DIFFUSE FIBROMATOSIS ON THE SCALP IN INFANCY - A VARIANT OF JUVENILE HYALINE FIBROMATOSIS

Various types of fibromatosis have been reported in infancy and early childhood. We describe an infant with diffuse fibromatosis on the scal p. A one year and five months-old girl showed a diffuse and hard mass 3 x 5 cm in diameter and no tenderness on the scalp. Two months later, the size of the mass had increased and several other tumors appeared on the lateral head. The magnetic resonance imaging (MRI) disclosed th at a large and diffuse tumor had spread from the frontal to occipital head; a 'helmet-like' configuration of the tumor was exhibited on sagi ttal MR images. The tumor showed high signal intensity on T2-weighted images and was enhanced with Gd-DTPA. Histological examination showed a fibroblastic proliferation with intervening thick collagen bundles. The patient was diagnosed as having diffuse fibromatosis. The tumor at the resection site immediately recurred, whereas the tumor in the fro ntal head showed marked regression. Three months after the resection, new tumors appeared in the occipital head. The size and number of thes e tumors have remained unchanged for more than 18 months. The sites an d appearance of the tumors were identical to that of juvenile hyaline fibromatosis (JHF) in this patient. However, JHF usually includes fibr oblasts associated with large amounts of hyalinized collagen-like mate rial, which were not present in our patient. The different histology o f JHF comparing our case and other reported cases may depend on the di fferent phase of the disease progression at resection. Long-term obser vation is necessary for the appropriate diagnosis and evaluation of pr ognosis in this patient.