Master Melanocytic Nevus (Mole) with Picmonic for Medicine

With Picmonic, facts become pictures. We've taken what the science shows - image mnemonics work - but we've boosted the effectiveness by building and associating memorable characters, interesting audio stories, and built-in quizzing.

Melanocytic Nevus (Mole)

Melon-side-toe-Beavis and Mole-head
tantheman
9 KEY FACTS
GENERAL CHARACTERISTICS
Benign Tumor of Melanocytes
Benign-bunny and melon

Melanocytic nevi, or moles, consist of a benign proliferation of melanocytes in the skin. Recall that melanocytes produce the pigment melanin. Melanocytes that are not part of a melanocytic nevus typically reside within the basal layer of the epidermis and are organized in a single layer, whereas melanocytes that are part of a nevus are clustered in nests within the epidermis or dermis. Melanocytes that help form a nevus are also sometimes referred to simply as "nevus cells". 

Arranged In Nests at Dermal-Epidermal Junction and Within Dermis
Nests of melons by e-pick-deer-mouse and deer-mouse

While melanocytes not involved in the formation of nevi are arranged in a single layer along the basal membrane of the epidermis, nevus cells (melonocytes that form part of a nevus) are arranged as clusters or nests along the dermal-epidermal junction and within the dermis. The resulting nevi are referred to as junctional and intradermal nevi respectively. 

Intradermal Nevi Are Papular and Flesh-Colored
Flesh-colored plaque-people

Nevi formed by melanocytes clustered together within the dermis, referred to as intradermal nevi, appear grossly as flesh-colored papules. Intradermal nevus cells typically lose their ability to produce melanin, hence therefore they will have a similar pigmentation as the surrounding skin. 

Junctional Nevi Are Macular and Dark
Dark-mac at junction

Junctional nevi, which are composed of nevus cells located at or near the dermal-epidermal junction, are characteristically macular, or flat, and dark in color. The dark pigmentation is conferred by melanin. 

PREDISPOSING FACTORS
Genetics
Genetic-mutant

Genetics play a large role in the predilection of an individual to develop congenital or acquired melanocytic nevi. Multiple genes have been implicated, such as interferon regulatory factor 4 (IRF4) and telomerase reverse transcriptase (TERT).

Sun Exposure During Childhood
Child tanning

Degree of sun exposure during childhood plays a role in the development of melanocytic nevi. Particularly, intense and intermittent exposure is thought to increase incidence. 

Skin Tone
Leg darker than rest of body

Skin tone is also correlated with the number of nevi an individual may develop, with lighter-skinned individuals tending to possess 3-5 times as many nevi as darker skinned individuals. 

CONSIDERATIONS
Potential to Become Melanoma
Melon-gnome above surface

Although the vast majority of nevi a person has remain benign, each one carries a small potential risk of becoming a melanoma, which is malignant. It is important to remember however that over half of melanomas arise de novo, i.e., not in association with any nevus. Although each nevus carries this small risk, it is not recommended that unremarkable nevi be removed prophylactically. Instead, individuals with many nevi are advised to receive routine full-body skin examinations on a regular basis. 

ABCDEs of Melanoma
ABCDE's of Melon-gnome

The mnemonic "ABCDE" can be used to recall characteristics to look out for when identifying moles that may be suspicious and require further workup. 

A: Asymmetry. Moles that appear asymmetric. 

B: Borders. Irregular or blurred borders. 

C: Color. A mole comprised of more than one color. 

D: Diameter. Moles >6mm. 

E: Evolution. Moles that change over time in size, shape, or color. 

Unlock all 9 facts & definitions with Picmonic Free!

JOIN FREE

Take the Melanocytic Nevus (Mole) Quiz

Picmonic's rapid review multiple-choice quiz allows you to assess your knowledge.

START QUIZ NOW

It's worth every penny

Our Story Mnemonics Increase Mastery and Retention

Memorize facts with phonetic mnemonics

Unforgettable characters with concise but impactful videos (2-4 min each)

Ace Your Medical (MD/DO) Classes & Exams with Picmonic:

Over 1,050,000 students use Picmonic’s picture mnemonics to improve knowledge, retention, and exam performance.

Choose the #1 Medical (MD/DO) student study app.

Picmonic for Medical (MD/DO) covers information that is relevant to your entire Medical (MD/DO) education. Whether you’re studying for your classes or getting ready to conquer the USMLE Step 1, USMLE Step 2 CK, COMLEX Level 1, or COMLEX Level 2, we’re here to help.

Works better than traditional Medical (MD/DO) flashcards.

Research shows that students who use Picmonic see a 331% improvement in memory retention and a 50% improvement in test scores.