Familial cutaneous collagenoma: genetic studies on a family.

Familial cutaneous collagenoma is an inherited condition characterized by the presence of multiple dermal nodules symmetrically distributed on the trunk and upper arms. In this study, six patients, the proband, his four siblings and a niece, representing a kindred of fifty-two subjects, were examined for aymptomatic cutaneous nodules mainly on the back and chest. The individual lesions varying from a few millimetres to several centimetres in size, were indurated, and showed minimal epidermal changes. Histologically, the nodules were characterized by an excessive accumulation of dense, coarse collagen fibres in the dermis. The elastic fibres appeared diminished in number, and in some areas they were abnormally thin and fragmented. The lesions, therefore, were connective tissue naevi of the collagen type. On the basis of the family history and histological observations the patients were diagnosed as having familial cutaneous collagenoma. Examination of the family pedigree indicated that the dermal nodules in familial cutaneous collagenoma were inherited in an autosomal dominant pattern. It was also observed that the lesions had an onset at the age of 15 to 19 years, and their number increased significantly during pregnancy. It is conceivable that familial cutaneous collagenoma is an inherited condition whose expression may be under a hormonal control.