Tumor cell anaplasia and multinucleation are predictors of disease recurrence in oropharyngeal squamous cell carcinoma, including among just the human papillomavirus-related cancers

Abstract

Oropharyngeal squamous cell carcinoma (SCC) is frequently related to high risk human papillomavirus. This tumor expresses p16, frequently has a nonkeratinizing morphology, and has improved outcomes. Despite having a good prognosis, tumors can have focal or diffuse nuclear anaplasia or multinucleation, the significance of which is unknown. From a database of 270 oropharyngeal SCCs with known histologic typing (using our established system) and p16 immunohistochemistry, all surgically resected cases (149) were reviewed. Anaplasia was defined as any × 40 field with ≥ 3 tumor nuclei with diameters ≥ 5 lymphocyte nuclei (~25 μm), and multinucleation was defined as any × 40 field with ≥ 3 tumor cells with multiple nuclei. p16 was positive in 128 cases (85.9%), 64 cases (43.0%) showed anaplasia, and 71 (47.7%) showed multinucleation. Anaplasia and multinucleation were highly related (P<0.001), and both also correlated with histologic type (P<0.001 and P=0.01, respectively), p16 status (P=0.09 and 0.03, respectively), and partially with nodal extracapsular extension. There was no correlation with any of the other variables. In univariate analysis, cases showing anaplasia or multinucleation had worse overall, disease-specific, and disease-free survival (P<0.006 for all). Higher T-stage, keratinizing histologic type, extracapsular extension, and smoking also all correlated with worse survival. In multivariate analysis, anaplasia and multinucleation both predicted worse disease-specific survival (hazard ratio 9.9, P=0.04; and hazard ratio 11.9, P=0.02, respectively) independent of the other variables. In summary, among surgically resectable oropharyngeal SCC (including among just the p16-positive cohort), tumor cell anaplasia and multinucleation independently correlated with disease recurrence and poorer survival.

FIGURE 1

Histologic types of oropharyngeal SCC, all lacking tumor cell anaplasia and multinucleation. A, Keratinizing-type SCC (type 1) showing angulated tumor nests in a desmoplastic stroma and with tumor cells showing abundant eosinophilic (keratinized) cytoplasm with patchy formation of actual keratin. B, NK SCC with maturation (“hybrid” or type 2) showing a tumor composed of large nests with rounded/smooth contours with little to no stromal reaction and composed predominantly of cells with little cytoplasm and hyperchromatic, round to oval nuclei with inconspicuous nucleoli. There is >10% maturing squamous differentiation with foci where the tumor cells have more abundant, eosinophilic cytoplasm. These maturing areas are predominantly at the periphery of the nests (so-called “reverse maturation”). C, NK SCC consisting of large nests of basophilic tumor cells with smooth borders and little to no stromal reaction. The tumor cells have round to oval, hyperchromatic nuclei with inconspicuous nucleoli and little cytoplasm. No significant maturing squamous differentiation is present (all images are at 200X magnification and hematoxylin and eosin stained).

FIGURE 2

Tumor cell anaplasia, defined as ≥ 3 tumor cell nuclei in one HPF, which are equal to or wider than 5 lymphocyte nuclei (~25 μm) in diameter. A, A single high-power field of NK SCC (type 3) with 3 anaplastic tumor nuclei (arrows) in a background of smaller tumor nuclei. B, A single high-power field of a keratinizing-type SCC (type 1) with >3 anaplastic tumor nuclei (arrows) (both images at 400X magnification and are hematoxylin and eosin stained).

FIGURE 3

Tumor cell multinucleation, defined as ≥ 3 tumor cell nuclei in one HPF which are definitively multinucleated. A, A single high-power field of NK SCC (type 3) with 3 multinucleated tumor cells (arrows). B, A single high-power field of a maturing area of a NK SCC with maturation (type 2) with >3 multinucleated tumor cells (arrows) (both images are at 400X magnification and hematoxylin and eosin stained).

FIGURE 4

Kaplan-Meier univariate survival analysis for tumor cell anaplasia—(A) overall survival; (B) disease-free survival; (C) disease-specific survival; and for tumor cell multinucleation—(D) overall survival; (E) disease-free survival; (F) disease-specific survival.

FIGURE 5

Kaplan-Meier univariate survival analysis for cases by tumor p16 immunohistochemical status, with the p16-positive cases further divided into those with the presence or absence of anaplasia and multinucleation—(A) overall survival; (B) disease-free survival; (C) disease-specific survival.