Granular cell myoblastoma of the tongue in a 2-year-old girl: a case report.

Granular cell tumours are uncommon lesions, although the head and neck region accounts for approximately 50% of all lesions. It is not clear whether or not granular cell tumour is a true neoplasm, a developmental anomaly, or a trauma-induced proliferation. The basic cell of origin is now thought to be neural, although past reports frequently indicated an origin from striated muscle, or less frequently an origin from histiocytes, fibroblasts or pericytes. The tongue and the buccal mucosa are common intraoral sites. The other head and neck site likely to be involved is the larynx. The tumour generally occurs in middle or older aged adults. More than a third of all granular cell tumours occur on the lingual dorsum, usually as a sessile, painless, somewhat firm, immoveable nodule less than 1.5 cm in greatest diameter. Lesions often demonstrate a pallor or a yellowish discolouration and typically have a smooth surface. Histochemical and ultrastructural studies propose the origin of the lesion from Schwann cells, striated muscle, mesenchymal cells, histiocytes and epithelial cells. As most of the granular cell tumours are benign, surgical excision of the lesion is the treatment of choice.