Primary ameloblastoma of the sinonasal tract: a clinicopathologic study of 24 cases.

BACKGROUND: Ameloblastomas are locally aggressive jaw tumors with a high propensity for recurrence and are believed to arise from the remnants of odontogenic epithelium. Extragnathic ameloblastomas are unusual and primary sinonasal tract origin is extraordinarily uncommon.
METHODS: Twenty-four cases of ameloblastoma confined to the sinonasal tract were retrieved from the Otorhinolaryngic-Head & Neck Pathology and Oral-Maxillofacial Pathology Tumor Registries of the Armed Forces Institute of Pathology between 1956 and 1996.
RESULTS: The patients included 5 females and 19 males with an age range of 43-81 years, with a mean age at presentation of 59.7 years. The patients presented with an enlarging mass in the maxillary sinus or nasal cavity (n = 24), sinusitis (n = 9), or epistaxis (n = 8). Unilateral opacification of the maxillary sinus (n = 12) was the most common radiographic finding. Histologically, the tumors exhibited the characteristic features of ameloblastoma, including peripherally palisaded columnar cells with reverse polarity. The majority of the tumors showed a plexiform growth pattern. Fifteen tumors demonstrated surface epithelial derivation. Surgical excision is the treatment of choice, ranging from conservative surgery (polypectomy) to more aggressive surgery (radical maxillectomy). Five patients experienced at least 1 recurrence, usually within 1 year of initial surgery. With follow-up intervals of up to 44 years (mean, 9.5 years), all 24 patients were alive without evidence of disease or had died of unrelated causes, without evidence of disease.
CONCLUSIONS: Primary ameloblastoma of the sinonasal tract is rare. In contrast to their gnathic counterparts, sinonasal tract tumors have a predilection for older age men. Therapy should be directed toward complete surgical resection to prevent local tumor recurrence.