Cribriform-morular variant of papillary thyroid carcinoma in an 8-year-old girl: a case report with immunohistochemical and molecular testing.

The description of the histological features and the immunohistochemical and molecular analyses of a case of cribriform-morular variant of papillary thyroid carcinoma in an 8-year-old girl with a family history of adenomatous polyposis is presented. The neoplasm was multifocal and bilateral, with a mixed pattern of solid, trabecular, and morular areas. The neoplasm showed angioinvasive behavior, extracapsular infiltration with extension to the perythyroidal muscles, and lymph node metastases. Tumor cells were positive for CAM 5.2, cytokeratins 5/6, TTF-1, HBME-1, galectin-3, and β-catenin. In addition, the molecular tests did not reveal BRAF mutations, RET/PTC rearrangement, APC mutation, or KRAS mutation.