Circumscribed storiform collagenoma (sclerosing fibroma).

In the past several years we have examined eight dermal nodules that have morphologic features identical to the nodules described in patients with Cowden's disease. The patients in this series had no other clinical manifestations of Cowden's disease. In an attempt to better define this distinctive entity, we subjected tissue sections to a battery of histochemical and immunohistochemical stains and examined tissue from one of the nodules ultrastructurally. Although we found similarities between these nodules and other common dermal fibrotic lesions, we believe that they are distinctive architecturally (they are sharply circumscribed and have a strikingly uniform storiform pattern) and immunohistochemically (with uniformly scattered factor 13a-positive cells). Because of the unique histologic features, we propose that the term "circumscribed storiform collagenoma" be applied to these nodules.