Histopathologic Features Predictive of Aggressiveness of Post-transplant Cutaneous Squamous-cell Carcinomas

Background. Squamous cell carcinomas (SCC), the commonest malignancies developing in organ-transplant recipients (OTR), may behave aggressively. We searched for pathological features of post-transplant SCC that could predict an aggressive outcome early. Materials and Methods. We pathologically examined 34 SCC developed in OTR that developed later recurrences/metastases, and compared them with 25 non-aggressive SCC excised from the same OTRs over the same period of time for features believed to predict an aggressive outcome (tumour size and thickness, ulceration, deep tissue invasion, mitotic rate, differentiation, peritumoural infiltrate density, acantholysis, perineural and lymphovascular invasion). Results. A statistically significant difference was found for the level of tumour invasion (Clark), as 58% (18/34) of aggressive SCCs (vs 24% (6/25) of non-aggressive SCCs) were of levels IV or V. Conclusion: Post-transplant SCCs with a Clark level of IV or V are associated with a higher risk for recurrence and metastasis and call for a close patient follow-up.