Cutaneous Manifestations of Juvenile Hyaline Fibromatosis

Abstract

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.