Intermediate filament proteins in spindle cell carcinoma of the larynx and tongue

Abstract

In an analysis of intermediate filament protein expression of spindle cell carcinoma, a variant of squamous cell carcinoma, occurring in larynx and tongue, vimentin positivity was found in sarcomatoid areas in 12 of 13 patients. Scattered expression of keratin was observed in sarcomatoid areas in tumours of 10 patients. However, large parts of sarcomatoid areas of such tumours were negative for keratin. Overlying dysplastic epithelium and squamous cell carcinoma components were positive for keratin. In a number of cases there was a strong indication of co-expression of keratin and vimentin in parts of cells that, on histological grounds, belong to sarcomatoid areas or to cells in the interface between carcinoma and spindle cell area. The use of keratin and vimentin type intermediate filament antibodies could be of great help for the correct classification of these tumours.

Sarcomatoid (Spindle Cell) Carcinoma of the Head and Neck Mucosal Region: A Clinicopathologic Review of 103 Cases from a Tertiary Referral Cancer Centre

“…The degree and intensity of epithelial marker expression is also reported to vary [3] as was observed in our study as well. Immunopositivity with any of the epithelial markers was observed in 53.4% of cases in our study, comparable to reported figures of between 48 and 75% [3,17,19,23,[25][26][27]. This may be due to a number of technical and histological factors as detailed by Thompson et al [3] which include subjectivity in interpretation, sampling error, nonhomogeneous tumors, poor preservation or fixation, inappropriate antibody or technique, or epithelial features less than the threshold of detection.…”

“…Sarcomatoid carcinoma contains both a conventional epithelial squamous component and a sarcomatous spindle cell component [2,3,[17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. As also noted in our study, epithelial differentiation evident within the tumor is reported to be highly variable with either changes in the overlying epithelium in the form of dysplasia or carcinoma in situ or as part of the infiltrating tumor [1][2][3].…”

“…As also noted in our study, epithelial differentiation evident within the tumor is reported to be highly variable with either changes in the overlying epithelium in the form of dysplasia or carcinoma in situ or as part of the infiltrating tumor [1][2][3]. The latter may be demonstrable at light microscopy or by the expression of epithelial markers at immunohistochemistry, electron microscopy or at the molecular level [2,3,[17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. The degree and intensity of epithelial marker expression is also reported to vary [3] as was observed in our study as well.…”

“…Both the sarcomatoid as well as conventional squamous carcinoma components have now been proven to arise monoclonally from a single stem cell, and there is further evidence to prove that the sarcomatoid component represents a dedifferentiation and suggests molecular progression of the conventional component [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. The clinical behavior of sarcomatoid carcinoma is however reported to parallel that of conventional squamous carcinoma with the outcome being determined by the location and clinical stage [2,3,19].…”

“…These tumors have now been proved to be monoclonal, evolving from conventional squamous carcinoma with dedifferentiation associated with sarcomatoid transformation [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. They pose a significant diagnostic challenge to the pathologist with remarkable morphological and immunohistochemical overlap with other benign and malignant spindle cell tumors [1,3].…”