Squamous Differentiation in Thyroid Carcinoma With Special Reference to Histogenesis of Squamous Cell Carcinoma of the Thyroid

Abstract

Squamous differentiation of thyroid carcinoma was studied clinicopathologically and immunohistochemically i n 29 autopsy cases. Tumor cell nests with squamous differentiation (CNSD), which histologically resembled squamous cell carcinoma, were found i n 6 cases (20.7%). All of these 6 cases with CNSD had areas of undifferentiated carcinoma, representing 31.6% of 19 cases with undifferentiated carcinoma, and all but one case also showed coexisting papillary carcinoma. The CNSD were histologically associated with undifferentiated carcinoma in 5 cases, and with papillary carcinoma in one case; the CNSD were occasionally intermingled with these types of carcinoma, and there were findings suggesting a histological transition between the CNSD and undifferentiated carcinoma or papillary carcinoma. lmmunohistochemistry revealed that all the CNSD were reactive with antibodies for keratin and vimentin, whereas thyroglobulin and desmin were not expressed. It was concluded that the CNSD examined here were most probably due to extensive squamous differentiation (squamous metaplasia) i n undifferentiated carcinoma and papillary carcinoma. I n addition, the present results may explain the fact that cases diagnosed solely as squamous cell carcinoma sometimes show a prognosis similar to that of undifferentiated carcinoma, and may well represent extensive squamous differentiation i n such tumors rather than true squamous cell carcinoma of the thyroid. Acta Pathol Jpn 39: 306 -312, 1989.

Cytological findings of intrathyroidal epithelial thymoma/carcinoma showing thymus‐like differentiation: A study of eight cases

“…We observed that both squamous differentiation and mucin‐producing cells were observed in two cases of ITET/CASTLE. Squamous differentiation has been described in papillary carcinoma, SCC, MEC, and AC 14–18. Mucin‐producing cells may be seen in papillary carcinoma, FC, MC, MEC, and metastatic adenocarcinoma 19–23.…”

Neoexpression of the epithelial adhesion complex antigens in thyroid tumours is associated with proliferation and squamous differentiation markers

“…Squamous differentiation of papillary and anaplastic thyroid carcinomas was also observed in routine histological studies. 34,35 Interestingly, it has been suggested earlier that the expression of type VII collagen in carcinomas would correlate more with the presence of squamous differentiation than the histogenetic origin of the tumour. 18 In agreement with our results, while this manuscript was under review, the expression of typical stratified epithelial cks 5/6 and 13 in papillary thyroid carcinomas was reported.…”

Primary squamous‐cell carcinoma of the thyroid gland: New evidence in support of follicular epithelial cell origin

“…15 This definition of SCC is quite important, since up to 43% of papillary carcinomas will contain regions of squamous-cell metaplasia, and many anaplastic carcinomas will be comprised, in part, of squamoid regions. 9,16 Using these strict criteria, the incidence of SCC of the thyroid is less than 1% of all thyroid malignancies. 17,18 The origin of primary SCC within the thyroid remains controversial, and several hypotheses have been proposed.…”