Case Report: Giant Thyroid Angiolipoma-Challenging Clinical Diagnosis and Novel Genetic Alterations.

Background: A 64-year-old man presented with a 7.8 cm lipomatous thyroid mass discovered on magnetic resonance imaging.

Methods: After two non-diagnostic fine needle aspirations (FNAs) were performed, computed tomography (CT) revealed features concerning for malignancy including central necrosis and infiltrative borders. A third FNA was still non-diagnostic. Total thyroidectomy was performed.

Results: Upon pathologic examination, the final diagnosis was primary thyroid angiolipoma. The lesion contained central fat necrosis with ischemic features, attributable to the FNAs.

Conclusion: Ours is the third published case report of this rare entity. To date, no lipomatous thyroid tumor has undergone extensive genomic testing. Next-generation sequencing of our case revealed multiple genetic alterations, supporting the concept of angiolipomas being true neoplasms. Whereas the two previously reported cases in the literature were radiographically much smaller and appeared indolent, the large tumor in our case exhibited radiographic features concerning for liposarcoma, which belied the benign final pathologic diagnosis. Our case demonstrates that conservative surgical management (partial thyroidectomy) may be considered for lipomatous thyroid tumors, with further interventions to be determined only after final pathologic diagnosis.