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Skin melanocytic tumor

Blue nevi, dermal melanocytoses and associated neoplasms

Dermal melanocytosis

Last author update: 23 July 2021

Last staff update: 26 February 2024

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PubMed Search: Nevus of Ito [title], nevus of ota, Mongolian spot

Table of Contents

Ito's nevus | Nevus of Ota | Mongolian spot

Cite this page: Hale CS. Dermal melanocytosis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skintumormelanocyticdermalmelanocytosis.html. Accessed December 25th, 2024.

Ito's nevus

Definition / general

First described by Minor Ito in 1954

Terminology

More accurately grouped with dermal melanocytoses (nevus of Ito, nevus of Ota, Hori nevus, so called "Mongolian" spot) (eMedicine: Nevi of Ota and Ito [Accessed 23 July 2021])
Although melanocytic, it is not a true nevus
Different entity from Hypomelanosis of Ito, a neurocutaneous disorder (J Child Neurol 2000;15:635)

Epidemiology

Usually individuals with pigmented skin, most commonly Asians; also Hispanics, blacks, Native Americans
More common in women
Often occurs with nevus of Ota in same patient but is much less common

Sites

By definition, found in shawl or cloak distribution

Clinical features

Macule with irregular blue-gray pigmentation
Similar to nevus of Ota except for location
Ito’s nevus is found in shoulder, side of neck and supraclavicular areas, within the distribution of the lateral (also called posterior) supraclavicular nerve and lateral cutaneous brachial nerves
Nevus of Ota is found around the eyes

Case reports

38 year old man with nevus of Ota (Indian J Dermatol Venereol Leprol 2004;70:112)
72 year old woman with late onset Ito's nevus (J Cutan Pathol 2007;34:640)
With transformation to melanoma (J Am Acad Dermatol 2010;62:869)

Treatment

Laser to lighten pigment (cosmetic purposes)
Cryotherapy, dermabrasion, chemical peeling and surgical excision may give variable results (Facial Plast Surg Clin North Am 2007;15:367)

Clinical images

Images hosted on other servers:

Nevus of Ota (face) and nevus of Ito (shoulder)

Microscopic (histologic) description

Deeply pigmented dendritic melanocytes and melanophages dissecting bundles of dermal collagen in reticular dermis
Overlying epidermis is normal

Nevus of Ota

Definition / general

First described by Ota in 1939
Uncommon hamartoma in periorbital and temporal skin (eMedicine: Nevi of Ota and Ito [Accessed 23 July 2021])
Types:
- Type IA: mild orbital type - distribution over upper and lower eyelids, periocular and temple region
- Type IB: mild zygomatic type - pigmentation in infrapalpebral fold, nasolabial fold and zygomatic region
- Type IC: mild forehead type - involvement of forehead alone
- Type ID: involvement of ala nasi alone
- Type II: moderate type - distribution over upper and lower eyelids, periocular, zygomatic, cheek and temple regions
- Type III: involves scalp, forehead, eyebrow and nose
- Type IV: bilateral
- Hori’s nevus: acquired bilateral nevus of Ota-like macules (J Am Acad Dermatol 1984;10:961, Dermatol Online J 2005;11:1); usually Chinese women with family history, becomes more confluent and gray over time (Br J Dermatol 2006;154:50)
- Sun’s nevus: acquired unilateral nevus of Ota

Terminology

Also called oculodermal melanosis or nevus fuscoceruleus ophthalmomaxillaris
Similar to nevus of Ito except for location (Ito in shoulder, side of neck and supraclavicular areas, within the distribution of the lateral supraclavicular nerve and lateral cutaneous brachial nerves)

Epidemiology

Usually Asians; also Hispanics, blacks and Native Americans
60% have lesions at birth, 87% female, 60% have dermal and ocular involvement (Indian J Dermatol Venereol Leprol 2008;74:125)

Sites

Periorbital, temporal

Clinical features

Tends to persist and extend locally, becoming increasingly prominent with age, puberty and postmenopausal state
Associated with ipsilateral glaucoma, intracranial melanocytosis; rarely with cutaneous, ocular or intracranial melanoma and vascular nevus (Cutis 2008;82:25, J Am Acad Dermatol 2008;58:88)
Macule with irregular blue-gray pigmentation in distribution of 1st and 2nd division of trigeminal nerve
May coexist with nevus of Ito
Tanino classification system most common, others include Hirayama system and proposed Chan system (Lasers Surg Med 2001;28:267)

Case reports

30 year old woman with bilateral and oral mucosa involvement (Indian J Dermatol Venereol Leprol 2002;68:104)
41 year old woman with acquired bilateral nevus (Dermatol Online J 2005;11:1)
47 year old light-skinned non-Asian woman with bilateral manifestations (Dermatol Online J 2007;13:19)
50 year old man with coexisting iris melanoma (Surv Ophthalmol 2008;53:411)
Elderly Caucasian woman with acquired Ito's nevus (J Cutan Pathol 2007;34:640)

Treatment

Cosmetic coverup products
Multiple sessions of laser photothermolysis to avoid darkening and extension, beginning early after diagnosis (Dermatol Surg 2007;33:455)
Subtypes vary in response to laser therapy (Lasers Surg Med 2001;28:267)
Combined skin abrasion and carbon dioxide snow method (Plast Reconstr Surg 1996;97:544)
- Cryosurgery and microsurgery not recommended due to scarring; chemical bleaching not recommended due to depigmentation

Clinical images

Images hosted on other servers:

Flat blue-gray pigmentation

Acquired dark brown spots below eyes

Episcleral involvement

With nevus of Ito

Microscopic (histologic) description

Deeply pigmented dendritic melanocytes and melanophages dissecting bundles of dermal collagen in reticular dermis

Microscopic (histologic) images

Contributed by Asmaa Gaber Abdou, M.D.

Elongated dendritic melanocytes scattered with collagen bundles extending around hair follicles

Images hosted on other servers:

Bipolar dendritic
melanocytes in
papillary and
reticular dermis

Wavy dendritic
cells with evenly
dispersed
melanin granules

Differential diagnosis

Acquired bilateral nevus of Ota-like macule
Cafe-au-lait patch
Speckled lentiginous nevus

Mongolian spot

Definition / general

Ill defined area of blue discoloration, up to several centimeters and in lumbosacral region (eMedicine: Congenital Dermal Melanocytosis (Mongolian Spot) [Accessed 23 July 2021], Wikipedia: Mongolian spot [Accessed 23 July 2021])
May also occur at other sites
See also Ito’s nevus

Terminology

Also known as congenital dermal melanocytosis
Related to dermal melanocytoses (nevus of Ito, nevus of Ota, Hori nevus)
Although melanocytic, is not a true nevus

Epidemiology

Congenital disorder, present at birth in most neonates from Asia, East-Africa or Turkey; also Native Americans
Incidence of 60 - 70% in Iran, Nigeria and Taiwan (Pediatr Dermatol 2006;23:61, Niger J Med 2001;10:121, Chang Gung Med J 2007;30:220)
- Usually regresses over several years, almost always by puberty but may persist (Int J Dermatol 2005;44:43)
Usually not present in children with blond hair (Turk J Pediatr 2006;48:232)
Extensive Mongolian spots may be associated with inborn errors of metabolism (Pediatr Neurol 2006;34:143, Br J Dermatol 2003;148:1173)

Sites

Usually sacral region

Case reports

1 year old boy with facial lesion near mandibular area (J Dermatol 2007;34:381)
4 infants with darker pigmented Mongolian spot superimposed on another Mongolian spot (Pediatr Dermatol 2008;25:233)

Treatment

Wait for regression
Laser (Lasers Med Sci 2007;22:159)

Clinical images

Images hosted on other servers:

Mongolian spots

Microscopic (histologic) description

Normal at low power
High power shows occasional deep dendritic melanocytes, with melanin granules dissecting bundles of dermal collagen
No associated melanophages

Differential diagnosis

Bruises from child abuse

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