The Cowden syndrome: a clinical and genetic study in 21 patients

Abstract

An analysis of the findings in 21 patients with the Cowden syndrome or the multiple hamartoma syndrome is presented. The Cowden syndrome is a cancer‐associated genodermatosis with characteristic mucocutaneous findings and a wide array of associated abnormalities including a high incidence of breast cancer in female patients. Genetic studies confirmed autosomal dominant inheritance with a high penetrance in both sexes and moderate interfamilial and intrafamilial differences in the expressivity of a number of symptoms. Familial occurrence was present in 4 of the 7 families. There was a strong predominance of female patients (6:1), which may be fortuitous. Mucocutaneous changes were the most constant (100% incidence) and characteristic findings; they almost invariably became manifest in the second decade. Four of our 18 female patients (22%) were treated for breast cancer, a lower incidence than reported previously. No increased incidence of other types of malignancies was found. Craniomegaly (high head circumference) was found to be the most common extracutaneous manifestation (80% incidence); craniomegaly appears to be an important early marker. We also found high incidences of gastrointestinal polyps (approximately 60%) and cutaneous fibromas (76%), while the incidence of thyroid abnormalities, thus far regarded as the most common extracutaneous finding, was similar to that reported previously (62%). G‐banded karyotype and preliminary DNA‐repair studies revealed no clear abnormalities. No linkage with the loci of HLA, and immunoglobulin haplotypes was found.