Leiomyomatous hamartoma of the midline maxillary gingival presenting as a congenital epulis: a case report with an immunohistochemical study.

An otherwise-healthy 2-year-old Japanese female presented with a polyp-like lesion on the palatal surface at the incisive papilla. The appearance of the lesion was similar to that of a congenital epulis. The histological findings showed proliferating mesenchymal components that contained mainly smooth muscle admixed with collagen fibres, nerve fibres, small vessels and mucous salivary glands. The immunohistochemical staining findings for α-smooth-muscle actin, desmin and S-100 protein were all positive. The histological diagnosis was therefore leiomyomatous hamartoma, based on clinical microscopic observations.