Endocrine Abstracts

Introduction: Anaplastic carcinoma of the thyroid (ATC) is the rarest and most aggressive thyroid gland cancer accounting for less than 5 % of all thyroid gland neoplasms. There is inconclusive evidence that ATC represents a terminal dedifferentiation of preexisting well-differentiated thyroid carcinoma or it may originate as already aggressive nondifferentiated cancer without any prior thyroid neoplasm.

Case description: Case 1: A 74-year-old woman with history of long-standing nodular goiter presented with rapidly growing, painful neck mass with compressive symptoms including hoarseness, dysphagia and vocal cord paralysis. She underwent debulking thyroid surgery in November 2021 revealing a right lobe 4/3/3 cm mass with histological features of anaplastic carcinoma and extensive infiltration of the surrounding soft tissues and muscles, esophagus, carotic artery, jugular vein, laryngeal nerve. Palliative radiotherapy was initiated together with adjuvant chemotherapy but the residual tumor showed progressive enlargement and lead to life-threatening complications.

Case 2: A 57-year-old man in whom on routine US examination in 2017 a solid hypoechoic nodule 3.6/3.3/4.5 cm with increased intranodular blood flow causing tracheal deviation and local compression was seen. The patient was referred to surgery which was not performed until April 2019 when he presented with significant enlargement of the thyroid mass. After total thyroidectomy the histological result was consistent with anaplastic carcinoma 9/8/7 cm in size with capsular and soft tissue infiltration. However, the patient refused any further treatment. On the last follow-up visit 32 months following the diagnosis the patient was euthyroid on replacement therapy with no clinically evident local recurrence or distant metastases.

Discussion and conclusion: Anaplastic thyroid carcinoma is poorly responsive to current treatment modalities with a 4-month median overall survival from the time of diagnosis. Recent study demonstrated significant improvement in survival over the last 2 decades presumably due the introduction of molecular-based personalized therapies. Among the most significant prognostic factors are considered age, size of the tumor, presence of extrathyroid invasion and distant metastases along with several new factors such as white blood cell and platelet count at presentation. The two stage IV B patients described presented with similar histological findings but completely different course of the disease. Further studies on the molecular characteristics of anaplastic cancers will probably provide valuable data on the individual risk of recurrence and progression and contribute to the improvement of the long-term prognosis.