Squamous cell carcinoma
Sinonasal squamous cell carcinoma (SCC) or epidermoid carcinoma represents 3-4% of all head and neck malignant tumor. It typically occurs in the maxillary sinus antrum, nasal cavity, and ethmoid sinus. Two subtypes exist: 1) keratinizing and 2) non-keratinizing. A poorly-differentiated non-keratinizing SCC is depicted here. Many broad, interconnecting bands of neoplastic epithelium without keratinization characterizes this lesion (left). Pleomorphic cells with loss of polarity and marked mitotic activity are present (right).
Keratinizing SCC is much more common than non-keratinizing SCC, comprising 80-85% of all cases. It shows papillary, exophytic and inverted growth patterns with keratinization. Shown here is a moderately-differentiated sinonasal SCC (low mag: left; high mag: right).
Squamous cell carcinoma is the most common type of malignant neoplasm in the sinonasal cavity. It is typically seen in men older than 40 years. Etiology is unclear, but risk factors include nickel and thorotrast exposure. The lesion most commonly occurs in the antrum of maxillary sinus and nasal cavity. Less frequently, it can occur in the ethmoid, sphenoid, and frontal sinuses. Patients typically present with unilateral nasal obstruction, epistaxis, rhinorrhea or purulent nasal discharge. They can also present with non-healing ulcer or sore of the nasal cavity. Asymmetric facial deformity, paralysis and/or orbital involvement are common with larger lesions. The presenting symptoms of maxillary sinus SCC are similar to chronic sinusitis, and thus often lead to delayed diagnosis. The diagnosis should be followed by clinical staging. Treatment options include both surgical resection and radiation therapy.