Clinical stage of merkel cell carcinoma and survival are not associated with breslow thickness of biopsied tumor

Background Merkel cell carcinoma (MCC) is an aggressive malignancy that often presents on the skin with concurrent metastatic disease. Objective To determine whether Breslow thickness of biopsied MCC correlates with clinical disease stage. Materials and Methods We performed a retrospective review of clinical data and histopathology specimens from 34 individuals with MCC treated at the Roswell Park Cancer Institute for whom complete clinical information and histopathology specimens were available. Results There was no correlation between Breslow thickness of biopsied MCC on the head and neck or body and clinical stage of disease, progression-free survival, or overall survival. Hence, thin MCCs should not be taken to represent lesions with less-aggressive clinical behavior. Conclusion Our findings validate the current practice of staging all newly diagnosed MCC, irrespective of size or Breslow thickness.