Malignant Blue Nevus: Clinicopathologically Similar to Melanoma

Abstract

Malignant blue nevus (MBN) is a rare melanocytic lesion and controversy exists whether it is a melanoma or a unique entity. We sought to establish clinical behavior using a large national registry. All patients with MBN and melanoma from 1973 to 2008 were identified in the Surveillance Epidemiology and End Results tumor registry. We performed comparative and survival analysis among the two tumor types. A total of 228,038 patients were identified (227,986 with melanoma and 52 with MBN). The mean age was 57.7 years. Both lesions had similar age of presentation (55.8 vs 55.7 years, P = 0.527), sex (male 50 vs 55%, P = 0.44), and nodal positivity rate (9.6 vs 5.4%, P = 0.22). MBNs were more likely to be nonwhite (11.8 vs 1.6%, P < 0.0001) and present with metastatic disease (15.2 vs 4%, P = 0.0028). MBN and melanoma had a similar survival (264 vs 240 months, P = 0.78) and remained similar when stratified by race (264 vs 242 months, P = 0.99) and stage (264 vs 256 months, P = 0.83). This is the largest study to date demonstrating similar clinical behavior and survival between patients with MBN and those with melanoma. We believe MBN is a variant of melanoma and suggest using a similar treatment algorithm as that of melanoma.

Malignant Blue Nevus Arising in a Congenital Cellular Blue Nevus in a Young Woman: Case Report and Review of Literature

“…Demographic profiles of MBN are still not well established due to its low incidence, small series studied and variations in the definition of the lesion made by different authors. MBN can occur at any age, but is mostly reported in middle-aged adults [4,16]. In the series analyzed by Kachare SD, et al the average age at presentation was 55.8 years and, in the series reported by Martin RCW, et al the average age was 44 years [2,16].…”

“…MBN can occur at any age, but is mostly reported in middle-aged adults [4,16]. In the series analyzed by Kachare SD, et al the average age at presentation was 55.8 years and, in the series reported by Martin RCW, et al the average age was 44 years [2,16]. It is reported that MBN occurs almost equally frequent in men and women [16], however some studies report higher incidence in male patients [2].…”

“…Histopathologically, both melanomas and MBN may exhibit multiple similar features: cytologic atypia, pleomorphism, increased mitotic activity, abnormal mitotic figures, necrosis, vascular invasion, expansile or destructive growth, and infiltrative margins [4,7,20]. In addition, MBN display the presence of a concomitant or pre-existing blue nevus which, by definition, does not involve epidermis (which is not typical for melanoma) [16]. However, in one of the best documented morphological case studies so far, by Granter SR, et al (2001), not all of the malignant features were consistently present in adverse outcome cases, with some metastasizing cases lacking features such as necrosis, significant atypical, or the presence of more than 2 mitosis/mm 2 .…”

“…However, in one of the recent study analysis of 23 MBN cases, no difference in survival or in the risk of lymph node or distant metastases was observed between patients with MBN and a matched control group of melanoma patients, after a median follow-up of 36.5 months [2]. MBN are diagnosed generally with greater tumor thickness then other types of melanoma, but this does not seem to reflect in higher propensity to lymph node metastases or in decreased survival [2,16]. Additionally, the latest and the largest study on MBN to date, which included 52 patients with MBN, demonstrated similar clinical behavior and survival between patients with MBN and those with melanoma, even though MBN were more likely to present with metastatic disease then melanomas (15.2% vs. 4%, P=0.0028) [16].…”

“…MBN are diagnosed generally with greater tumor thickness then other types of melanoma, but this does not seem to reflect in higher propensity to lymph node metastases or in decreased survival [2,16]. Additionally, the latest and the largest study on MBN to date, which included 52 patients with MBN, demonstrated similar clinical behavior and survival between patients with MBN and those with melanoma, even though MBN were more likely to present with metastatic disease then melanomas (15.2% vs. 4%, P=0.0028) [16]. On the other hand, both groups (MBN and melanomas) had similar age of presentation (55.8 vs. 55.7, respectively, P=0.527), gender distribution (male 50% vs. 55%, P=0.44), and nodal positivity rate (9.6% vs. 5.4%, P=0.22) [16].…”