Endocrine Abstracts

Introduction: Anaplastic thyroid cancer (ATC) is a highly aggressive endocrine tumor formed of undifferentiated follicular thyroid cells. ATC accounts for only 1-4% of all thyroid cancers. The therapeutic approach is typically multimodal, combining surgery, radiation and chemotherapy. However, ATC is often resistant to treatment. Hence, the reported median overall survival of ATC patients is ~3 months, with nearly 100% disease-specific mortality.

Case: A 65-year-old man presented to our outpatient endocrinology department with complaints of generalized weakness, sore throat, neck pain and fever. These symptoms lasted about four weeks. Upon examination, a solid ~3 cm nodule at the front of the neck was palpated. A full diagnostic work-up was performed.

Diagnostic tests: Laboratory tests: TSH 2.30 (0.4-3.6) mU/l, FT4 21.63 (7.87-20.3) pmol/l, FT3 4.29 (3.34-5.1) pmol/l, ATPO 3.00 (0-3.2) kIU/l, Anti-Tg 466.5 (0-13.6) kU/l, calcitonin 12.8 (normal range 0.56-2.81) pmol/l.

Thyroid ultrasound: A ~4.4x6.3 cm heterogeneous mass with calcifications in the right lobe of the thyroid gland and enlarged lymph nodes on the right side of the neck were detected.

Microscopic examination: A core needle biopsy (CNB) of the left thyroid lobe identified a stromal tumor, formed by atypical cells with large, polymorphic nuclei and background necrosis. An elevated mitotic rate and multinucleated giant cells resembling osteoclasts were also detected. Immunohistochemically, tumor cells were positive with PAX-8, vimentin, CK7 and focally positive with TTF-1 staining. Immunohistochemical staining with calcitonin and thyroglobulin - negative. CNB of an enlarged lymph node on the right side of the neck was not informative, with no apparent neoplastic changes.

Chest and neck CT: Imaging revealed a ~4.7×4.3×7.5 cm non-homogeneous nodular right thyroid lobe with calcifications. The mass descends retrosternally to the middle mediastinum, displacing the trachea and esophagus, infiltrating surrounding tissues. Paratracheal lymphadenopathy and an enlarged lymph node near the root of the right lung were visualized.

Treatment: A chemotherapy course with paclitaxel (135–175 mg/m²) and carboplatin (AUC 5–6) once every three weeks was initiated. The patient has undergone the third cycle of chemotherapy, reporting an overall sense of well-being and a notable reduction in discomfort in the cervical region. As for now, the regiment is continued. If chemotherapy proves effective, surgery will be scheduled.

Conclusion: ATC is a rare and highly aggressive type of thyroid cancer, characterized by uncontrolled and rapid growth. Thus, a prompt and comprehensive differential diagnosis and treatment plan are needed.