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PubMed This is a summary of 16 peer-reviewed journal articles Updated
Dermatology

Diagnosis and Look-Alikes: What It Is and Isn't

At a Glance

A Nevus of Ito is diagnosed by its distinct flat, blue-gray appearance on the shoulder or collarbone. Dermatologists easily distinguish it from similar marks like Nevus of Ota or Mongolian spots through a visual exam. Biopsies are rarely needed unless the patch develops a raised bump or changes.

Getting a diagnosis for a blue or gray skin patch involves distinguishing it from several similar-looking conditions. While a Nevus of Ito is usually identified by its location on the shoulder or collarbone, doctors use specific biological and visual clues to confirm what it is—and what it isn’t.

The Biological Root: A Migration “Pause”

To understand the diagnosis, it helps to understand the biology. During embryonic development, pigment cells (melanocytes) travel from the neural crest (a temporary group of cells in an embryo) to the surface of the skin [1][2].

In a Nevus of Ito, these cells are ectopic—meaning they are in the wrong place. They become “trapped” deep in the dermis (the thick middle layer of skin) instead of reaching the top layer [3][4]. This happens because of a specific genetic change in the cells called a mosaic mutation, typically in the GNAQ or GNA11 genes [5][6]. “Mosaic” means the mutation isn’t in every cell of your body—just in the patch of skin where the nevus appears.

Differentiating the “Look-Alikes”

Dermatologists carefully compare your skin patch against other forms of dermal melanocytosis.

Condition Primary Location Persistence Appearance
Nevus of Ito Shoulder, shoulder blade, collarbone [3] Permanent [7] Flat, blue-gray patch [3]
Nevus of Ota Face, near the eye/temple [8] Permanent [9] Flat, blue-gray patch [10]
Mongolian Spot Lower back, buttocks [11] Usually fades by age 3–5 [11] Flat, blue-gray patch [11]
Blue Nevus Can be anywhere [12] Permanent Often a nodule (raised bump) [6]

Nevus of Ito vs. Nevus of Ota

These two are “cousins.” They look identical under a microscope but live in different areas of the body. While Ito stays on the shoulder and arm, Nevus of Ota follows the path of the trigeminal nerve on the face [8][10]. It is possible, though rare, for a person to have both [4].

Nevus of Ito vs. Blue Nevus

A Blue Nevus is usually a small, distinct, and often raised bump or nodule [6]. In contrast, a Nevus of Ito is a large, flat “patch” that feels just like the surrounding skin [3].

The Role of Biopsy

In most cases, a dermatologist can diagnose a Nevus of Ito simply by looking at it and reviewing your history (a clinical diagnosis). A biopsy—where a small piece of skin is removed and examined under a microscope—is usually not necessary [13].

However, a doctor may recommend a biopsy if:

  1. The patch develops a new, raised bump (nodularity) [5][14].
  2. The colors become very uneven or change rapidly [5].
  3. The diagnosis is uncertain between a flat patch and a more aggressive type of blue nevus [15][14].

Under the microscope, a Nevus of Ito shows long, wavy, “dendritic” (branch-like) pigment cells scattered among the normal fibers of the deep skin layer [3][4].

Diagnosis Completeness Checklist

If you are seeking a formal diagnosis, ensure your care team has checked the following:

  • [ ] Visual Exam: Has the doctor checked the shoulder, neck, and upper arm?
  • [ ] Facial Check: Has the doctor checked the eyes and face for a concurrent Nevus of Ota? (You can have both at the same time) [8]
  • [ ] Texture Check: Is the area completely flat to the touch?
  • [ ] History: Was the mark present at birth or did it appear around puberty? [4]
  • [ ] Dermoscopy: Did the doctor use a handheld lighted magnifier (dermoscope) to look at the pigment patterns? [16]

Back to Home | Next: Treatment Options

Common questions in this guide

How is a Nevus of Ito diagnosed?
Dermatologists usually diagnose a Nevus of Ito by examining the flat, blue-gray patch on your shoulder or collarbone. They will review your medical history and may use a lighted magnifier called a dermoscope to look at the pigment patterns.
What is the difference between a Nevus of Ito and a Nevus of Ota?
Both conditions look identical under a microscope, but they appear on different parts of the body. A Nevus of Ito is found on the shoulder, collarbone, or arm, while a Nevus of Ota appears on the face, often near the eye or temple.
Do I need a biopsy to confirm a Nevus of Ito?
In most cases, a biopsy is not necessary for a diagnosis. However, your doctor may recommend one if the skin patch develops a raised bump, changes color rapidly, or has uneven coloring that makes the diagnosis uncertain.
Will a Nevus of Ito fade over time like a Mongolian spot?
No, a Nevus of Ito is a permanent skin patch. While Mongolian spots typically appear on the lower back and fade during early childhood, a Nevus of Ito remains on the skin permanently.
What changes in my skin patch should I watch out for?
If your blue or gray patch develops a new raised bump, rapidly changes color, or develops highly uneven colors, you should have it evaluated by a doctor. These changes could indicate the need for a biopsy.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Is this a flat patch (Ito) or a raised nodule (Blue Nevus), and how does that change the diagnosis?
  2. 2.Given that this is likely a genetic 'mosaic' condition, should we be looking for any other related symptoms?
  3. 3.Are the borders and color of this lesion consistent with a typical Nevus of Ito?
  4. 4.If we were to do a biopsy, what specific findings would confirm Ito over its look-alikes?
  5. 5.Do you see any signs of 'nodularity' that would make a biopsy necessary right now?

Questions For You

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References

References (16)
  1. 1

    Polarity and migration of cranial and cardiac neural crest cells: underlying molecular mechanisms and disease implications.

    Salinas E, Ruano-Rivadeneira F, Leal JI, et al.

    Frontiers in cell and developmental biology 2024; (12()):1457506 doi:10.3389/fcell.2024.1457506.

    PMID: 39834387
  2. 2

    Mechanisms of Neural Crest Migration.

    Szabó A, Mayor R

    Annual review of genetics 2018; (52()):43-63 doi:10.1146/annurev-genet-120417-031559.

    PMID: 30476447
  3. 3

    [Treatment of nevus of Ota and Ito and epidermal nevus syndrome].

    Badawi A, Osman MA, Kassab AN

    Der Hautarzt; Zeitschrift fur Dermatologie, Venerologie, und verwandte Gebiete 2020; (71(12)):926-931 doi:10.1007/s00105-020-04710-3.

    PMID: 33145623
  4. 4

    Case report: nevus of Ota and nevus of Ito associated with meningeal melanocytosis.

    Nuñez Del Arco Serrano LA, Flores Enderica CG, Valencia Padilla CE

    Neurocirugia 2020; (31(6)):299-305 doi:10.1016/j.neucir.2019.10.001.

    PMID: 31780112
  5. 5

    Melanoma arising in a nevus of Ito: novel genetic mutations and a review of the literature on cutaneous malignant transformation of dermal melanocytosis.

    Tse JY, Walls BE, Pomerantz H, et al.

    Journal of cutaneous pathology 2016; (43(1)):57-63 doi:10.1111/cup.12568.

    PMID: 26260725
  6. 6

    Molecular alterations in malignant blue nevi and related blue lesions.

    Yilmaz I, Gamsizkan M, Sari SO, et al.

    Virchows Archiv : an international journal of pathology 2015; (467(6)):723-732 doi:10.1007/s00428-015-1851-3.

    PMID: 26403583
  7. 7

    Patchy Dermal Melanocytosis: Differential Diagnosis and Management.

    Zhu J, Cen Q, Chang R, et al.

    Journal of cosmetic dermatology 2025; (24(1)):e16607 doi:10.1111/jocd.16607.

    PMID: 39485055
  8. 8

    Oculodermal Melanocytosis: Nevus of Ota in a Dog.

    Giannikaki S, Sturgess K, Scurrell E, et al.

    Veterinary pathology 2019; (56(3)):460-464 doi:10.1177/0300985818823667.

    PMID: 30686121
  9. 9

    Ocular Features in a Case of Nevus of Ota.

    Junejo MS, Khan MS, Mukhtar A

    Journal of the College of Physicians and Surgeons--Pakistan : JCPSP 2017; (27(3)):S56-S57 doi:255.

    PMID: 28302248
  10. 10

    Giant nevus of Ota.

    Rishi P, Rishi E, Bhojwani D

    Indian journal of ophthalmology 2015; (63(6)):532-3 doi:10.4103/0301-4738.162607.

    PMID: 26265645
  11. 11

    Dermal melanocytosis and associated disorders.

    Franceschini D, Dinulos JG

    Current opinion in pediatrics 2015; (27(4)):480-5 doi:10.1097/MOP.0000000000000247.

    PMID: 26087431
  12. 12

    An Orbital Malignant Melanoma Arising in Cellular Blue Nevus in a Patient with Nevus of Ota.

    Buntinx-Krieg T, Ouyang J, Cartwright M

    Cureus 2016; (8(7)):e698 doi:10.7759/cureus.698.

    PMID: 27699140
  13. 13

    Surgical histopathology of limited dorsal myeloschisis with flat skin lesion.

    Morioka T, Suzuki SO, Murakami N, et al.

    Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery 2019; (35(1)):119-128 doi:10.1007/s00381-018-3870-2.

    PMID: 29934704
  14. 14

    Melanocytic Nevus of the Superior Conjunctival Fornix: A Case Report.

    Adetunji MO, Cummings TJ, Materin MA, Maniar AS

    Case reports in ophthalmology 2024; (15(1)):225-229 doi:10.1159/000537876.

    PMID: 38500543
  15. 15

    Giant Blue Nevus: A New Association to Nevus of Ota.

    Medel R, Vasquez L, Fernandez J, et al.

    Orbit (Amsterdam, Netherlands) 2015; (34(4)):223-8 doi:10.3109/01676830.2015.1049372.

    PMID: 26121271
  16. 16

    Acquired dermal melanocytosis on the hand of a pediatric patient.

    Marín-Hernández E, Marín-González EJ, Siordia-Reyes G

    Boletin medico del Hospital Infantil de Mexico 2019; (76(6)):294-297 doi:10.24875/BMHIM.19000135.

    PMID: 31769440

This page is for informational purposes only and does not replace professional medical advice. Always consult a dermatologist for a proper diagnosis of any new or changing skin patches.

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