Rare Case of Squamous Cell Cancer From Aggressive Papillary Thyroid Carcinoma
Posted: Tuesday, July 14, 2020
Although papillary thyroid carcinoma is generally associated with a good prognosis, its clinical behavior varies and may be difficult to predict, especially in elderly patients. Thep Himathongkam, MD, of the Theptarin Hospital, Bangkok, and colleagues reported a rare case of an elderly patient who initially presented with typical papillary thyroid carcinoma and later showed evidence of de-differentiation into squamous cell carcinoma, suggesting tumor intermingling. These findings were reported in Medicine.
“De-differentiation from well-differentiated thyroid cancer into poorly differentiated thyroid cancer…is frequently reported with [a] dismal prognosis,” stated the authors. “As the tumor cells de-differentiated, cancer becomes resistant to the traditional therapeutic strategies.”
The team tracked a 79-year-old female patient through high-dose radioactive iodine treatment following a total thyroidectomy. Two years later, the patient presented with a recurrent mass and was once again treated with surgery and radiation. Six months after the second tumor recurrence, she presented with another neck mass and swollen lymph nodes. The neck mass and lymph nodes were pathologically examined and excised for immunohistochemical analyses.
Examinations revealed poorly differentiated squamous cell carcinoma in the neck mass and in 1 of 14 excised cervical lymph nodes. Staining revealed P63 (a well-known marker of squamous differentiation) and positive results for paired-box gene 8 in both papillary and squamous components, suggesting tumor intermingling. Although this case provides evidence that papillary carcinoma can transform to squamous carcinomas, further testing is still needed to determine the molecular pathways involved. According to the study authors, this is necessary “…to determine a novel targeted therapy based on molecular characterization of the tumor.”
Disclosure: The study authors reported no conflicts of interest.