Perineural Spread Along Spinal and Obturator Nerves in Primary Vaginal Carcinoma: A Case Report.

Background: Perineural spread is not an uncommon feature in carcinoma of the head and neck. On the contrary, perineural spread in pelvic malignancies has been rarely reported. This is the first report on perineural spread of the obturator nerve and the lumbosacral plexus from primary vaginal cancer.

Methods: A 50-year-old woman diagnosed with infectious spondylitis at an outside hospital was referred to our institution. She presented with persistent lower back pain and right anterior thigh pain. Magnetic resonance imaging and subsequent 18F-fluorodeoxyglucose-positron emission tomography/computed tomography revealed primary vaginal cancer with metastatic lymphadenopathy and perineural spread of the lumbosacral plexus, including L3, L4 nerve roots and branches, and obturator nerve along with soft tissue masses in the right psoas and proximal adductor muscles.

Conclusions: Clinical diagnosis of perineural spread in pelvic malignancies is difficult to establish, as it has nonspecific symptoms as an initial manifestation. Clinicians should recognize the possibility of perineural spread of malignancies if radiologic findings, such as thickening of lumbosacral nerves and perineural mass, are observed on magnetic resonance imaging. Further evaluation is necessary to detect possible pelvic malignancy and differentiate from other diseases.