Infantile systemic hyalinosis or juvenile hyaline fibromatosis?

Infantile systemic hyalinosis and juvenile hyaline fibromatosis are presumably autosomal recessive inherited diseases of unknown origin in which accumulation of an amorphous, hyaline material occurs in the skin and other organs. Both disorders may show clinical overlapping, suggesting that they might represent different variants of the same disease spectrum. We describe a 6-year-old boy with such overlap. Salient features included papular skin lesions on his face and neck, gingival hyperplasia, perianal nodules, large subcutaneous tumors on the scalp, hyperpigmented plaques over the metacarpophalangeal joints and malleoli, limited joint movement, diffuse osteopenia, short stature, and persistent diarrhea. Histopathologic and ultrastructural studies confirmed the presence of hyalin material in the dermis. The term systemic hyalinosis involves both conditions and should be preferred until a clear distinction can be made between them.