&NA;Basaloid squamous cell carcinoma is a high‐grade, aggressive variant of squamous cell carcinoma with a predilection for the larynx, hypopharynx, tonsils, and base of the tongue. It has rarely been reported in the sinonasal region. A 75‐year‐old woman had a mass in the left ethmoid sinus. She had a history of olfactory neuroblastoma of the nasal cavity diagnosed 6 years previously. The following case highlights the clinical and pathologic features of basaloid squamous cell carcinoma and emphasizes the broad differential diagnosis of this lesion as it presents in the sinonasal region.