IgG4-related disease involving distinctive areas of skull base: our experience.

BACKGROUND: Immunoglobulin G4-related disease (IgG4-RD) is a rare, systemic fibro-inflammatory condition characterized by lymphoplasmacytic infiltration with IgG4-positive plasma cells, storiform fibrosis, and elevated serum IgG4 levels. It can affect multiple organ systems, often mimicking malignancies or infections. Skull base involvement in IgG4-RD is uncommon and presents diagnostic and therapeutic challenges. We present three topographically distinct areas of skull base involvement patterns in IgG4-RD.

CASE PRESENTATION: This case series describes three patients with IgG4-RD affecting distinct skull base regions. The first case involves a 57-year-old female presenting with chief complaint of headache, sudden deterioration of vision in the right eye over the past two months, with ptosis and saddle nose deformity. Imaging revealed a heterogeneous multiloculated cystic lesion in intraconal compartment of right orbital apex with polypoidal mucosal thickening in ethmoid and sphenoid sinus. Biopsy done from posterior ethmoid and sphenoid mass confirmed IgG4-RD. The patient improved with corticosteroid therapy. The second case is a 50-year-old male with right-sided ear pain, decreased hearing, hoarseness of voice and facial nerve palsy for 3 months. Imaging showed a heterogeneous, enhancing soft tissue lesion involving right parotid, carotid, masticator, parapharyngeal and pharyngeal mucosal space with few lytic lesions involving petrous part of right temporal bone with adjacent sclerosis. Biopsy from nasopharynx confirmed IgG4-RD and corticosteroid therapy led to clinical improvement. Our third case is a 60-year-old male with IgG4-RD Oof nasopharynx, nasal obstruction and discharge for 3 months. Imaging revealed an ill defined soft tissue thickening in nasopharynx, bilateral Fossa of Rosenmuller and disease spreading to clivus. Biopsy from nasopharynx confirmed the diagnosis and patient started on oral corticosteroids, initially improved but the disease progressed, leading to multiorgan failure and death.

CONCLUSION: These cases highlight the diverse clinical presentations and outcomes of IgG4-RD involving the skull base. Early diagnosis through histopathology and initiation of corticosteroid therapy is critical for improving outcomes. However, refractory cases may require immunosupressive therapies.