Association of Familial Adenomatous Polyposis With Classic Papillary Thyroid Carcinoma and Acromegaly: A Case Report

Familial adenomatous polyposis (FAP) is caused by pathogenic variants in the APC gene and is typically associated with colorectal polyps and an increased risk of colorectal and other cancers.

This report presents a 40-year-old female patient with a history of FAP and classic papillary thyroid carcinoma who, during clinical evaluation and follow-up, developed signs and symptoms of acromegaly later confirmed by biochemical tests.

The relationship between acromegaly and colonic polyps, as well as with papillary thyroid carcinoma, depends primarily on insulin-like growth factor 1; the cribriform-morular subtype of thyroid carcinoma is linked to FAP through different molecular mechanisms, and its association with acromegaly had not been described, thereby opening the possibility of investigating the mechanisms underlying this connection.

This case illustrates a unique association among 3 uncommon pathologies that had not been previously reported.