An Exceptionally Indolent Course of Papillary Thyroid Carcinoma: A 37-Year Untreated Case with Extensive Local Progression and No Anaplastic Transformation

Papillary thyroid carcinoma (PTC) typically has an indolent course and an excellent prognosis.However, in long-standing untreated cases, PTC may occasionally undergo anaplastic transformation.We report the case of a 63-year-old woman with a PTC diagnosed in 1986 that remained untreated for 37 years.In September 2023, after years without medical or surgical intervention, she presented with a large cervical mass and multiple bleeding skin ulcers.Imaging showed a heterogeneous 9.2 8.7 11.2 cm thyroid mass infiltrating surrounding structures.Fine-needle aspiration confirmed PTC (Bethesda VI), and the patient underwent a complex total thyroidectomy with partial skin resection.Histology revealed well-differentiated PTC with skeletal muscle infiltration but no anaplastic features.Adjuvant radioiodine therapy was recommended.This case demonstrates an extraordinary example of a long-standing untreated PTC that did not undergo anaplastic transformation despite extensive local progression.It emphasizes the importance of regular follow-up and the potential risks of neglecting thyroid malignancies.