Epidermal Growth Factor Receptor Expression in Spindle Cell Carcinomas of the Head and Neck

Abstract

Spindle cell carcinoma (SpCC) is an uncommon head and neck squamous cell carcinoma (SCC) variant consisting of spindled and/or pleomorphic cells with epithelial differentiation. Epidermal growth factor receptor (EGFR) is expressed by >90 % of conventional SCC, and high level expression is associated with a poorer prognosis. Anti-EGFR therapies are commonly used to treat head and neck SCC. However, no studies have evaluated EGFR expression in SpCC. Cases of SpCC were retrieved from department files. The diagnosis required either a biphasic lesion with a squamous neoplastic component, or a purely spindle cell or pleomorphic tumor with immunohistochemical positivity for epithelial markers. EGFR immunohistochemistry was performed and was quantified in quartiles. Medical records were reviewed for clinical follow up information. EGFR was expressed in 21/30 (70 %) cases, including in the squamous component in 18/19 (95 %) and the spindle cell component in only 12/30 (40 %). Where the spindle cell component was positive, the intensity and distribution were lower than for the squamous component. Recurrent tumors were predominantly (80-90 %) of the spindle cell component, and had low (or absent) EGFR expression. Kaplan-Meier survival analysis showed no statistically significant differences in overall or disease free survival between the EGFR expressing and non-expressing groups (p = 0.414 and 0.19, respectively). SpCCs of the head and neck have a poor prognosis, and markedly reduced EGFR expression. EGFR-specific therapies may not be ideal for SpCC patients, which may lack EGFR expression, but further studies are needed.

Fig. 1

Histologic features of SpCC and EGFR immunohistochemistry. a A classically biphasic SpCC with both conventional SCC and spindle cell components (H&E; ×100 magnification). b The same SpCC showing a keratinizing-type squamous cell carcinoma (left side) and a pleomorphic, spindle cell component (right side) with variably-sized and shaped, hyperchromatic nuclei with prominent fibrous stroma and prominent mitoses (H&E; ×400). c The tumor shows diffuse cytoplasmic positivity for EGFR in the conventional SCC component (×400). d The tumor shows almost absent EGFR staining with both low distribution and intensity (×400). SpCC spindle cell carcinoma, SCC squamous cell carcinoma, EGFR epidermal growth factor receptor

Fig. 2

Kaplan–Meier survival analysis of spindle cell carcinoma by EGFR status and component EGFR status. a Overall survival by EGFR status. b Disease-free survival by EGFR status. c Overall survival by the EGFR status of just the spindle cell component. d Disease-free survival by the EGFR status of just the spindle cell component. EGFR epidermal growth factor receptor