Successful rituximab treatment of granulomatosis with polyangiitis with cranial neuropathies

Background: In granulomatosis with polyangiitis (GPA), peripheral nerve involvement is common but central nervous system (CNS) involvement is extremely rare and treatment strategy has not been established. We report a case of intravenous cyclophosphamide (IVCY)-resistant GPA with associated cranial neuropathies that was successfully treated with rituximab (RTX). Case presentation: A 37-year-old man with intractable sinusitis had several months of headache, hoarseness, and dysphagia; a month of right-sided deafness and nasal bleeding; and a week of dysarthria, steppage gait, and numbness in the right L5 distribution. A magnetic resonance imaging (MRI) examination of the head showed an infiltrative lesion in the right skull base encasing the carotid sheath. Computed tomography (CT) scan of the chest revealed a 23 mm nodule in the left upper lobe. Histology was inconclusive. Therefore, the patient was diagnosed as GPA. He was treated with glucocorticoids (GC) and IVCY. Three months later, he was readmitted for recurrence of headache and new left-sided hearing loss. He was treated with GC and RTX, and a 1-year remission followed. The molecular mechanism of RTX is not fully understood. In this case, RTX was more effective at rapidly and strongly suppressing B cells than CY. Since the B cell count was proportional to the patient's clinical manifestations, B cells might represent a suitable target for the treatment of GPA with cranial neuropathies. Conclusions: GPA with cranial neuropathies might be useful with RTX as induction therapy.