Skin melanocytic tumor
Melanoma
Melanoma arising in blue nevus


Topic Completed: 1 September 2014

Minor changes: 30 March 2020

Copyright: 2003-2020, PathologyOutlines.com, Inc.

PubMed Search: malignant blue nevus

Christopher S. Hale, M.D.
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Cite this page: Hale CS. Melanoma arising in blue nevus. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/skintumormelanocyticbluenevusmalignant.html. Accessed May 26th, 2020.
Definition / general
  • Very rare
  • Melanoma arising in background of cellular or common blue nevus or resembling a blue nevus
Terminology
  • Some authors prefer “melanoma associated with / arising within blue nevus” or “blue nevus-like melanoma” (Am J Dermatopathol 2004;26:407)
  • Atypical cellular blue nevus is defined as atypia insufficient for definitive diagnosis of malignancy
Epidemiology
Sites
Prognostic factors
  • May be present for many years before rapid growth occurs
  • Highly aggressive (Am J Surg Pathol 2001;25:316); may recur locally, extend into brain (if from scalp or eyelids), metastasize and cause death
  • Lung and lymph nodes are common sites of metastasis, also liver and bone (Am J Surg Pathol 2001;25:316)
Case reports
Treatment
  • Excise and examine carefully
Microscopic (histologic) description
  • Expansile asymmetric nodule with benign component OR low power benign features plus infiltrative borders, necrosis, mitoses or atypical cytologic features
  • May have epithelioid features with large hyperchromatic nuclei, prominent nucleoli and cytoplasmic melanin
  • Note: benign cellular blue nevus may involve lymph node parenchyma and sinuses in a metastatic-like pattern; some blue nevi are best classified as having “uncertain biologic behavior"
Microscopic (histologic) images

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Various images


Molecular / cytogenetics description
  • One study showed different allelic patterns at hOGG-1 locus between melanoma and control skin, with varying heterozygous allelic patterns in benign and malignant blue nevus (J Cutan Pathol 2008;35:651), but another study of eight genes (MTS1, MXI1, CMM1, p53, NF1, L-myc hOGG1 and MCC) showed no loss of heterozygosity (Am J Dermatopathol 2003;25:21)
Differential diagnosis
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