Obturator mononeuropathy caused by pelvic cancer: six cases.

ABSTRACT

OBJECTIVE: To report the clinical and pelvic CT findings in six patients with obturator mononeuropathy caused by cancer. DESIGN: A clinical case series of six patients followed for 2 months to 10 years (one patient lost to follow-up). SETTING: Three referral centers. PATIENTS Three men and three women, ages 52 to 81 years. Three patients had transitional cell carcinoma of the bladder, and one patient each had pelvic papillary carcinoma, carcinoma of unknown origin, and lymphoma. MAIN RESULTS: In each patient, symptoms of obturator mononeuropathy were the sole presenting sign of new or recurrent pelvic cancer. Three patients had ipsilateral leg edema in addition to the typical sensory and motor findings of obturator mononeuropathy. Tumor sites detected on pelvic CT that correlated with obturator nerve compression or infiltration, singly or in combination, included the posterolateral wall of the upper pelvis or midpelvis, the anterior wall of the lower pelvis, and the external obturator and pectineus muscles extrinsic to the bony pelvis. Antineoplastic treatment provided symptomatic relief in four patients. CONCLUSIONS: Pelvic CT or MRI should be performed to exclude pelvic tumor in patients with obturator mononeuropathy if there is no temporal association with pelvic trauma or intra-abdominal, pelvic, or hip surgery.