A Patient with an Intradural Tumor: An Unexpected Finding.

Chronic back pain patients may require escalating doses of systemic opioids. In refractory cases, implantation of an intrathecal drug delivery system (IDDS) may provide effective relief of pain and improve overall function. This system infuses opioid directly into the cerebrospinal fluid via a catheter. While efficacious, it can be associated with complications, one of the most severe being the formation of a catheter-tip granuloma that can lead to permanent neurological deficits. We present a case of a 38-year-old male with an IDDS for pain related to retroperitoneal fibrosis, who began developing worsening back pain along with new-onset lower extremity weakness. A catheter-tip granuloma was suspected, and the patient was advised to obtain emergent spine imaging. He was non-compliant until the point of becoming wheelchair bound, whereupon imaging was finally obtained. Magnetic resonance imaging revealed an intradural mass causing spinal cord compression. After emergent surgical resection, pathology revealed a malignant tumor. Any patient with IDDS and escalating pain levels or new neurological deficits needs urgent neuroimaging to rule out catheter-tip granuloma. However, as this case demonstrates, the differential diagnosis should remain broad and always include neoplasm or abscess.