Cutaneous Manifestations of Juvenile Hyaline Fibromatosis

An 11-year-old adopted male presented with deforming scalp and bilateral posterior auricular nodules, joint contractures, and gingival hypertrophy. Histopathologic examination of the skin nodules revealed a normal epidermis with areas of extracellular eosinophilic ground substance surrounding benign spindle-shaped (myo)fibroblasts in the dermis and subcutis, alternating with hyalinized, acellular zones. The spindle cells did not show cytologic atypia. A diagnosis of juvenile hyaline fibromatosis (JHF) was given. The patient had been seen multiple times in the past for similar recurring, disfiguring dermal and subcutaneous nodules. The patient had a history of osteolytic lesions of the distal radius and ulna and hyaline deposition involving the sigmoid colon and rectum. JHF is a rare autosomal recessive hyalinosis with mutations of the Capillary Morphogenesis Gene-2 (CMG-2) at chromosome 4q21, a region that encodes a binding protein that concatenates capillary collagen IV to laminin. Other genetic abnormalities include mutations in dermal collagen (types I and III). Disease onset occurs early in life. Organ involvement is an ominous sign usually resulting in death during infancy or early childhood. Surgery is the only presently available treatment.