984 - Radicular symptoms in a 72-year-old male leading to unexpected new cancer diagnosis

Case Diagnosis: Right-sided lumbar radiculopathy due to sacral ala mass from metastatic prostate cancer

Case Description: A 72-year-old male with benign prostatic hyperplasia presented with 3 weeks of pain and paresthesia radiating from right buttocks down lateral leg and foot without preceding injury. Symptoms were constant without exacerbating factors and improved slightly with Medrol Dosepak, NSAIDs, and chronic suboxone. Physical exam demonstrated full thoracolumbar range of motion with painful flexion. There was tenderness to palpation over right lumbosacral junction but none throughout midline lumbar spine. Provocative maneuvers for sacroiliac and hip joint pain were negative. He had mild weakness in right great toe extension and diminished sensation in right L5 dermatome with fully intact reflexes. Clinical presentation was felt to be consistent with right L5 radiculopathy. Prior x-ray showed degenerative disc disease at L5-S1. Lumbar spine MRI was ordered and demonstrated right sacral ala mass. Further work-up culminated in surgery for sacral mass excision and right S1-S3 laminectomy, with pathology confirming diagnosis of metastatic prostate cancer.

Discussions: The patient’s radiating pain/numbness in a dermatomal pattern and mild weakness in the corresponding myotome are classic symptoms of lumbar radiculopathy, commonly caused by disc herniations and spinal stenosis. Other etiologies can present similarly, including extraspinal musculoskeletal conditions, vascular insufficiencies, peripheral neuropathies, autoimmune disorders, and in this case, tumors. Bone metastases are a major cause of pain in malignancy, with complex and varied pathophysiology often involving both cancer-induced bone pain and neuropathic pain related to infiltration/compression of neurologic structures.

Conclusions: This case demonstrates the importance of a broad differential for patients with classic symptoms of radiculopathy. Despite lack of significant evidence for malignancy or other rare etiologies, advanced imaging led to new cancer diagnosis and initiation of appropriate work-up and treatment.