Subperiosteal bone proliferation at the tibia in neurofibromatosis — a case report

Abstract

A very rare case of subperiosteal bone proliferation described as ‘a bone cyst’ on the distal end of the tibia in association with neurofibromatosis is reported in a 9-year-old girl. The pathological finding progressed within 6 months from ‘a cyst-like bone lesion’ filled with haematoma to ‘a bony protuberance’ and is documented with plain X-rays, CT and MRI, and subperiosteal haemorrhage on the tibia was strongly suspected. Clinical findings met the NIH criteria for neurofibromatosis, and the histopathological features were consistent with neurofibromatosis. To our knowledge, only 21 cases of this lesion have been reported in the literature. The cause of this lesion is the subperiosteal haemorrhage caused by periosteal abnormalities due to inversion by neurofibromatosis or mesodermal dysplasia. In spite of their frequent recurrences these lesions become huge and cause deformity and they should be resected before functional and cosmetic problems occur.