Metastatic uterine leiomyosarcoma and eosinophilia

Uterine sarcomas account for approximately 3% to 7% of all uterine malignancies. Distinguishing benign and malignant myomas based on physical examination and imaging alone is challenging.

A postmenopausal woman with a history of leiomyomas presented to the Emergency Department with chest pain and a right upper lobe lung mass. Blood tests demonstrated profound eosinophilia (58,000/mm). Positron emission tomography-computed tomography scan to exclude distant disease as work-up for presumed lung cancer revealed increased tracer uptake in the lung mass and a pelvic mass. The patient died from complications of hypereosinophilia, and a postmortem diagnosis of metastatic uterine leiomyosarcoma was made.

Significant blood eosinophilia is uncommon in leiomyomas and should raise suspicion of malignant etiology for a pelvic mass.