Schwannoma of the Nasal Ala in a 13 Year-Old Boy

A 13 year-old boy presented to the Ear Nose Throat clinic with a 6-month history of nasal obstruction due to a progressively enlarging, nonpainful growth within the right anterior nasal vestibule. Examination revealed a 1.3-cm submucosal mass on the ventral surface of the right lower lateral crural cartilage (LLC). The mass encompassed the area just cephalic to the intercartilaginous junction and spanned the under surface of the LLC caudally to the alar margin (Figure 1).

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Figure 1.

Right lower lateral cartilage schwannoma extending to alar margin (arrow).

A benign cyst was initially considered, so imaging was not performed and the patient was scheduled for surgical resection. A transcartilaginous incision was made overlying the mass which was easily dissected from the surrounding tissues and alar cartilage perichondrium.

Histopathologic sections of the 1.3 cm × 1.0 cm right intranasal tumor revealed an encapsulated mass composed predominantly of compact cellular areas of elongated spindle cells with wavy nuclei arranged in fascicles and alternating parallel arrays or palisades around fibrillar processes consistent with Verocay bodies (Figure 2). Ectatic small vessels are scattered throughout and rare vessels show perivascular hyalinization. The findings are consistent with a conventional (common or solitary) schwannoma.

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Figure 2.

Histopathologic section of alar schwannoma with classic Verocay bodies (arrows).

Schwannomas are benign encapsulated peripheral nerve sheath tumors composed of neoplastic Schwann cells. These tumors may show varying amounts of 2 architectural patterns designated Antoni A and B. Antoni A contains more cellular areas showing compact, elongated, fusiform cells with spindled nuclei, moderate amounts of eosinophilic cytoplasm, indistinct cellular borders, and little to no nuclear pleomorphism. Scattered pleomorphic or bizarre nuclei may be observed in some cases with no prognostic implications. Verocay bodies, which are a classic feature, show nuclear palisading around fibrillar processes. Antoni B contains hypocellular areas of loosely textured cells with indistinct cellular processes, variable lipidization, and myxoid stroma and hyalinized vessels.

Schwannomas are observed in the head and neck region approximately 45% of the time with sinonasal schwannomas comprising only 4% of these cases. ¹ Schwannomas of the nasal alar cartilages are exceedingly rare with only 4 previous cases being described. Even more rare are nasal alar schwannomas in children, and this is the only known case of a conventional schwannoma of the nasal ala in a pediatric patient.

The origin of schwannomas involving the nasal tip area is unclear, although it has been postulated that terminal somatosensory branches of the trigeminal nerve are involved. ^2,3

Along with the conventional tumor type, other forms of schwannoma have been described and include plexiform, cellular, ancient forms and melanocytic schwannoma. ^4,5,6

Conventional schwannomas, such as the case being discussed very rarely become malignant and are usually amenable to complete surgical removal. This is in contrast to plexiform schwannomas that while also benign are diffusely located, devoid of a capsule and prone to local recurrence, especially if excised with inadequate margins. ⁷