Less aggressive disease in patients with primary squamous cell carcinomas of the thyroid gland and coexisting lymphocytic thyroiditis

Abstract

Aim of the studyPrimary squamous cell carcinoma (SCC) of the thyroid gland is extremely rare. Infrequently, primary SCC of the thyroid gland is accompanied by other thyroid diseases such as Hashimoto's thyroiditis (HT). Recently, studies have demonstrated that differentiated thyroid cancer with coexisting HT has a better prognosis. However, the prognosis of patients with primary SCC of the thyroid gland and coexistent HT has not been clearly identified. We compared the clinical characteristics and disease stages of patients with primary SCC with and without lymphocytic thyroiditis (LT).Material and methodsWe reviewed reports of primary SCC of the thyroid gland published in the English literature.Results and conclusionsWe identified 46 papers that included 17 cases of primary SCC of the thyroid gland with LT and 77 cases of primary SCC of the thyroid gland without LT. Lymph node metastasis and local invasion rates did not differ between these two groups. Distant metastases were absent in patients with LT, and were observed in 13 (16.9%) patients without LT. A greater proportion of patients without LT had advanced stage disease (stage IV A-B-C) than patients with LT (p < 0.05). Patients with primary SCC of the thyroid gland and coexisting LT had lower tumour-node-metastasis stage and frequency of distant metastasis than those without LT. Lymphocytic infiltration in patients with SCC appears to limit tumour growth and distant metastases.

Primary squamous cell carcinoma of the thyroid: Case report and systematic review of the literature

“…Some 17 publications with 48 cases without complete work-up, including CT-scan, panendoscopy, immunohistochemistry and double citations were excluded [6] , [7] , [8] , [9] , [10] , [11] , [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] , [22] . Finally, 35 papers and ours reporting on 50 patients were available for analysis [2] , [3] , [4] , [5] , [6] , [7] , [8] , [9] , [10] , [11] , [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] , [24] , [25] , [26] , [27] , [28] , [29] , [30] , [31] , [32] , [33] , [34] , [35] , [36] , [37] , [38] , [39] , [40] , [41] , [42] , [43] , [44] , [45] , [46] , [47] , [48] , [49] , ...…”

Clinical analysis of 13 cases of primary squamous-cell thyroid carcinoma

“…Various hypotheses have been proposed, including the embryonic nest theory, postulating that squamous cells originate from remnant cells from the thyroglossal duct or thymic epithelium ( 8 ). Alternatively, the theory of dedifferentiation has been put forward, suggesting the idea that PSCTC may have been dedifferentiated from other adenocarcinomas ( 9 ). Thewjitcharoen (2020) reported a case of a 79-year-old female patient who had undergone PTC surgery and then relapsed with a diagnosis of PSCTC, validating the theory of dedifferentiation described above ( 10 ).…”

Squamous cell carcinoma of thyroid: a unique type of cancer in World Health Organization Classification

“…Lymphocytic infiltration including Hashimoto's thyroiditis are commonly associated with thyroid carcinomas and lymphomas (Lam et al 1999b, Molnár et al 2019). Asik and colleagues analysed the cases reported in the literature and noted that primary thyroid squamous cell carcinoma of thyroid with concurrent lymphocytic thyroiditis had lower pathological stages and frequency of distant metastases (Asik et al 2015). In the current review, patients having primary thyroid squamous cell carcinoma with concurrent lymphocytic thyroiditis had slightly better survival rates than those patients without concurrent lymphocytic thyroiditis.…”