Deceptive Features on Surveillance Imaging of Intraneural Metastatic Deposits in Metastatic Renal Cell Cancer

BACKGROUNDSpinal renal cell metastases are a common insidious pathological manifestation of the oncological process but less common are intramedullary and intraneural spinal metastases. The differential diagnosis of such pathological features can be difficult in the presence of conflicting radiological evidence. CASE DESCRIPTIONIn the present case report, we have detailed the clinical, diagnostic, surgical, and therapeutic progression of a 54-year-old man diagnosed with metastatic renal cell carcinoma. After the initial presentation and treatment, he had presented with symptomatic right lower limb radiculopathy. Magnetic resonance imaging identified a well-defined cystic lesion expanding in the right exit foramina at L5-S1, suggestive of a benign schwannoma. After a multidisciplinary review, he was treated symptomatically and imaging surveillance for a 19-month period, with static lesion findings. Failure of symptomatic management resulted in operative intervention and subsequent histological diagnosis of the metastatic deposit. CONCLUSIONTo the best of our knowledge, the present report is the first documented case of intraneural metastatic deposits from renal cell carcinoma that showed benign radiographic features and demonstrated a stable appearance on surveillance imaging studies for a significant period. These findings suggest that clinicians should have a high index of suspicion for a metastatic process in symptomatic patients with a known renal cell cancer regardless of the lesion's radiographic or temporal characteristics.