Nevoid Melanoma
Soheil Sam Dadras, MD, PhD
Key Facts
Terminology
Uncommon variant of conventional melanoma that looks deceptively benign
Clinical Issues
Melanoma is not suspected clinically
Microscopic Pathology
Dome shaped or verrucous
Exhibits pseudomaturation
Increased mitotic activity or proliferation index
Ancillary Tests
Immunostaining for Ki-67 (or MIB-1) to determine proliferation index (> 5-10% supports the diagnosis)
Top Differential Diagnoses
Intradermal melanocytic nevus
Congenital melanocytic nevus
Combined melanocytic nevus
 Nevoid melanoma is deceptively symmetrical appearing on low-power examination, mimicking a compound or intradermal nevus. |
 On high-power examination, numerous mitotic figures  are easily found in this nevoid melanoma. |
TERMINOLOGY
Synonyms
Some cases have been described as “minimal deviation melanoma,” but this term is very controversial and should be avoided
Definitions
Uncommon variant of melanoma that shows histological features mimicking a nevus
ETIOLOGY/PATHOGENESIS
Environmental Exposure
Likely solar/UV radiation related, similar to most types of melanoma
CLINICAL ISSUES
Presentation
Occurs in wide age range
Can be ubiquitous, but occurs more frequently on the back and extremities
Dome-shaped papule or nodule, or a verrucous lesion
Often not recognized clinically as melanoma
Can resemble a nevus or basal cell carcinoma
Treatment
Surgical approaches
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