Becker Melanosis (Nevus)

Question 1

Define main clinical features

Answer 1

Unilateral, hyperpigmented, often hypertrichotic patch or slightly elevated plaque.

Question 2

What is most common site involved ?

Answer 2

Shoulder of male patients

Question 3

When do Becker nevus usually appear ?

Answer 3

2-3 decades (10-30) / adolescence

Question 4

True or false

Six times more common in males

Answer 4

True

Question 5

Pathogenesis is unclear. Wjat are the main postulations that could explain its onset during or after puberty as well as its histologic and clinical manifestations that include hypertrichosis, dermal thickening, acne, and hypertrophic sebaceous glands ?

Answer 5

• *increase in androgen receptors
• *probable heightened sensitivity to androgens.
• *androgen stimulations could also explain the accentuated smooth muscle elements found in the dermis of Becker melanosis

Question 6

When somebody presents with becker nevus , what to ask him about in terms of exposure ?

Answer 6

Intensw Sun exposure sometimes precedes appearance.

Question 7

Does becker nevus present as unilateral or multiple lesions ?

Answer 7

Unilateral

Question 8

What is the most common area of involvement ? ( written in text)

Answer 8

Upper quadrant of the anterior or posterior chest .
See fig 112.2 page 1956
מתואר על פני עור חזה עליון שטח יונילטרלי היפרפיגצמנטרח בגוון חום בהיר עם איזור מתמזג במרכז ושוליים בלתי סדירים ומקוטעים ( irregular broken up border ) .

לפעמים יש גם היפרטריכוזיס בתמונה B , בה לחולה היה גם underlying smooth muscle hamadtoma.

Other areas have been described that can be misdiagnosed as CALMs or congenital melanocytic nevus.

Question 9

What is the range of sizes ?

Answer 9

Few cms to >15 cm

Question 10

Most common configuration

Answer 10

Block like

Linear patters has been reported

Question 11

Lesion characteristics

Answer 11

Well demarcated
Margins are usually irregular
Hypertrichosis ( not always overlaps with pigmentation area)
May enlarge slowly for a year and then remains stable in size

Question 12

Does it itch ?

Answer 12

No

It is asymptomatic but some patients report pruritus

Question 13

What is a sign of associated smooth muscle hamartoma ?

Answer 13

Firmness to palpation

Question 14

What are the developmental anomalies that have occasionally been associated with becker nevus ? ( Becker nevus syndrome)

Answer 14

Soft tissue and bony abnormalities

See text copy later dor details

Question 15

Pathology

Answer 15

Copy from text later

Question 16

Differential diagnosis of becker nevus ?

Answer 16

# CALM
# congenital melanocytic nevus
# plexiform neurofibroma
# congenital smooth muscle hamartoma
The latter tends to be smaller in size but some authors consider becker Melanosis and smooth muscle hamartoma to be two ends of a clinical spectrum.

Question 17

What are the lesions in the dd that can have both hyperpigmentation as well as hypertrichosis ?

Answer 17

Congenital melanocytic nevus
Plexiform neurofibroma
Congenital smooth muscle hamartoma

Question 18

Dermoscopy

Answer 18

Refer to text

Question 19

How to differentiate between the dd ?

Answer 19

Multiple CALMS plus axillary freckling can be helpful in establishing tge diagnosis of neurofibromatosis

See text for dermoscopy to compare with congenital melanocytic nevi

Unlike becker nevus, CALM do not have corrugation on side-lighting

Question 20

When to biopsy ?

Answer 20

In occasional patient
Unusual location
And there is an associated smooth muscle hamartoma

Question 21

Treatment for hyperpigmentation?

Answer 21

May respond to Q-switched ruby and frequency-doubled Nd:Yag laser therapy but recurrence rates are high.