Original articleCharacteristics, treatment, and survival of invasive malignant melanoma (MM) in giant pigmented nevi (GPN) in adults: 976 cases from the National Cancer Data Base (NCDB)

BackgroundMalignant melanoma (MM) arising in a giant pigmented nevus (GPN) is a rare disease in adults with no large series published to our knowledge.ObjectiveWe sought to describe the characteristics, treatment, and survival of MM in GPN for adults.MethodsAdults with invasive MM in GPN (n = 976) reported to the National Cancer Data Base from 1998 to 2012 were evaluated for patient and tumor characteristics, treatment, and survival. For comparison, data from adults with invasive superficial spreading melanoma (SSM) (n = 111,870) and nodular melanoma (n = 35,962) were used.ResultsCompared with patients with SSM, patients with MM in GPN had a thicker Breslow depth, more positive lymph nodes, and distant metastasis more frequently. Multivariate analysis identified age older than 65 years, Breslow thickness greater than 2 mm, presence of ulceration, presence of distant metastasis, and positive margins as independent predictors of survival in patients with MM in GPN. At all stages, having MM in GPN has similar overall survival compared with SSM.LimitationsThe study is retrospective and registry-based.ConclusionsInvasive MM in GPN occurs in adults, with overall survival similar to SSM. Clinicians should be aware of the continued risk of MM in adults with GPN with low threshold for biopsy.