The anatomic distribution of melanoma and relationships with childhood nevus distribution in Colorado.

The nature of the relationship between nevus development in childhood and later development of melanoma is unclear. Data on melanoma diagnoses by histologic type and anatomic site were obtained for 2351 white, non-Hispanics in Colorado from the Colorado Central Cancer Registry between 2000 and 2004. Nevus size and body site were ascertained during skin exams conducted in the summer of 2007 on 717 white, non-Hispanic children aged 8-9 years. Chi-square goodness-of-fit analysis was used to assess the association between the anatomic site distributions of nevi versus melanoma. Superficial spreading melanoma was the most frequent histology, followed by lentigo maligna melanoma. Nodular melanoma was the least common histology. For males, there was no significant difference between the distribution of medium-sized (> or =2 mm) nevi and the distribution of both superficial spreading and nodular melanomas. For females, there was no significant difference between the anatomic distribution of small-sized (<2 mm) nevi and the distribution of nodular melanoma, and there was marginal evidence for a difference between the distribution of medium-sized (> or =2 mm) nevi and the distribution of nodular melanoma. There was evidence for a difference between all of the nevus distributions and the distributions of superficial spreading and lentigo maligna melanoma in females. The similarities between the nevus and melanoma distributions are interesting findings, but it is difficult to interpret the significance of these findings based on the current state of knowledge of melanoma etiology.