Pilomatricoma-like changes in the epidermal cysts of Gardner's syndrome.

We studied fifty-seven cutaneous cysts from seven members of a kindred with Gardner's syndrome. All of the cysts had large areas indistinguishable from ordinary epidermal cysts. In addition, twenty-one (37%) contained columns of shadow cells, similar to those of pilomatricoma, that projected into the lumina. The cells at the point of attachment of the columns to the cyst lining were often indistinguishable from the hair matrix-like, basophilic cells of pilomatricoma. In twenty-nine cysts (51%), masses of shadow cells were free within lumina, unattached to the epithelial lining. Deposits of shadow cells, associated with a giant cell reaction and often calcified, were present in the pericystic connective tissue of twenty cysts (35%). Thirty-six of the fifty-seven cysts (63%) had one or more of the foregoing features, and the changes were observed in cysts from six of the seven patients studied. Our observations and similar findings recorded in the literature suggest that pilomatricoma-like changes may be a characteristic of the epidermal cysts of an undetermined number of kindreds with Gardner's syndrome.