Progressive encephalomyelitis with rigidity and myoclonus (PERM) associated with anti-glycine receptor antibodies and urothelial carcinoma: a case report

BACKGROUND: Progressive encephalomyelitis with rigidity and myoclonus (PERM) is a rare neurological condition with paraneoplastic etiology in about 20% of cases, usually presenting before or shortly after the oncological diagnosis is established. PERM associated with anti-glycine receptor antibodies is not previously reported in a patient with bladder cancer. CASE PRESENTATION: A 72-years-old Caucasian male was admitted with acute onset of dysarthria, dysphagia and trismus three years after initial surgical treatment for bladder cancer. The condition was initially diagnosed as tetanus and treated accordingly, but the diagnosis was reconsidered because of progression despite adequate treatment. Diagnostic workup on readmission revealed lung and paraaortal metastases from bladder cancer and anti-glycine receptor (anti-GlyR) antibodies both in the cerebrospinal fluid and in serum, which supplemented with the clinical presentation led to the diagnosis of PERM, presumably related to bladder cancer. The patient showed improvement and stabilization after treatment with intravenous immunoglobulin and chemotherapy against metastatic bladder cancer. CONCLUSION: To the best of our knowledge, this is the first reported case of anti-GlyR antibody positive PERM related to urothelial carcinoma. The symptoms mimicked tetanus, and responded to chemotherapy and immunotherapy.