[1296] CD34 and α-SMA Distinguish Verrucous Hyperplasia from Verrucous Carcinoma

Kristen M Paral, Lei Zhao, Mark Lingen, Jerome B Taxy. University of Chicago, Chicago, IL

Background: Distinguishing between verrucous carcinoma (VC) and verrucous hyperplasia (VH) is a diagnostic challenge. The determination relies heavily upon whether the lesion lies above or below a line connecting the uninvolved epithelium on either side of the lesion. This feature may be difficult or impossible to evaluate due to failure of the surgeon to excise widely enough or technical difficulties with embedding and cutting. Epithelial features do not clearly resolve the issue, as both lesions are devoid of cytologic criteria for malignancy. Previous studies have demonstrated key differences in the stroma of benign and malignant squamous lesions. Stroma associated with invasive carcinoma is characterized by a loss of CD34+ fibrocytes with a gain of SMA+ myofibroblasts; opposite reactions are seen in uninvolved stroma. We employ these principles to determine whether VC and VH can be distinguished.
Design: Nine VH, 14 VC, and 14 conventional infiltrating keratinizing squamous cell carcinomas were retrieved from the surgical pathology files. Tissue stroma was assessed for reactivity with anti-CD34 antibody (Novocastra, NCL-END, mouse IgG, 1:25 dilution) and anti-α-SMA antibody (DAKO, M0851, mouse IgG, 1:100 dilution). Tumor-free stroma was also assessed in 12 of these cases.
Results:

Table 1. Stromal Staining Patterns Among Groups
GroupsnSMA+CD34+
Tumor-free120.0%100.0%
Verrucous hyperplasia90.0%100.0%
Verrucous carcinoma1492.9%14.3%
Squamous cell carcinoma14100.0%0.0%




Upper left: Classic VC. Middle left: A network of slender, bipolar SMA+ myofibroblasts ensheathes the rete pegs. Bottom left: Stromal cells are negative for CD34. Upper right: Classic VH. Middle right: Stromal cells are negative for SMA. Bottom right: The delicate CD34+ meshwork is seen in continuity with non-tumoral stroma at the right. Only one outlier VC case stained exactly opposite to the other VC cases. This case had no uninvolved adjacent epithelium to evaluate.
Conclusions: The present series suggests a discriminating role for the use of CD34 and α-SMA to distinguish VH from VC with very high sensitivity and specificity. The presence of a single outlier VC case, albeit without accompanying normal adjacent epithelium, raises the possibility of reconsidering the current histologic diagnostic criteria for VC.
Category: Head & Neck

Wednesday, March 6, 2013 9:30 AM

Poster Session V # 196, Wednesday Morning

 

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