Clinical characteristics of Merkel cell carcinoma at diagnosis in 195 patients: the AEIOU features

Merkel cell carcinoma (MCC) is an aggressive skin cancer with a mortality of 33%. Advanced disease at diagnosis is a poor prognostic factor, suggesting that earlier detection may improve outcome. No systematic analysis has been published to define the clinical features that are characteristic of MCC. Objective To define the clinical characteristics present at diagnosis in order to identify features that may aid clinicians in recognizing MCC. Methods Cohort study of 195 patients diagnosed with MCC between 1980 and 2007. Data were collected prospectively in the majority of cases, and medical records were reviewed. Results An important finding was that 88% of MCCs were asymptomatic (nontender) despite rapid growth in the prior 3 months (63% of lesions) and being red or pink (56%). A majority of MCC lesions (56%) were presumed to be benign, with a cyst/acneiform lesion being the single most common diagnosis (32%) given at biopsy. The median delay from lesion appearance to biopsy was 3 months (range 1–54 months), and median tumor diameter was 1.8 cm. Similar to prior studies, 81% of primary MCCs occurred on UV-exposed sites, and our cohort was elderly (90% over age 50), predominantly Caucasian (98%), and often profoundly immune suppressed (7.8%). An additional novel finding was that chronic lymphocytic leukemia was more than 30-fold over-represented among MCC patients. Limitations The study was limited to patients seen at a tertiary care center. Complete clinical data could not be obtained on all patients. This study could not assess the specificity of the clinical characteristics of MCC. Conclusions This study is the first to define clinical features that may serve as clues in the diagnosis of MCC. The most significant features can be summarized in an acronym: AEIOU -Asymptomatic/lack of tenderness, Expanding rapidly, Immune suppression, Older than age 50, and UV-exposed site on a person with fair skin. In our series, 89% of primary MCCs had three or more of these findings. Although MCC is uncommon, when present in combination, these features may indicate a concerning process that would warrant biopsy. In particular, a lesion that is red and expanding rapidly yet asymptomatic should be of concern.