(130) Although we do not advocate use of the oxymoronic term malignant blue nevus in practice, we have used it here to encompass 2 separate entities: a de novo melanoma that adopts a blue nevus-like morphology (blue nevus-like melanoma) and a melanoma arising within a preexisting blue nevus.
Atypical cellular blue nevi (cellular blue nevi with atypical features): lack of consensus for diagnosis and distinction from cellular blue nevi and malignant melanoma ("malignant blue nevus").
Melanoma associated with blue nevus and melanoma mimicking cellular blue nevus: a clinicopathologic study of 10 cases on the spectrum of so-called "malignant blue nevus." Am J Surg Pathol.
The ICD-O classification includes further morphological codes, such as balloon cell M, regressing M, amelanotic M, M in junctional nevus, M in precancerous melanosis, desmoplastic M, neurotropic M, mucosal lentiginous M, M in giant pigmented nevus/congenital melanocytic nevus, mixed epithelioid and spindle cell M, epithelioid cell M, spindle cell M (not otherwise specified), spindle cell M (type A), spindle cell M (type B), and malignant blue nevus
(14,15) Additionally, HMB45 may not be as useful in blue nevus-related lesions and malignant blue nevus
This type of melanoma resembling blue nevus (so-called malignant blue nevus
) sometimes arises in association with a blue nevus.
Based on this single case, it was suggested that malignant DPN may harbor a more favorable prognosis than conventional melanoma because of its low-grade malignant potential, akin to pigment-synthesizing melanoma or malignant blue nevus
. (13) In our view, it is impossible to draw conclusions based on a single case report and it is not possible to ascertain whether this case represents an ordinary melanoma or a true malignant DPN.
We discuss salient clinical and pathologic features of blue nevi, with emphasis on the most diagnostically challenging aspects involving recognition of some rare variants and differential diagnosis between atypical blue nevus and malignant blue nevus. The last section provides an update on the recent advances in understanding the molecular pathogenesis of blue nevi.
These features have to be distinguished from tumor necrosis, which can lead to diagnostic confusion with malignant blue nevus. (48,49) Cytologic features of melanocytes forming the cellular areas of CBN are quite characteristic.
The term atypical cellular blue nevus has been applied to rare CBNs that show atypical histologic features and raise histologic differential diagnosis of malignant blue nevus. (9,40,51-53) There are no established consensus criteria regarding this diagnostic category and there is poor consensus among experienced dermatopathologists and experts regarding classification of individual lesions along the CBN/atypical CBN/malignantblue nevus (melanoma arising in BN) diagnostic spectrum.
Artur Zembowicz, MD, PhD, and Pushkar Phadke, MD, PhD, review clinical and histologic features of blue nevus, cellular blue nevus, and malignant blue nevus
, emphasizing recently described variants and critical differential diagnoses.
So-called "malignant blue nevus
": a clinicopathologic study of 23 patients.