Granulomatosis With Polyangiitis as an Etiology of Silent Sinus Syndrome: A Case Report.

Silent sinus syndrome (SSS) is a rare condition characterized by the collapse of the maxillary sinus and the sinking of the eye socket (enophthalmos). Only around 100 cases of SSS have been reported so far. The underlying cause of this condition is the chronic obstruction of the osteomeatal complex, which leads to sinus contraction. In this case, we present a novel finding linking SSS with granulomatosis with polyangiitis (GPA). The patient described is a 39-year-old male who was diagnosed with SSS after a prolonged period of sinus pressure, headaches, epistaxis, and generalized congestion. Additionally, the patient reported a significant autoimmune history, including a previous occurrence of ANCA-mediated glomerulonephritis. Surgical intervention revealed the presence of significant granulation tissue, while histopathological examination identified areas of necrosis, vasculitis, and multinucleated giant cells consistent with GPA. This finding was further supported by the detection of positive blood c-ANCA. This case is particularly noteworthy as it is the first reported instance of GPA causing SSS. It serves as an excellent example to illustrate the underlying pathophysiology of SSS.