FAP associated cribriform morular variant of PTC: striking female prevalence and indolent course.

A papillary thyroid carcinoma (PTC) is reported in 18 patients with FAP, all females. The diagnosis was concomitant in 1/3, whereas in 1/3 FAP preceded and 1/3 was subsequent. A cribiform morular variant (CMV) of PTC was present in 2 patients. The germline APC mutation was detected in 16 out of 18: 5’ to codon 1220 in 14 and in codon 1309 in 2. Even if CMV-PTC is associated with FAP in more than 50% of cases, not all FAP associated PTC show this variant. FAP associated PTC occurs quite exclusively in females and has a good prognosis. On the contrary, sporadic CMV-PTC often occurs in males and tends to have an aggressive behavior. Therefore, caution is suggested before stating that, despite similar features, these tumors should be regarded as a single entity.