Hibernomas of the head and neck.

Hibernomas are rare tumors derived from brown adipose tissue, a specialized form of fat tissue found in hibernating and nonhibernating animals. Only a minority of reported hibernomas have occurred in the head and neck region. This report describes two cases of cervical hibernomas, one of which was preoperatively diagnosed by the use of fine-needle aspiration biopsy. The clinical and pathologic characteristics of this neoplasm are reviewed. In general, hibernomas are slow-growing tumors with inconclusive evidence for the existence of a malignant variant. A review of the literature supports the conclusion that excision, sparing vital structures, appears to be curative.