmonary PEComa, long term follow-up should be performed, even if the pathological diagnosis is benign.