Benign and Malignant Cellular Blue Nevus A Clinicopathological Study of 30 Cases

Oral Atypical Cellular Blue Nevus: An Infiltrative Melanocytic Proliferation

“…As the size increases from [3 cm [23] to [6 cm [3], melanoma is reported to be more likely. Lesions falling within the 1-2 cm range (our case was 1.7 cm) have been reported for CBN [2,4] as well as for MBN [9] such that size is not discriminatory in our case.…”

“…While rare to absent in CBN [2], mitotic activity is nearly always seen in MBN [10,11], though at a variable rate. While mitotic rates often overlap in ACBN and MBN [8,18,19,22], the presence of mitotic activity in atypical blue nevi is associated with unfavorable biologic behavior [21] and multiple groups have reported that atypical mitoses are a feature of malignancy [4,9,11,13,28]. Our case lacked atypical cytologic features as may occur in ACBN.…”

“…While necrosis may be seen in MBN, it is not observed in the majority of cases [9,11,14], though other groups report that it is invariably found [29]. Necrosis has been reported in some cases of ACBN [17] and in a small percent of CBN [4]. Therefore, while necrosis suggests a more aggressive process, it is not entirely specific for malignancy.…”

“…The cellular portion contains ovoid to spindleshaped melanocytes with small nucleoli and variable pigmentation [2,3]. Mitotic activity can be seen (B2 mitoses/ mm 2 ) while necrosis as well as junctional activity or epidermal invasion are typically absent [2,4]. Following conservative excision, long-term follow-up data indicate a very small risk for recurrence and no metastasis [2].…”

“…In some instances, a blue nevus (most often CBN) is associated with a malignant melanoma and is referred to as malignant blue nevus (MBN), blue nevus-like melanoma or malignant melanoma arising in a blue nevus [4,[8][9][10][11][12][13][14]. When unquestionably malignant features such as widespread necrosis, mitotic activity, atypical mitoses and marked cytologic atypia are juxtaposed next to an otherwise bland CBN, the diagnosis is straightforward.…”