Dysplastic nevi, cutaneous melanoma, and other skin neoplasms in patients with myotonic dystrophy type 1: A cross-sectional study

Background Myotonic dystrophy type 1 (MD1) is reported to be associated with internal malignancies. The association of myotonic dystrophy with cutaneous tumors is not fully understood. Objective We sought to explore the total nevi count and the presence of atypical nevi, cutaneous melanoma, and other skin neoplasms in a representative cohort of patients with MD1 and to compare the findings with age- and sex-matched control subjects. Methods In all, 90 patients with MD1 and 103 age- and sex-matched control subjects were assessed for cutaneous neoplasms by clinical skin and epiluminescence examination (dermoscopy). Where indicated, subsequent excisions were performed. In patients with MD1, leukocyte n(CTG) expansion was measured. Results Patients with MD1 showed significantly higher numbers of nevi, dysplastic nevi, and melanomas despite a significantly greater proportion of the control subjects reporting sunburns. In addition, we found a significantly greater number of pilomatrixoma in patients with MD1. Limitations Our study is limited by the fact that there is no agreed-upon standardized technique to assess for prior sun exposure. Further research in the association of cutaneous neoplasms and MD1 including vitamin D and molecular biological techniques are also recommended. Conclusion MD1 itself may predispose to development of skin tumors.