Abstract
A healthy girl of 10 years presented with lumps on her tongue, shown on biopsy to be neuromas. She had had operations to her feet for pes cavus and was relatively long-limbed but had no other 'Marfanoid' features. She had a high plasma calcitonin level. At operation a normal sized thyroid gland was totally removed. It contained two discrete masses of malignant C-cells and diffuse foci elsewhere. The plasma calcitonin fell slowly to normal on follow-up but was noted to be rising 2 1/2 years later. We stress the importance of making this diagnosis as early as possible and mention briefly another child aged 15 months, similarly diagnosed and operated upon.