Objectives Malignant perivascular epitheliold tumors (PEComas) are rare mesenchymal tumors originating from perivascular epithelioid cells with specific histologic and immunologic features. Due to its rarity, lack of specific clinical findings, aggressive and unpredictable biologic behavior, this type of tumor is difficult to manage and there is no standard therapeutic strategy.

Methods A 34-year-old G1P1(1001) presented with a history of galactorrhea (elevated prolactin 313 ng/mL) and irregular menstruation. On work-up, cranial magnetic resonance imaging (MRI) revealed no mass on the pituitary gland, abdominopelvic MRI showed a large uterine mass. She was initially treated medically which offered no relief of symptoms. She was then diagnosed and managed as a case of ectopic prolactin secreting leiomyoma uteri. Myomectomy was performed and prolactin level decreased to normal level (6.3 ng/mL) and with resolution of symptoms. Histopathology revealed malignant PEComa. Prolactin increased when tumor recurred and she underwent re-exploration and tumor debulking. Specimen from first and second operation were compared and shared the same histomorphological features. Immunohistochemical stain for prolactin was performed because of the suspicion of ectopic prolactin secreting tumor but revealed a negative result. The patient was given 3 cycles of Doxorubicin.

Results Endocrine paraneoplastic syndrome is the production of hormonal substances that produce unique clinical syndromes, example is prolactin. Ectopic prolactin secretion is the production of hormone by a cell type that does not normally produce the hormonal substance or produces it normally at very low levels.

Conclusions The index case showed malignant PEComa of the uterus associated with hyperprolactinemia with negative immunohistochemical stain for prolactin.