IMAGE OF THE MONTH

A 41-year-old woman presented with dysmenorrhea. Inaddition, she described having catamenial left-sided sciatica and leg weakness for two years. During an earlier neurological assessment, she had been found to have a small left sided L5-S1 disc herniation on MRI, but this was felt not to be causing her symptoms. On examination a 2 cm nodule was palpable superior and lateral to the left ischial spine. At laparoscopy this nodule was found encased in the left pararectal space (Figure). Using the CO2 laser, the nodule was circumscribed and resected with other foci of endometriosis. At her postoper-ative visit, the patient was pain free. Histological assessment confirmed endometriosis in the nodule. Sciatica is a rare presenting symptom of endometriosis. The average delay to diagnosis is 3.7 years.1 Two-thirds of cases are right-sided.2 Possible etiologies include cyclic inflamma-tion and hemorrhage of pelvic peritoneal pocket endometriosis with resultant perineural fibrosis,3 or referred pain from endometriosis of the posterolateral pelvic peritoneum.4 Regardless, neurological sequelae may be permanent if the cause is not recognized and treated expeditiously. Consent to publish these images has been obtained from the patient.