Skin melanocytic tumor

Blue nevi, dermal melanocytoses and associated neoplasms

Dermal melanocytosis



Topic Completed: 23 July 2021

Minor changes: 8 November 2021

Copyright: 2013-2021, PathologyOutlines.com, Inc.

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

Christopher S. Hale, M.D.
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Cite this page: Hale CS. Dermal melanocytosis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skintumormelanocyticdermalmelanocytosis.html. Accessed November 27th, 2021.
Ito's nevus
Definition / general
  • First described by Minor Ito in 1954

Terminology

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

Treatment

Clinical images

Images hosted on other servers:
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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

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

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:
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Flat blue-gray pigmentation

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Acquired dark brown spots below eyes

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Episcleral involvement

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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.
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Elongated dendritic melanocytes scattered with collagen bundles extending around hair follicles



Images hosted on other servers:
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Bipolar dendritic
melanocytes in
papillary and
reticular dermis

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Wavy dendritic
cells with evenly
dispersed
melanin granules



Differential diagnosis
Mongolian spot
Definition / general

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

Sites
  • Usually sacral region

Case reports

Treatment

Clinical images

Images hosted on other servers:
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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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