Leiomyomatous hamartoma of the tongue in an infant: a case report.

A case of leiomyomatous hamartoma in the postmedian region of the dorsum of the tongue in a 3-year-old boy is reported. This lesion had been noticed at about 1 year of age but was left untreated. The intensity of the inner region of the mass was homogenous and similar to that of the surrounding tongue muscle on both T1- and T2-weighted images of an MRI. The mass was diagnosed as benign tumor of the tongue and resected. Histopathologically, nodular overgrowth of spindle cells containing eosinophilic cytoplasm was noted in the submucoepithelial connective tissue. In immunohistochemical staining, spindle cells were negative for S-100 protein and positive for vimentin and -SMA, suggesting that these cells were derived from smooth muscle. In the 10 months after surgery, there has been no recurrence of the lesion. To our knowledge, only 26 cases (including the present case) have been diagnosed histopathologically as leiomyomatous hamartoma in the oral cavity between 1945 and 2009. Clinical features, differential diagnosis, and treatment are discussed herein.