Endometriosis of Right Inguinal Subcutaneous Tissue

Endometriosis is usually found in intrapelvic structures such as ovaries, pelvic peritoneum and Douglas pouch. We report an unusual case of endometriosis in the right inguinal region. A 45-year-old Japanese woman complained of pain and a mass in the right inguinal region, and her symptoms fluctuated with the menstrual cycle. A poorly defined and elastic hard mass was palpable in the right inguinal region. Magnetic resonance imaging (MRI) showed mass in front of the pubis measuring 2 × 1 cm at the lower edge of the rectus abdominis muscle. We performed an excisional biopsy and pathological diagnosis was endometriosis. After the operation, she was relieved from pain and did not show any recurrence at the latest follow-up 30 months after the surgery. In patients with an inguinal subcutaneous mass complaining of periodic change of symptoms, endometriosis should be considered as a differential diagnosis. Since endometriosis can show variable signals on MRI, histological examination including biopsy is mandatory. J Med Cases. 2016;7(3):98-101 doi: https://doi.org/10.14740/jmc2428w