A malignancy phantom: a rare clinical case report of metastatic renal cell carcinoma with no evidence of a primary lesion presenting as cerebellar ataxia

Abstract

Background: Anti-Ma2 antibody-associated paraneoplastic syndrome (PNS) usually presents as limbic encephalitis in the context of testicular tumors. We report a rare case of anti-Ma2 positive PNS with deviation from the classic scenario, thus expanding the phenotype of anti-ma2 associated PNS. Case Presentation: This is a 53-year-old male who presented with dizziness and visual changes and was later diagnosed with anti-Ma2 antibody-positive cerebellar ataxia. Further workup revealed retroperitoneal lymphadenopathy which, using biopsy, was identified as metastatic clear cell renal cell carcinoma. However, imaging did not reveal a primary renal lesion. Conclusion: Physicians should be aware of non-classic presentations of PNSs, especially given that they commonly precede and point towards an underlying, many times undiagnosed, malignancy.