Skin melanocytic tumor
Topics to be merged
Nodular melanoma
Author: Christopher S. Hale, M.D.
Topic Completed: 1 May 2013
Minor changes: 4 November 2020
Copyright: 2002-2021, PathologyOutlines.com, Inc.
PubMed Search: Nodular melanoma
Table of Contents
Definition / general | Epidemiology | Sites | Clinical features | Case reports | Dermoscopy | Dermoscopic images | Clinical images | Microscopic (histologic) description | Microscopic (histologic) images | Molecular / cytogenetics description | Differential diagnosisCite this page: Hale CS. Nodular melanoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skintumormelanocyticnodularmelanoma.html. Accessed January 22nd, 2021.
Definition / general
- Aggressive subtype of melanoma with early vertical growth phase
Epidemiology
- Median age 63 years; men > women
Sites
- Affects all body surfaces, but usually legs and trunk
Clinical features
- Screening methods have had little impact on this subtype (Cancer 2008;113:3341); may have less of an association with sun exposure than superficial spreading subtype (Melanoma Res 2012;22:460)
- 15 - 30% of melanoma patients, but 37% of fatal melanomas (Arch Dermatol 2012;148:30)
- Rapid growth; comprises 34% of thick (2 mm+) melanomas (Arch Dermatol 2005;141:745)
- Higher risk for metastases due to vertical growth phase, but differs from "vertical growth melanoma" (J Dermatol 2008;35:643)
- May recur even in sentinel lymph node negative patients (Surgeon 2006;4:153)
- Smooth nodule covered by normal epidermis, elevated bluish black plaque or ulcerated polypoid mass
- Usually no lateral flat component
Case reports
- 29 year old man with 25 cm tumor on lower back (Dermatol Online J 2007;13:7)
- 34 year old woman with metastatic amelanotic tumor during pregnancy (Medicina (Kaunas) 2008;44:467)
- With Spitz nevus like features (J Dermatol 2007;34:821)
Dermoscopy
- Nonspecific global dermoscopic patterns of globules, bluish white veil, atypical vessels and structureless areas (Arch Dermatol 2008;144:1311)
- Important features: peripheral black dots / globules, multiple brown dots, irregular black dots / globules, bluish white veil, homogeneous blue pigmentation, 5 to 6 colors and black color (JAMA Dermatol 2013;149:699)
Dermoscopic images
Images hosted on other servers:
Atypical globular pattern (fig 1A)
Nonspecific pattern (fig 5A)
Clinical images
Images hosted on other servers:
25 cm tumor
Microscopic (histologic) description
- No radial growth phase
- Epidermis is thin and may be ulcerated
- No in situ melanoma
- Dermal component consists of a cohesive nodule of tumor cells with pushing border
- Cells are most commonly epithelioid, may be spindled or small with occasional monster cells (Am J Dermatopathol 2005;27:208)
Microscopic (histologic) images
Contributed by John Irlam, D.O.
Low power (4×)
Medium power (10×)
Medium power (20×)
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High power (40×)
Images hosted on other servers:
Hyperkeratosis without pagetoid spreading (fig 1C)
Noncoalescence atypical melanocytes (fig 5B)
Fig 6B and 6C
Poor differentiation
Ki67 staining
Molecular / cytogenetics description
- BRAF and NRAS mutations in 25 - 30% (J Invest Dermatol 2005;125:312)
- miRNA expression profile is distinct from other melanoma subtypes (J Invest Dermatol 2012;132:1860)
Differential diagnosis
- Primary dermal melanoma: no in situ component, ulceration, regression or associated nevus (Arch Dermatol 2008;144:49)
