Skin abnormalities in individuals with macrocephaly: Cowden disease from a dermatologist's point of view.

Cowden disease is a rare autosomal dominant disorder characterized by multiple hamartomas and (malignant) tumors affecting major organs including the breast, thyroid, endometrium, brain, skin and mucosa. Diagnostic criteria as formulated by the International Cowden Consortium serve as a guideline to clinically identify patients in which Cowden disease is suspected. However, the spectrum of abnormalities associated with PTEN mutations is very broad, such that the term PTEN hamartoma tumor syndrome (PTHS) is often used. The diagnostic criteria for Cowden disease do not always serve to reliably identify patients who fall within the PTHS spectrum. Therefore, it is important that clinicians are aware of features that should raise the suspicion of such a syndrome. To illustrate this point, we present three patients with clinical features of the PTEN hamartoma tumor syndrome spectrum. These patients have macrocephaly in common. Two of them meet the criteria for Cowden disease; one patient refused mutation analysis, while mutation analysis in the other patient revealed no PTEN mutation. The third patient does not meet the criteria for Cowden disease; however, genetic analysis showed a pathogenic mutation in the PTEN gene. Dermatologists regularly encounter the (muco-)cutaneous abnormalities that can be seen in PTEN hamartoma tumor syndrome. These findings combined with a (family) history of internal malignancy or a macrocephaly should raise the suspicion of PTHS, even in the absence of classical Cowden criteria.