Endocrine Abstracts

JOINT1997

Introduction: Oncocytic carcinoma is a rare form of thyroid cancer that develops from oncocytic cells, a specialized form of follicular thyroid cells. Representing only 4% of thyroid cancers, it is known for its more aggressive nature, with high potential for lymphatic and distant metastasis, requiring early treatment with regular monitoring to improve prognosis. Its detection as a hot nodule is exceptional, as it is most often considered a benign lesion.

Case report: We report the case of a 69 years old female patient with a medical history of type 2 diabetes treated with metformin, sulfonylurea, and basal insulin, hypertension treated with Ramipril, and dyslipidemia treated with simvastatin, followed for a multinodular goiter. The cervical ultrasound revealed an enlarged thyroid gland (58 ml) with several nodules, the most concerning being in the right upper pole, measuring 10x17 mm, classified as EUTIRADS IV. The biological assessment showed a low-normal TSH, and the additional thyroid scintigraphy with Tc99m revealed a large goiter predominantly on the left, with two hot nodules, one of which was a medium-sized apical nodule on the right. The patient underwent a total thyroidectomy, and the histopathological examination revealed the presence of an oncocytic carcinoma in the right lobe of the thyroid, with vascular emboli, classified as PT2NxMx. A follow-up high-dose radioactive iodine therapy was advised. The patient is currently receiving suppressive hormone therapy with levothyroxine.

Discussion and Conclusion: Thyroid cancers most often present as a cold nodule, and only 3% of cases present as a hot nodule. Fine needle aspiration of the latter is not recommended due to its low malignancy rate. However, it is crucial not to rule out the possibility of thyroid cancer and to inform the patient about the risk of its occurrence. The oncocytic form found in our patient remains even rarer, with few cases reported in the literature. Curative treatment involves total thyroidectomy which decreases the risk of recurrence and allows for postoperative monitoring of thyroglobulin levels, an essential marker for recurrence of oncocytic carcinoma. Additionally, if lymph nodes are clinically positive, a therapeutic neck dissection of the central and lateral compartments is indicated. In contrast to other types of thyroid cancer, oncocytic carcinoma has a reduced capacity for radioactive iodine uptake, making it less suitable for this treatment. However, newer therapies, including tyrosine kinase inhibitors, may be considered.