Pigmented Lesions: Congenital

Question 1

CONGENITAL NEVOMELANOCYTIC NEVI (CNMN)

Clinical Feature

Answer 1

• sharply demarcated pigmented papule or plaque with regular borders ± coarse hairs
• classied by size: small (<1.5 cm), medium (M1: 1.5-10 cm, M2: >10-20 cm), large (L1: >20-30 cm, L2
>30-40 cm), giant (G1: >40-60 cm, G2: >60 cm)
• may be surrounded by smaller satellite nevi

Question 2

CONGENITAL NEVOMELANOCYTIC NEVI (CNMN)

Pathophysiology

Answer 2

Pathophysiology

• nevomelanocytes in epidermis (clusters) and dermis (strands)

Question 3

CONGENITAL NEVOMELANOCYTIC NEVI (CNMN)

Epidemiology

Answer 3

• present at birth or develops in early infancy to childhood
• malignant transformation is rare (1-5%) and more correlated with size of the lesion
• neurocutaneous melanosis can occur in giant CNMN (melanocytes in the CNS)

Question 4

CONGENITAL NEVOMELANOCYTIC NEVI (CNMN) Management

Answer 4

• take a baseline photo and observe lesion for change in shape, colour, or size out of proportion of growth
• surgical excision if suspicious, due to increased risk of melanoma
• MRI if suspicious for neurological involvement

Question 5

Which is this following lesion? Brown pigmented
macular
background (caféau-
lait macule-like)
with dark macular
or papular
speckles

Answer 5

Speckled
Lentiginous
Nevus (nevus
spilus)

Question 6

Which is this following lesion?
Congenital greyblue
solitary or
grouped macules
commonly on
lumbosacral area

Answer 6

Dermal
Melanocytosis
(historically
known as
Mongolian Spot)

Question 7

Which is this following lesion? Flat light brown
lesions with
smooth or jagged
borders

Answer 7

Café-au-lait

Macule

Question 8

Café-au-lait

Macule . Pathophysiology

Answer 8

Areas of
increased
melanogenesis

Question 9

Café-au-lait

Macule. Epidemiology

Answer 9

6 or more is
suggestive of
neurofibromatosis
type I
Also associated
with McCune-
Albright syndrome

Question 10

Café-au-lait
Macule. Clinical Course and
Management

Answer 10

Enlarge in proportion
to the child
No effective treatment

Question 11

Dermal

Melanocytosis. Pathophysiology

Answer 11

Ectopic
melanocytes in
dermis

Question 12

Dermal

Melanocytosis. Epidemiology

Answer 12

99% occurs
in Asian and
Indigenous infants

Question 13

Dermal
Melanocytosis. Clinical Course and
Management

Answer 13

Usually fades in early
childhood but may
persist into adulthood

Question 14

Speckled
Lentiginous
Nevus (nevus
spilus). Pathophysiology

Answer 14

Increased
melanocyte
concentration

Question 15

Speckled
Lentiginous
Nevus (nevus
spilus). Epidemiology

Answer 15

Risk of melanoma
similar to that of
a CNMN of the
same size

Question 16

Speckled
Lentiginous
Nevus (nevus
spilus). Clinical Course and
Management

Answer 16

Usually the light
macular background
is present at birth
and speckles develop
over time
Management is
similar to that of
CNMNs