Endocrine Abstracts

Introduction: Poorly differentiated carcinoma (PDTC) is an aggressive and rare form of thyroid carcinoma that originates from follicular cells and accounts for only 1-3 percent of all thyroid carcinomas diagnosed¹. Most of the limited instances of PDTCs have been observed in older individuals. Instances in the pediatric population are exceedingly rare².

Case report: This report refers 17-year-old female, who presented moderate hirsutism (scoring 8 points on the Ferriman-Gallwey scale), normal puberty development (Tanner stage B3P4), and regular periods. Upon physical examination, the patient exhibited an enlarged thyroid (IB degree), Laboratory examination showed normal levels of sex hormones, elevated antibodies against thyroid peroxidase and thyroglobulin, and thyroid-stimulating hormone concentration. Thyroid ultrasound revealed a right thyroid hypoechoic heterogeneous structure nodule, with microcalcifications and groups of them, measuring up to 2.7×2.8×4.1 cm in size. A fine-needle aspiration biopsy and cytological examination of the mass found undetermined significance atypia (Bethesda category III). Due to the abundant presence of lymphocytes, lymphocytic thyroiditis was suspected. In consideration of a potential tumor process, it was decided to carry out a complete thyroidectomy. Histopathology determined high-grade PDTC of the right thyroid lobe. The patient underwent radioactive iodine therapy following the completion of thyroidectomy. The treatment was well tolerated, with no observed side effects noted. Following the completion of the treatment, a PET/CT scan with fluorodeoxyglucose (FDG) was performed, during which no focal pathological FDG accumulation was detected. There were not detected pathological variants in PTEN, PRKAR1A, APC, TP53, RET, DICER1 genes.

Conclusions: This case emphasizes the challenges in diagnosing and treating thyroid disorders in young patients. The successful management PDTC through thyroidectomy and radioactive iodine therapy is notable. The absence of FDG accumulation post-treatment indicates a positive therapeutic response. This underscores the significance of comprehensive assessment and collaborative care for rare thyroid conditions in adolescents.

Keywords: adolescent, poorly differentiated thyroid carcinoma, thyroidectomy, radioactive Iodine therapy

References: 1. Xu B, Ghossein R. Poorly differentiated thyroid carcinoma. 2020; Available from: https://doi.org/10.1053/j.semdp.2020.03.003 2. Choi SW, Lee J-H, Kim YY, Chung YS, Choi S, Kim NR, et al. Poorly differentiated thyroid carcinoma: An institutional experience. Korean J Clin Oncol. 2020 Jun 30;16(1):25. Available from: /pmc/articles/PMC9942713/