Cerebellar Hypermetabolism in a Hodgkin Lymphoma Leads to Diagnosis of Paucisymptomatic Cryptococcus neoformans Meningitis.

Malignancy-associated cerebellar hypermetabolism on [18F]FDG PET/CT has 2 major causes: paraneoplastic autoimmune encephalitis and neoplasias (leptomeningeal/cerebellar metastases and primary cerebellar tumors). We present the case of a 33-year-old man with a newly diagnosed Hodgkin lymphoma and mere episodical headache, unexpectedly displaying intense cerebellar hypermetabolism on his staging [18F]FDG PET/CT. Both neurolymphomatosis and paraneoplastic subacute cerebellar degeneration were ruled out by clinical presentation, MR, and repeated lumbar punctures. Instead, cerebrospinal fluid analysis unveiled a Cryptococcus neoformans meningitis, highlighting the possibility of paucisymptomatic central nervous system infections as differential diagnosis in malignancy-related cerebellar hypermetabolism in addition to (para)neoplastic causes.