Endometriosis of the lumbosacral plexus: report of a case with foot drop and chronic pelvic pain

Abstract

Endometriosis which affects 5–10 % of females at the reproductive age, is most often found in the pelvic cavity and this estrogen-dependent inflammatory disease is one of the prevalent causes of chronic pelvic pain [1]. One rare presentation of endometriosis is sciatic involvement, which presents as catamenial sciatica or foot drop [2, 3]. A 37-year-old nulliparous woman was referred to our clinic with a history of pelvic pain and right lower extremity associated with gait difficulty and recurrent right ankle sprains since 2 years. The pain became worse during menses. On the first assessment, there was muscle wasting and decreased deep tendon reflexes in right lower extremity. She was unable to perform the toe and heel walk test properly. During the motor strength examination, the hip flexion, foot dorsiflexion and plantar flexion were 4/5, 3/5 and 4/5 respectively. The big toe dorsiflexion and plantar flexion test were completely impaired. Slight hypoesthesia was detected in the medial aspect of the thigh (L1 and L2) and the posterior portion of the leg (S1). There were no fasciculations. Brain and panspinal MRI with and without contrast were normal. On transvaginal ultrasound, multiple leiomyofibromas were seen in the uterus. In addition to the multiple fibroids, several right ovarian cysts and asymmetries in the right sciatic region with an enhancing soft tissue in the sacrosciatic notch with thickening of the sciatic nerve were reported on CT scan and MRI of the pelvis. EMG-NCV was suggestive of partial involvement in the lumbosacral plexus. CSF analysis was within normal range without any malignant cells. Serologic findings for sarcoidosis, brucellosis, rheumatologic disorders, HIV, HBV, HCV, EBV, and CMV were negative. Due to unsatisfactory findings, we referred the patient to an expert laparoscopist to explore her pelvic cavity. During the laparoscopic procedure, because of severe mass effects of multiple myomas on the rectum and bladder, a hysterectomy was performed. Also, one of the ovarian cysts was resected from the right ovary, but no other masses were detected by the surgeon. The pathologic study revealed evidence of endometriotic cysts in the right ovary. Postoperatively, the pain decreased to some extent for 2 months, but again the patient experienced severe intractable pain in her pelvis and right lower extremity during expected menses and her gait became more abnormal. Repeat examination at 6 months revealed complete foot drop on the right side and a new EMG-NCV study showed progression in the lumbosacral plexus; therefore, we repeated a pelvic MRI which was diagnostic and showed a 4–4.5 cm lobulated lesion in the right sciatic notch involving the Sciatic nerve. M. Motamedi F. Mousavinia (&) Department of Neurology, Sina Hospital, Tehran University of Medical Sciences, Tehran, Iran e-mail: drsfmnia@gmail.com