Endometriosis in the psoas major muscle: a case report

Endometriosis occurs outside the pelvic cavity is uncommon. To our knowledge, until now there is no case like this has been reported. A 49-year-old Chinese woman only with CA125 abnormal was admitted to our clinic. After a series of examinations, a mass in the left psoas major muscle was discovered. Based on the clinical symptoms, serologic markers and imaging features, we still could not rule out the possibility of malignant tumor. Finally, a diagnosis of endometriosis was made based on intraoperative pathological findings. Then she received relevant treatment. Three months later, both the lesion size and CA125 level decreased obviously. Retrospectively analysis of the disease progression, we find that rare cases like this not only enrich the location spectrum of endometriosis, but also help us gain more insight into the pathogenesis of it.