Nuclear morphometry identifies a distinct aggressive cellular phenotype in cutaneous squamous cell carcinoma.

By identifying aggressive cutaneous squamous cell carcinoma (cSCC) in patients who are at high risk for recurrences or second primaries after resection, intensive surveillance and therapy may decrease morbidity and mortality. We investigated the role of nuclear morphometry (karyometry) in differentiating between aggressive and nonaggressive cSCC. We retrospectively analyzed cSCC lesions from 40 male patients. Twenty-two patients had evidence of aggressive cSCC (local/regional recurrence or a second primary cSCC), and 18 patients were identified with similar ages and sites of disease as control patients with nonaggressive cSCC (no evidence of recurrence, metastasis, or second primary). We carried out karyometric analysis to identify nuclear features that discriminate between aggressive and nonaggressive cSCC nuclei. We used statistically significant differences (Kruskal-Wallis test, P < 0.0001) to compose a quantitative aggressive classification score (proportion of aggressive nuclei from 0% to 100%). For comparisons, we used Fisher's exact test or Student's t test. The mean age was 79 ± 7 years for aggressive cSCC and 80 ± 9 years for nonaggressive cSCC (P = 0.66). We analyzed a mean of 96 nuclei in each group. The mean classification score for aggressive cSCC was significantly higher (69% ± 6%) than for nonaggressive cSCC (28% ± 5%, P = 0.00002). Overall, the classification score accurately categorized 80% of our patients (P = 0.0004). In most patients, karyometry differentiated between aggressive and nonaggressive cSCC. We found that classification scores, which provide information on individual lesions, could be used for risk stratification.