Ultrasound Features of Adolescent Cribriform-Morular Variant Papillary Thyroid Carcinoma and Its Association With APC Gene Syndrome: A Case Report.

We report the case of a 16-year-old female with cribriform-morular variant of papillary thyroid carcinoma (CMV-PTC) and a confirmed germline APC mutation, with a history of childhood medulloblastoma consistent with Turcot syndrome Type 2. Ultrasound revealed bilateral, multifocal, predominantly hypoechoic nodules with mixed cystic-solid components and well-defined margins, without microcalcifications. The nodules grew rapidly over 2 years of surveillance, prompting total thyroidectomy. Histopathology confirmed bilateral CMV-PTC with capsular invasion. At age 19, the patient developed cervical lymph node and pulmonary metastases. Previous reports have described CMTC/CMV-PTC as presenting with bilateral or multifocal hypoechoic nodules, relatively well-defined margins, and infrequent microcalcifications. Recognition of these features in a young patient should raise consideration of an underlying APC-related syndrome and prompt genetic evaluation, even in the absence of a family history.