Tumefactive fibroinflammatory lesion successfully treated with Rituximab

Skull base pseudotumors, or tumefactive fibroinflammatory lesions (TFIL), are tumors characterized by local destruction with benign histopathology. Treatment includes surgery and steroids with varying degrees of symptom relief. A 45-year-old female presented with right otorrhea and middle ear effusion, which progressed to CN V₃ pain/numbness, trismus, headache, and autophony. MRI showed a diffuse infiltrating mass in the right infratemporal region involving the trigeminal ganglion. Biopsy revealed benign fibromuscular and adipose tissue with lymphoplasmacytic infiltrate, giving a diagnosis of TFIL. Resection would be very difficult given tumor location. Initial treatment included an extended course of steroids without response, and interval disease progression. Two courses of rituximab 375 mg/m² weekly × 4 given 3 months apart were then completed with excellent tolerance. With sixteen months following induction, the patient reports minimal symptoms with radiographic findings confirming continued disease regression. Rituximab is a potential treatment option for patients with TFIL without response to steroids.