Work

Deceptive Thyroid Pathologies: Anaplastic Thyroid Carcinoma Mimics and Clinical Implications

Year: 2026

Type: article

Abstract: BACKGROUND: Beyond follicular-derived thyroid carcinomas, lymphomas, and metastatic disease, there are rare pathologies of the thyroid gland that represent a challenge. We report patients with unusual malignancies that mimic similar aggressive cancers. METHODS: Retrospective case series. RESULTS: Eight patients with aggressive thyroid tumors presented with clinical and radiographic features concerning for anaplastic thyroid cancer (ATC). Three patients presumed to be diagnosed with Adamantinoma-like Ewing sarcoma (ALES), each harboring an EWSR1-FLI1 rearrangement. One patient with an enlarging neck mass was found to have osteoid-producing osteosarcoma. Another patient with a bulky neck mass and metastases demonstrated neolumen and ERG/CD31 positivity, confirming thyroid angiosarcoma. A separate patient was diagnosed with a high-grade sarcoma harboring a PRMT8-NTRK fusion, representing the first reported case. Two patients had mucoepidermoid carcinoma (MEC) variants-one classic MEC and one sclerosing MEC with eosinophilia (SMECE). CONCLUSIONS: Multiple rare thyroid malignancies may present indistinguishably from ATC, emphasizing the need for meticulous histopathologic and molecular evaluation.

Source: Head & Neck

DOI: 10.1002/hed.70201