Primary Squamous Cell Carcinoma of the Thyroid Diagnosed as Anaplastic Carcinoma: Failure in Fine-Needle Aspiration Cytology?

Abstract

A case of primary squamous-cell carcinoma (SCC) of the thyroid which had been initially diagnosed as an anaplastic carcinoma (ATC) is described: female, 73 years old, with a fast-growing cervical nodule on the left side and hoarseness for 3 months. Ultrasonography showed a 4.5 cm solid nodule. FNA was compatible with poorly differentiated carcinoma with immunoreactivity for AE1/AE3, EMA. Thyroidectomy was performed. Histopathological examination showed a nonencapsulated tumor. Immunohistochemistry disclosed positivity for AE1/AE3, p53,p63, and Ki67. The diagnosis was ATC. A second opinion reported tumor consisting of squamous cells, with intense inflammatory infiltrate both in tumor and in the adjacent thyroid, with final diagnosis of SCC, associated with Hashimoto thyroiditis. No other primary focus of SCC was found. Patient has shown a 48-month survival period. Clinically, primary SCCs of the thyroid and ATCs are similar. The distinction is often difficult particularly when based on the cytological analysis of FNA material.

Cytologic features of aggressive variants of follicular‐derived thyroid carcinoma

“…[108][109][110][111][112] ATC accounts for less than 5% of thyroid cancers, with a peak incidence in the 6th to 7th decades. [108][109][110][111][112][113][114][115][116][117][118][119][120][121][122] The majority of cases are fatal, often between 6 months and 1 year after presentation, with a median 1-year survival rate of only 10% to 20%. The typical clinical appearance is that of an older patient with a rapidly enlarging firm and fixed infiltrative anterior neck mass.…”

“…ATC is defined as a high-grade pleomorphic and epithelial-derived malignancy with epithelial and spindle features. [112][113][114][115][116][117][118] Cytological samples show variable cellularity, but most FNA cases are moderately or highly cellular ( Fig. 9).…”

“…Anaplastic thyroid carcinoma (ATC) is recognized as one of the most aggressive primary thyroid malignancies . ATC accounts for less than 5% of thyroid cancers, with a peak incidence in the 6th to 7th decades . The majority of cases are fatal, often between 6 months and 1 year after presentation, with a median 1‐year survival rate of only 10% to 20%.…”

“…It is important to differentiate ATC from other malignant entities such as PDTC, MTC, melanoma, lymphoma, sarcoma (especially for those ATCs with predominant spindle features), and metastatic tumors . ATC is usually negative for TTF‐1 and thyroglobulin.…”

Pierwotny rak płaskonabłonkowy tarczycy – opis przypadku skutecznego leczenia z 5-letnią obserwacją

“…Based on the clinical symptoms, it is nearly impossible to distinguish SCTC from anaplastic cancer [7]. Predictability of diagnosis of SCTC with fine-needle aspiration biopsy is accurate in less than one-third of patients [1,2,6,[8][9][10][11]. As the disease progresses, dysphagia and hoarseness may occur [9].…”