We report a healthy baby boy, born after an uneventful pregnancy at 40 weeks gestation, birth weight 3420 g, Apgar 9–10–10. On examination the baby had a lingual mass anteriorly situated in the midline, 5×5×5 mm. It was not painful but it had a hard consistency. There were no respiratory or feeding problems. However, screening for congenital hypothyroidism was positive.

He was treated with levothyroxine. Further investigation using technetium 99m scanning and ultrasound suggested dystrophic cervical thyroid tissue. Histopathological and immunohistochemical studies showed no thyroid tissue in the tumour. This was to be expected owing to the fact that ectopic thyroid tissue on the tongue is almost always found posteriorly. Further histological evaluation showed striated vascular tissue and smooth muscle fibres. Leiomyomateus hamartoma was diagnosed (fig 1).

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Figure 1 Baby with hamartoma of the tongue. Parental consent was obtained to publish this figure.

Hamartomas are malformations of histologically normal cells in an abnormal structure. Hamartomas of the tongue in neonates are extremely rare, mostly located posterior to the midline and often of vascular origin. As a rule, recurrences after resection are rarely seen.