Pure squamous cell carcinoma and mixed adenosquamous cell carcinoma of the thyroid gland

Abstract

Four cases of pure squamous cell carcinoma and two cases of mixed squamous cell and glandular carcinoma are reported. Obviously, there is a possibility that squamous cell carcinoma of the thyroid gland develops from the existing squamous cells or as a result of metaplasia of follicular cells. Metastases and direct extension of squamous cell carcinoma in the thyroid gland are much more frequent and must be excluded before the diagnosis can be established. Although the gross and microscopic pathology of these lesions presents no unusual features, follicles lined by metaplastic squamous cells offer strong presumptive evidence of a primary thyroid neoplasm. These tumors are comparatively radioresistant and biologically highly malignant. The treatment of choice is radical surgical resection, and these neoplasms must be treated more aggressively in the initial stage.

Primary Squamous Cell Carcinoma of the Thyroid Gland With Eggshell Calcification

“…We diagnosed it as malignancy before surgery on the basis of the presence of peripheral hypoechoic soft tissue and disruption of the eggshell calcification, consistent with the findings of Kim et al 5 Squamous cell epithelium may appear in a normal thyroid gland and in various pathologic conditions, both non-neoplastic and neoplastic. 12 Two hypotheses about the etiology of this condition have been proposed, including the "metaplasia theory" (squamous metaplasia of underlying thyroid disease) and the "embryonic nest theory" (squamous cells originating from a remnant of an ultimobranchial duct or a thyroglossal duct). 1 In our case, there was no associated thyroiditis, adenomatous goiter, or carcinoma of other histologic types and no evidence of a remnant of an ultimobranchial duct or a thyroglossal duct was found on pathologic examination.…”

“…12 Evaluation of this disease involves a combination of endoscopy and radiographic examination by CT to exclude SCC that has spread from the adjacent upper aerodigestive tract sites, as well as metastasis from distant sites such as the lung, gastrointestinal tract, and genitourinary tract. 1,10,14 Histopathologic diagnosis requires microscopic identification of keratin or intercellular bridge structures.…”

Particularités cliniques et thérapeutiques des carcinomes épidermoïdes de la thyroïde : étude de cinq cas

“…Les adénopathies cervicales sont présentes dans 25 % des cas [3,14]. Les métastases sont fréquentes et touchent surtout le poumon (observation n o 5).…”

A Patient with Primary Squamous Cell Carcinoma of the Thyroid Intermingled with Follicular Thyroid Carcinoma that Remains Alive more than 8 Years after Diagnosis

“…A normal thyroid has no squamous cells; however, a diseased thyroid may contain them. Primary squamous cell carcinoma of the thyroid may develop from squamous metaplasia of the follicular epithelium in a variety of pathologic conditions, such as, other differentiated carcinomas of the thyroid1, 6, 9-14). Thyroid carcinoma commonly presents as sudden enlargement of a neck mass with associated pressure symptoms.…”