Nodular melanomas associated with nevi

Abstract

To the Editor: Nodular melanoma (NM) represents approximately 9% to 15% of invasive melanomas. The histopathologic definition of NM is based on the absence of a radial growth phase. Most frequently, it manifests itself in midlife with a median age at presentation of 53 years, and it is more common in males than in females. In 11% to 25% of the cases, NM is histologically associated with nevi. We report the experience of the Melanoma Unit of University Hospital Spedali Civili of Brescia, Italy. Between January 1, 1982 and October 1, 2009, 95 patients with cutaneous NM were identified from a group of 1865 patients with histologically confirmed melanoma; the incidence was 5.1% (95/1865). Of the 95 patients evaluated, 49 (51.6%) were males and 46 (48.4%) were females. All patients were white. The average age was 54.5 years (range, 15-91). Primary melanomas were found in different body sites as follows: eight (8.4%) lesions were on the head and neck, 32 (33.7%) on the trunk, 22 (23.2%) on the upper extremities, and 33 (34.7%) on the lower extremities. The lesions appeared most frequently on the trunk in male patients and on the lower extremities, upper extremities, and trunk in female patients. None of our 95 cases had a documented family history of melanoma. With regard to invasive melanomas, Breslow thickness ranged from 0.5 mm to 11 mm, with a mean thickness of 3.9 mm. The mean Breslow thickness was 4.4 mm in male patients and 3.4 mm in female patients. Ten out of 95 patients (10.5%) showed histologic evidence of an associated nevus; five patients were male and five were female. The average age of these 10 patients was 55.9 years. In seven patients, melanoma arose in association with an acquired nevus (2 dysplastic nevus and 5 other acquired nevi). In the remaining three patients, melanoma arose in association with a small congenital nevus. When examined by anatomic location, one lesion was on the head and neck, five were on the trunk, one was on the upper extremities, and three were on the lower extremities. The mean Breslow thickness for these 10 patients was 2.3 mm. When comparing the two groups (NM vs NM associated with nevi), the second group showed a thinner Breslow thickness (4.04 mm vs 2.3 mm). Our findings support the belief that in most cases, NM arises in absence of a precursor lesion. NM often fails to exhibit the original ABCD diagnostic criteria,