Management and Follow-up of Sporadic Cribriform-Morular Thyroid Carcinoma After the 2022 World Health Organization Reclassification

Objective Cribriform-morular thyroid carcinoma (CMTC) has been reclassified as a distinct thyroid tumor entity in the 2022 World Health Organization classification, no longer considered a subtype of papillary thyroid carcinoma. This redefinition raises important questions regarding postoperative management, including the need for radioactive iodine (RAI), thyroid-stimulating hormone (TSH) suppression, thyroglobulin monitoring, and screening for familial adenomatous polyposis (FAP). We report an apparently sporadic case and discuss a risk-adapted management approach. Case Report A 24-year-old woman presented with a progressively enlarging right-sided neck mass. Thyroid ultrasound revealed a 2.8 cm predominantly solid, hypoechoic nodule (ACR TI-RADS 4), and fine-needle aspiration cytology was classified as Bethesda category V. Total thyroidectomy was performed. Histopathology confirmed CMTC with cribriform and morular architecture and focal vascular invasion, without extrathyroidal extension or nodal involvement (pT2 N 0). Immunohistochemistry demonstrated nuclear β-catenin expression and absence of thyroglobulin staining. There was no personal or family history of thyroid disease or polyposis. Colonoscopy was normal, and germline whole-exome sequencing did not identify pathogenic variants in adenomatous polyposis coli or other cancer-predisposition genes. Given the absence of high-risk features and no evidence of FAP, RAI therapy and TSH suppression were not administered. The patient remains disease-free after 24 months, under surveillance with periodic cervical ultrasonography. Discussion CMTC management should not automatically follow conventional papillary thyroid carcinoma paradigms. In apparently sporadic, low-risk cases, a conservative postoperative strategy may be appropriate. Conclusion This case supports an individualized, risk-adapted approach to CMTC, in which omission of RAI and aggressive TSH suppression may be reasonable without compromising oncologic safety.