De-differentiation of papillary thyroid carcinoma into squamous cell carcinoma in an elderly patient: A case report.

Yotsapon Thewjitcharoen, Sirinate Krittiyawong, Siriwan Butadej, Soontaree Nakasatien, Somsong Polchart, Pairoj Junyangdikul, Auchai Kanchanapituk, Thep Himathongkam

Medicine 2020 Apr

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The unpredictability of thyroid cancer can be striking, as the disease may rapidly progress to death in some individuals. Herein, we reported a rare case of aggressive papillary thyroid cell carcinoma (PTC) in an elderly patient de-differentiated into squamous cell carcinoma (SCC). We describe a case of a 79-year-old Thai woman presented with hoarseness and neck mass for 2 months and she had been diagnosed with a 3-cm papillary thyroid carcinoma (PTC) in the right side of the thyroid gland. Later on PTC de-differentiated into SCC within 3 years after initial presentation. De-differentiation from papillary thyroid carcinoma to squamous cell carcinoma. The patient underwent a total thyroidectomy at the initial hospital and received high dose radioactive iodine (RAI) treatment at our hospital 1 month following the surgery and then was lost to follow-up. Two years later she came back with new development of right solid-cystic neck mass which was found to be recurrent PTC. A radical neck dissection was done and another high dose RAI treatment was given. However, she developed recurrent mass with tenderness at the site above previous solid cystic mass 6 months later. Re-exploration of the neck mass revealed an inflamed midline mass 2 cm with enlarged right lateral cervical lymph nodes. A histopathological examination of the midline neck mass showed poorly differentiated SCC with lymphatic invasion. The intermingling of two morphologically distinct tumors, a typical PTC and a poorly differentiated SCC, had been identified in 1 out of 14 excised cervical lymph nodes. The patient underwent external beam radiation without chemotherapy. She is still in stable condition at 18 months post-treatment. This case clearly demonstrated that SCC transformed from a pre-existing PTC. The clinician should consider a possible transformation of papillary thyroid cancer into more aggressive histological types in elderly patients who present with rapidly progressive clinical behavior. However, some patients could have long-term survival if the tumor did not transform into anaplastic thyroid cancer.

Citation

Yotsapon Thewjitcharoen, Sirinate Krittiyawong, Siriwan Butadej, Soontaree Nakasatien, Somsong Polchart, Pairoj Junyangdikul, Auchai Kanchanapituk, Thep Himathongkam. De-differentiation of papillary thyroid carcinoma into squamous cell carcinoma in an elderly patient: A case report. Medicine. 2020 Apr;99(16):e19892