Which of the following is a sign of Cowden's disease?

Cowden's disease, also known as PTEN hamartoma tumor syndrome, is a genetic condition characterized by an increased risk of certain types of tumors and a variety of benign growths. One of the hallmark signs of Cowden's disease is acral keratosis, which refers to the development of keratosis or thickening of the skin on the palms of the hands, soles of the feet, and other acral areas. This feature can be particularly helpful in clinical recognition of the disease, alongside other manifestations such as hamartomas and a predisposition to malignancies.

The occurrence of acral keratosis in individuals with Cowden's disease is specifically associated with the genetic mutations affecting the PTEN gene, which has a critical role in regulating cell growth and preventing tumor formation. Thus, the presence of acral keratosis serves as an important diagnostic clue when evaluating a patient for Cowden's disease.

The other conditions listed—including thyroid carcinoma, liver tumors, and pancreatic cysts—are related to different syndromes or carry different implications in other conditions but are not as characteristic of Cowden's disease as acral keratosis. While individuals with Cowden's disease can have an increased risk of thyroid cancer, it is not