Familial cutaneous collagenoma: a clinicopathologic study of two new cases.

Two siblings with familial cutaneous collagenoma syndrome had the essential clinical features of multiple skin-colored nodules on the trunk and upper arms. On light microscopy, histopathologic findings included excessive accumulation of dense, coarse collagen in the dermis. Elastic tissue stains demonstrated a proportionately diminished number of abnormal elastic fibers intermingled with the collagen bundles. A predominance of densely packed collagen bundles of normal morphology with a marked decrease in abnormal elastic tissue were the major ultrastructural features. The diagnosis was therefore confirmed to be connective tissue nevi of the collagen type. The differential diagnosis of connective tissue nevi disorders is delineated.