Renal Perivascular Epithelioid Cell Tumor with Lymph Nodes Metastasis: A Case Report and Literature Review

Background: Perivascular epithelioid cell tumor (PEComa) is mesenchymal tumor that originated from perivascular epithelioid cells. Angiomyolipoma (AML) is a common benign PEComa, composed of blood vessels, smooth muscle and mature adipose tissue. Epithelioid angiomyolipoma (EAML) is a rare subtype of AML that has the potential to be malignant.Case presentation: The patient was a 42-year-old woman admitted to the hospital for her left low back swelling. The computed tomography angiography (CTA) revealed a 6.3*5.5*6.7cm cystic-solid tumor in the intermediate kidney. Then we performed a left nephrectomy. Postoperative pathology showed that the tumor was angiomyolipoma (PEComa) with necrotic formation and was 6cm*6cm*5.5cm in size. Additionally, lymph nodes involved (4/17) were observed in the left renal hilum. Immunohistochemistry staining indicated that tumor cells focally expressed MelanA and HMB45. No evidence of disease progression at the six-month follow-up after surgery.Conclusions: Lymph nodes involvement in renal PEComa was rare and was regarded as a type of metastasis. Lymph nodes metastasis might indicate a poor prognosis.

Sustained response to pembrolizumab in recurrent perivascular epithelioid cell tumor with elevated expression of programmed death ligand: a case report

Background Perivascular epithelioid cell tumors are defined by the World Health Organization as “a collection of rare mesenchymal tumors composed of histologically and immunohistochemically distinctive perivascular epithelioid cells.” Whereas localized perivascular epithelioid cell tumor is typically benign and treated successfully with surgical resection, prognosis for patients with advanced or metastatic perivascular epithelioid cell tumor is unfavorable, and there is no standard curative treatment. Case presentation We report a Caucasian case of metastatic perivascular epithelioid cell tumor previously treated with chemotherapy and surgery with elevated surface expression of programmed cell death ligand 1. Based on this result, treatment via immune checkpoint inhibition with the monoclonal antibody pembrolizumab was pursued. After 21 cycles, the patient sustained a complete response. Therapy was stopped after the 40th cycle, and she was moved to surveillance. She remained disease free 19 months off treatment. Conclusions This case report of a patient with perivascular epithelioid cell tumor treated successfully with programmed cell death protein-1 targeted therapy suggests that programmed cell death ligand-1 levels should be measured in patients with perivascular epithelioid cell tumor and immunotherapy considered for recurrent or metastatic patients. Future phase II/III studies in this disease should focus on sequencing of surgery and immunotherapy with a design of curative intent.

Clinicopathological features and treatment of perivascular epithelioid cell tumor.

e23538 Background: Perivascular epithelioid cell tumor (PEComa) is a rare form of mesenchymal neoplasms. No clinical trial of large sample size regarding medical treatment of PEComa has been reported so far. Previous retrospective studies with small sample size have showed efficacy of mTOR inhibitors as treatment of PEComa. This study aimed to analyze the clinicopathological features of PEComa, and the efficacy of mTOR inhibitor in advanced PEComa. Methods: Medical information of patients diagnosed with PEComa and treated in Fudan University Shanghai Cancer Center were collected. Survival analysis was performed by Kaplan-Meier method. Radiological response was assessed according to RECIST version1.1. Results: A total of 17 patients were treated in our center during June 2007 to June 2020. PEComa mostly occurs in middle-aged women. The most common primary sites are pelvis, lung and abdomen. Relapse usually occurs within 2 years after radical surgery. Radical surgery is the main treatment for PEComa of limited stage, and remains the main option for those with limited recurrent lesions. Of the 13 patients with advanced malignant PEComa in our cohorts, the objective response rate of mTOR inhibitors in advanced malignant PEComa was 45.5%, and median progression-free survival was 27.7 months (95% CI 4.7-50.5 months). 2 patients discontinued mTOR inhibitor treatment due to pneumonitis combined with dyspnea and fever respectively. Conclusions: For advanced malignant PEComa, mTOR inhibitors are effective. Lung toxicity of mTOR inhibitor should be monitored.