Abstract

Juvenile hyaline fibromatosis is a rare disorder probably inherited as an autosomal recessive trait. It is characterized by multiple slowly growing subcutaneous nodules, hypertrophy of gingiva, flexion contracture, and radiolucent bone destruction. The histological features of the tumor-like lesions are characterized by the deposition of amorphous hyaline material in which spindle shaped cells are embedded. We report a case of juvenile hyaline fibromatosis in a 26 year-old-woman. She had multiple subcutaneous nodules in scalp, ear, forearms, right knee, and back. Surgical excision of the tumors in the scalp and ear was done. The largest one measured 13 9 6 cm, and had homogeneous, grayish yellow cut surface with calcification. Light microscopic examination showed abundant eosinophilic hyaline material with extensive calcification and metaplastic bone formation. Spindle cells were rarely observed at the periphery of the tumor. Hyaline matrix was PAS positive, diastase resistant, and alcian blue negative. Scattered spindle cells were positive for vimentin but negative for S-100 protein and smooth muscle actin. There were many reports regarding early lesions of juvenile hyaline fibromatosis; however in this patient, tumor existed for more than 20 years and the histology was somewhat different from the early lesions reported in the literature.

• Keywords: Juvenile hyaline fibromatosis;Adult;Scalp;Ear;