mTOR inhibitor in the treatment of TFE-positive advanced maligmnant PEComa of the uterus: a case report and literature review.

BACKGROUND: The pre- and intra-operative diagnoses of malignant uterine vascular perivascular epithelioid cell tumors (PEComas) can be challenging, for which the literature is limited. Some cases have been shown to have TSC gene mutations or rearrangements of the MiT factor family, resulting in variable responses to mTOR inhibitors. We report a case of a TFE-positive malignant PEComa of the uterus with pulmonary metastases that responded favorably to the mTOR inhibitor, everolimus.

CASE PRESENTATION: A 52-year-old female underwent a total hysterectomy 5 years ago for suspected sub-serosal or broad ligament fibroids. The intraoperative pathologic diagnosis was leiomyosarcoma of the uterus and the postoperative diagnosis was malignant PEComa of the uterus. The patient declined genetic testing and further treatment. In December 2020 the patient presented with a pelvic mass and underwent open abdominal mass resection and pelvic adhesiolysis. The pathologic findings confirmed recurrent malignant PEComa of the uterus. The pulmonary lesions gradually progressed during the follow-up period, so treatment with everolimus was initiated. Close follow-up evaluation for nearly 3 years showed disease remission without recurrence or progression.

CONCLUSION: The patient described herein had a TFE-positive uterine malignant PEComa with lung metastasis and responded well to the mTOR inhibitor, everolimus. Close follow-up in the last 3 years showed remission without recurrence or progression.