Pretibial subcutaneous soft tissue lesions presenting to a paediatric orthopaedic clinic.

Pretibial swellings in children usually represent erythema nodosum which exhibits characteristic skin changes. Three cases of pretibial subcutaneous lesions are presented which had no skin involvement or bony abnormalities on plain radiographs. At initial presentation, concerns of malignancy were raised but these lesions were ultimately diagnosed as granuloma annulare, fat necrosis and subcutaneous infection. In combination with clinical assessment and plain radiographs, MRI proved invaluable in reaching diagnosis and excluding neoplasia. Biopsy was only required in one case in this series after MRI. A tissue diagnosis, however, remains mandatory if there is any doubt over the nature of such lesions.