Pudendal Tumor Mimicking Cauda Equina Syndrome and Acute Radiculopathy: Case Report.

Introduction Cauda equina syndrome (CES) is most caused by lumbar disc herniation, and the associated treatment involves prompt surgical decompression. Rarer causes of CES include perineural (Tarlov) cysts. Clinical presentation A 62-year-old female with history of rheumatoid arthritis, hip and knee replacements, and chronic low back pain presented with worsening back pain, left leg weakness and pain for 6 weeks, and bowel/bladder incontinence with diminished sensation in the perianal region for 24 h prior to presentation. MRI demonstrated severe spinal stenosis at L4-S1, central disc herniation at L5-S1, and compression of the cauda equina, consistent with CES. A lumbar decompression was performed. Patient did well at 2-week follow up, but presented 5 weeks post-discharge with increased left leg pain/weakness and genitalia anesthesia. Imaging was unremarkable. Two months later, the patient presented with diminished sensation in the buttocks and bilateral lower extremities and bowel/bladder incontinence. Imaging demonstrated a large cystic presacral mass with involvement of the left sciatic foramen and S3 neural foramen. A team of plastic, orthopedic, and neurological surgeons performed an S3 sacral laminectomy, foraminotomy, partial sacrectomy, and S3 rhizotomy, and excision of the large left hemorrhagic pudendal mass. Final pathology demonstrated a perineural cyst with organizing hemorrhage. On follow-up, the patient's pain and weakness improved. Conclusion CES-like symptoms were initially attributed to a herniated disk. However, lumbar decompression did not resolve symptoms, prompting further radiographic evaluation at two separate presentations. This represents the first reported case of a pudendal tumor causing symptoms initially attributed to a herniated disc.