Oncocytic carcinoma of the thyroid: Conclusions from a 20-year patient cohort.

BACKGROUND: Oncocytic carcinoma (OCA) was recently reclassified as a distinct differentiated thyroid carcinoma (DTC). Given its rarity, OCA studies are limited. This study describes the characteristics of OCA in a 20-year cohort. METHODS: Retrospective analysis of patients with OCA at a single tertiary care hospital from 2000 to 2021. RESULTS: Fifty-one OCA patients (22M:29F) were identified. The mean age at diagnosis was 60.3 years; 90% presented as palpable mass; 24% had a family history of thyroid cancer. None had vocal fold paresis. On ultrasound, most tumors were solid and hypoechoic. FNA (n = 14) showed Bethesda-4 lesions in 93%. All were treated surgically. Histologically, 63% demonstrated angioinvasion, 35% had lymphovascular invasion, and 15% had extrathyroidal extension. Radioactive iodine was used as adjunct therapy in 77%. CONCLUSION: OCA has distinct features that distinguish it from other DTCs, and additional focused studies will help clarify the aggressive nature, treatment options, and prognosis of the disease.

Thyroid cancer necrosis not evident on imaging: A cautionary case series on poorly differentiated thyroid carcinoma diagnosed only on final pathology.

OBJECTIVE: Poorly-differentiated thyroid cancer (PDTC) is a highly aggressive malignancy which is recently defined and understudied in the radiologic literature. Necrosis is a key histopathologic criterion for the diagnosis of PDTC. We illustrate the current difficulty in accurate identification of histopathologic necrosis on preoperative imaging. METHODS: A series of seven patients with the final diagnosis of PDTC from our institution were identified. Multimodality preoperative imaging was analyzed by two head and neck radiologists. Final pathology reports were queried confirming histopathologic evidence of necrosis. RESULTS: Patients presented with a wide range of preoperative imaging features. A consistent imaging appearance confirming necrosis was not identified. All patients were subsequently upstaged to PDTC following final pathological analysis. CONCLUSION: A lack of definitive evidence of necrosis on preoperative imaging does not exclude the possibility of PDTC. We demonstrate the need for further research to establish a clear methodology for the preoperative diagnosis of PDTC.