Lindsay OConnor

Actinic keratoses (AKs) are precancerous, dysplastic epidermal lesions with potential for progression to squamous cell carcinoma (SCC). A study by Criscione et al¹ revealed that in a high-risk population (≥2 keratinocyte carcinomas in previous 5 years), approximately 65% of all primary SCCs arose in lesions previously diagnosed as AKs. Furthermore, it demonstrated that the risk of malignant progression of AKs to primary SCC increases over time (0.6% at 1 year and 2.6% at 4 years).¹ Cellular damage and atypia seen histologically in AKs are similar to those of surrounding nonlesional skin,^2,3 suggesting that skin surrounding AKs may have an increased risk of skin cancer.

Multiple primary melanomas (MPMs) have been reported to occur in 2-10% of melanoma patients. This study conducted a review of the literature to elucidate the definitions of terminology used to describe MPMs that were diagnosed in close temporal proximity as well as explore common risk factors. Terminology found in the literature included “concurrent”, “simultaneous” and “synchronous” with varying definitions that ranged from 0-6 months between diagnoses of the first and subsequent melanomas. Eight cases are described in chronological order, and the incidence of MPMs diagnosed around the same time were reported as 22-39%. Nevus spilus was identified as a potential risk factor for MPMs. This study highlights that MPMs are not uncommon, and clinicians should remain aware that MPMs can be diagnosed at or around the same time, warranting thorough skin exams.