The prevalence of goiter, thyroid nodules, and thyroid cancers in the pediatric population has increased. In some rare cases, local conditions such as juvenile desmoid-type fibromatosis (JDTF) can mimic specific thyroid pathology, complicating the diagnostic process. A 17-year-old obese adolescent girl was admitted to the Endocrinology Department with progressive swelling on the left side of the neck, persisting for approximately one year, recently accompanied by dysphonia and inspiratory dyspnea, and ultimately diagnosed as a unilateral nodular goiter associated with compressive phenomena. Despite her euthyroid status, the thyroid ultrasound identified a suspected, large, non-homogeneous, hypoechogenic nodule with calcifications in the left thyroid lobe (TI-RADS score of 4), confirmed by a cervical-region MRI. The biopsy specimens obtained through fine-needle aspiration were classified as Bethesda III ("atypia of undetermined significance" or "follicular lesion of undetermined significance"). Left thyroid lobe removal was performed by a specialized surgeon in thyroid pathology, with histopathological analysis revealing a diagnosis of JDTF in the thyroid gland. Post-surgery, the patient showed favorable progress without any relapse. Pediatric endocrinologists face challenges in diagnosing and managing thyroid nodules in children due to their higher malignancy potential. Familiarity with similar conditions, such as JDTF, is crucial in accurate diagnosis and appropriate pediatric management.