Alveolar soft part sarcoma of the head and neck region.

Alveolar soft part sarcoma is a soft tissue malignancy most often found in the extremities of young adults; when these tumors arise in the head and neck area, they usually appear in the orbit or the tongue. Their initial behavior is relatively indolent, but over time a sizable number of these tumors recur locally and metastasize; as such, they are best regarded as fully malignant neoplasms. The derivation of these tumors remains uncertain: while some have suggested that these are tumors of muscle origin and others have postulated a neuroendocrine origin, the evidence accumulated to date is conflicting, and so these neoplasms continue to be regarded as tumors of uncertain origin. Surgical excision is the mainstay of therapy.