Skin melanocytic tumor
Melanoma
Nevoid melanoma
Author: Christopher S. Hale, M.D.
Last author update: 1 May 2013
Last staff update: 25 November 2024 (update in progress)
Copyright: 2002-2024, PathologyOutlines.com, Inc.
PubMed Search: Nevoid melanoma
Table of Contents
Definition / general | Terminology | Epidemiology | Clinical features | Case reports | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Differential diagnosisCite this page: Hale CS. Nevoid melanoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skintumormelanocyticnevoidmelanoma.html. Accessed November 27th, 2024.
Definition / general
- Rare variant characterized by morphologic features of nevus (Hum Pathol 1995;26:171, Arch Dermatol Res 1985;277:362, Mod Pathol 2006;19:S41)
Terminology
- Synonym: "verrucous pseudonevoid melanoma"
- Distinct from controversial term "minimal deviation melanoma"
Epidemiology
- Adults in fifth decade
- No clear gender preponderance (Clin Dermatol 2009;27:564, Mod Pathol 2006;19:S41)
Clinical features
- Rare variant characterized by morphologic features of nevus
- Behavior similar to other melanomas; may recur or metastasize causing death (Am J Dermatopathol 2001;23:167)
- Key to diagnosis is high index of suspicion
- Dome shaped papule, nodule or verrucous lesion
- Tan nodule 1 cm or larger on trunk or proximal limbs of young adult
Case reports
- 4 year old girl with metastatic tumor to sentinel lymph node (J Cutan Pathol 2003;30:647)
- Multiple primary nevoid melanomas in HIV / AIDS patient (J Am Acad Dermatol 2002;47:S172)
Microscopic (histologic) description
- Resembles ordinary compound or dermal nevus at low power, with symmetrical dome shaped or verrucous and papillomatous features, sharp lateral demarcation, inconspicuous junctional component and no pagetoid growth
- High power shows relatively bland and monomorphic cells resembling classic nevus or epithelioid cells in Spitz nevus
- Focal sheetlike growth pattern, nucleoli in tumor cells at base of lesion
- Multiple dermal mitoses with atypical mitoses
- Subtle pleomorphism and impaired maturation with depth
Microscopic (histologic) images
Images hosted on other servers:
Lesion #1:
Various images
Lesion #2:
Various images
Lesion #3:
Various images
Atypical single cells
Mitotic figures
Positive stains
- HMB45 (strong throughout) (J Cutan Pathol 1995;22:502)
- Increased labeling index with Ki67
- Diffuse staining with cyclin D1
Differential diagnosis
- Melanoma arising in dermal nevus:
- Residual nevus present, often tumor extension into deep reticular dermis and fat
- Metastatic melanoma
- Minimal deviation melanoma:
- At most moderate atypia, at least level III due to dermal invasion, remnants of existing nevi usually present and usually few mitotic figures
- Nodular melanoma:
- High grade atypia, intraepidermal atypia
