eMedicine Specialties > Dermatology > Benign Neoplasms

Cutaneous Melanoacanthoma

Author: Robert A Schwartz, MD, MPH, Professor and Head, Dermatology, Professor of Pathology, Pediatrics, Medicine, and Preventive Medicine and Community Health, UMDNJ-New Jersey Medical School
Coauthor(s): W Clark Lambert, MD, PhD, Professor and Head, Dermatopathology, Departments of Pathology and Dermatology, UMDNJ-New Jersey Medical School; George G Kihiczak, MD, Resident, Department of Dermatology, New Jersey Medical School, University of Medicine and Dentistry of New Jersey
Contributor Information and Disclosures

Updated: Oct 7, 2009

Introduction

Background

Melanoacanthoma is a term that Mishima and Pinkus1 introduced in 1960 to describe a pigmented, benign proliferation of both keratinocytes and dendritic melanocytes. Prior to this designation, Bloch2 described a similar lesion in 1927 that he called melanoepithelioma type I. Melanoepithelioma type II is an ordinary pigmented seborrheic keratosis. 

Oral melanoacanthoma is a rare, reactive, mucosal lesion, which, similar to cutaneous melanoacanthoma, is associated with hyperplasia of spinous keratinocytes and melanocytes.3 Its most common intraoral sites are the buccal mucosa, lip, palate, and gingiva.4,5,6,7 The average age at presentation is 28 years, and it occurs mainly in blacks, with a strong female predilection.8 Oral melanoacanthoma is unrelated to seborrheic keratosis. Oral melanoacanthoma is most often seen as an enlarging flat or slightly raised area of hyperpigmentation on the buccal mucosa of adult black women. Strong homatropine methylbromide reactivity has been described, limiting its utility in distinguishing oral melanoacanthoma from malignant melanoma.

Pathophysiology

Although melanoacanthoma can be found both on the skin and oral mucosa, the focus of this review is cutaneous melanoacanthoma. Although most authors consider cutaneous melanoacanthoma a benign tumor of melanocytes and keratinocytes, some have suggested it may be a reactive phenomenon induced by localized trauma.9

Frequency

United States

Cutaneous melanoacanthoma is generally regarded as rare. Melanoacanthoma was the primary diagnosis in 5 of 500,000 consecutive skin biopsy samples in one series from the United States.10

International

In their series of 189 consecutive seborrheic keratoses diagnosed among Spanish patients, Simon et al11 found that cutaneous melanoacanthoma represented 28% of all seborrheic keratoses.

Mortality/Morbidity

  • Cutaneous melanoacanthoma is a benign neoplasm. Simple excision is curative.
  • Morbidity with melanoacanthoma is uncommon. However, a melanoacanthoma that extends from the upper eyelid to beyond the lower eyelid can obstruct the patient's vision. The authors have observed this complication.
  • Melanoacanthomas may be as large as 10 cm in diameter and can therefore be unappealing to the patient.12

Race

Cutaneous melanoacanthoma is described more frequently white patients than in others. However, the lesion is rare in all ethnic groups.

Sex

Cutaneous melanoacanthoma develops in males and females with the same frequency.

Age

Cutaneous melanoacanthoma develops in middle-aged and elderly people. Melanoacanthoma has been described in patients aged 46-81 years, with an average age of 55-65 years.10,13

Clinical

History

  • Cutaneous melanoacanthomas are painless and slow growing. The slow but persistent growth and related cosmetic problems with melanoacanthomas may prompt an affected individual to consult a physician.
  • Patients are generally asymptomatic; however, trauma or manipulation of the melanoacanthoma may lead to bleeding or inflammation.
  • Patients may live with cutaneous melanoacanthoma for decades before they seek treatment.
  • Oral melanoacanthoma is rare, first noted with the sudden appearance and rapid growth of a brown-black macule.14 Gingival melanoacanthomas may be evident as solitary or multiple.15

Physical

  • Melanoacanthomas are most often solitary.
    • Multiple melanoacanthomas have been described.
    • In one case, a 40-year-old man had multiple, minute, discrete or confluent shiny papules limited to his left upper eyelid.16
  • Cutaneous melanoacanthomas are found mainly on the trunk or head, often on the lip or eyelid. They have also been observed on the penile shaft.13
  • Cutaneous melanoacanthomas may be hyperpigmented or verrucous and round or oval.
  • The lesion may be a papule, plaque, cutaneous horn, or nodule.
  • Lesional diameters range from a few millimeters to 10 cm.
  • The authors have observed a darkly pigmented cutaneous horn that extended from the left upper eyelid to below the lower eyelid in a 45-year-old man; the lesion had histologic findings consistent with melanoacanthoma (see Media File 1).
  • Melanoacanthomas can occur on the oral mucosa, but oral lesions are distinct from cutaneous melanoacanthomas. The oral melanotic macule is a small, well-circumscribed, brown-to-black macule that occurs on the lips and mucous membranes.8
Large cutaneous melanoacanthoma in a 45-year-old ...

Large cutaneous melanoacanthoma in a 45-year-old man that obstructs his vision.

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Large cutaneous melanoacanthoma in a 45-year-old ...

Large cutaneous melanoacanthoma in a 45-year-old man that obstructs his vision.


Causes

  • The cause of melanoacanthoma is unknown, but most instances appear to represent a benign neoplasm.
  • Irritation or trauma to the skin may cause some cutaneous melanoacanthomas, especially on the lips.
  • Trauma and irritation of the oral mucosa are believed to cause oral melanoacanthoma.

More on Cutaneous Melanoacanthoma

Overview: Cutaneous Melanoacanthoma
Differential Diagnoses & Workup: Cutaneous Melanoacanthoma
Treatment & Medication: Cutaneous Melanoacanthoma
Follow-up: Cutaneous Melanoacanthoma
Multimedia: Cutaneous Melanoacanthoma
References
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References

  1. Mishima Y, Pinkus H. Benign mixed tumor of melanocytes and malpighian cells. Melanoacanthoma: Its relationship to Bloch's benign non-nevoid melanoepithelioma. Arch Dermatol. Apr 1960;81:539-50. [Medline].

  2. Bloch B. Uber benigne, nicht naevoide Melanoepitheliome der Haut nebst Bemerkungen uber das Wesen und die Genese der Dendritenzellen. Arch Dermatol Syph (Berlin). 1927;153:20-40.

  3. Fornatora ML, Reich RF, Haber S, Solomon F, Freedman PD. Oral melanoacanthoma: a report of 10 cases, review of the literature, and immunohistochemical analysis for HMB-45 reactivity. Am J Dermatopathol. Feb 2003;25(1):12-5. [Medline].

  4. Flaitz CM. Oral melanoacanthoma of the attached gingiva. Am J Dent. Jun 2000;13(3):162. [Medline].

  5. Frey VM, Lambert WC, Seldin RD, Schneider LC, Mesa ML. Intraoral melanoacanthoma. J Surg Oncol. Oct 1984;27(2):93-6. [Medline].

  6. Matsuoka LY, Glasser S, Barsky S. Melanoacanthoma of the lip. Arch Dermatol. Sep 1979;115(9):1116-7. [Medline].

  7. Sexton FM, Maize JC. Melanotic macules and melanoacanthomas of the lip. A comparative study with census of the basal melanocyte population. Am J Dermatopathol. Oct 1987;9(5):438-44. [Medline].

  8. Carlos-Bregni R, Contreras E, Netto AC, et al. Oral melanoacanthoma and oral melanotic macule: a report of 8 cases, review of the literature, and immunohistochemical analysis. Med Oral Patol Oral Cir Bucal. Sep 1 2007;12(5):E374-9. [Medline].

  9. Matsuoka LY, Barsky S, Glasser S. Melanoacanthoma of the lip. Arch Dermatol. May 1982;118(5):290. [Medline].

  10. Prince C, Mehregan AH, Hashimoto K, Plotnick H. Large melanoacanthomas: a report of five cases. J Cutan Pathol. Aug 1984;11(4):309-17. [Medline].

  11. Simon P, Requena L, Sanchez Yus E. How rare is melanoacanthoma?. Arch Dermatol. Apr 1991;127(4):583-4. [Medline].

  12. Kihiczak GG, Centurion SA, Schwartz RA, Lambert WC. Giant cutaneous melanoacanthoma. Int J Dermatol. Dec 2004;43(12):936-7. [Medline].

  13. Vion B, Merot Y. Melanoacanthoma of the penis shaft. Report of a case. Dermatologica. 1989;179(2):87-9. [Medline].

  14. Lakshminarayanan V, Ranganathan K. Oral melanoacanthoma: a case report and review of the literature. J Med Case Reports. Jan 13 2009;3:11. [Medline].

  15. Brooks JK, Sindler AJ, Papadimitriou JC, Francis LA, Scheper MA. Multifocal melanoacanthoma of the gingiva and hard palate. J Periodontol. Mar 2009;80(3):527-32. [Medline].

  16. Spott DA, Heaton CL, Wood MG. Melanoacanthoma of the eyelid. Arch Dermatol. Jun 1972;105(6):898-9. [Medline].

  17. Lee JY, Lin MH. Pigmented malignant hidroacanthoma simplex mimicking irritated seborrheic keratosis. J Cutan Pathol. Oct 2006;33(10):705-8. [Medline].

  18. Schlappner OL, Rowden G, Philips TM, Rahim Z. Melanoacanthoma. Ultrastructural and immunological studies. J Cutan Pathol. Jun 1978;5(3):127-41. [Medline].

  19. Lambert MW, Lambert WC, Schwartz RA, et al. Colonization of nonmelanocytic cutaneous lesions by dendritic melanocytic cells: a simulant of acral-lentiginous (palmar-plantar-subungual-mucosal) melanoma. J Surg Oncol. Jan 1985;28(1):12-8. [Medline].

  20. Lambert WC, Lambert MW, Mesa ML, et al. Melanoacanthoma and related disorders. Simulants of acral-lentiginous (P-P-S-M) melanoma. Int J Dermatol. Oct 1987;26(8):508-10. [Medline].

  21. Andrews BT, Trask DK. Oral melanoacanthoma: a case report, a review of the literature, and a new treatment option. Ann Otol Rhinol Laryngol. Sep 2005;114(9):677-80. [Medline].

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Further Reading

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Keywords

cutaneous melanoacanthoma, melanoacanthoma, benign mixed tumor of melanocytes and malpighian cells, seborrheic keratoses, melanoepithelioma type I, melanoepithelioma type II, keratinocytes, dendritic melanocytes, MA, oral melanoacanthoma

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Contributor Information and Disclosures

Author

Robert A Schwartz, MD, MPH, Professor and Head, Dermatology, Professor of Pathology, Pediatrics, Medicine, and Preventive Medicine and Community Health, UMDNJ-New Jersey Medical School
Robert A Schwartz, MD, MPH is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American College of Physicians, and Sigma Xi
Disclosure: Nothing to disclose.

Coauthor(s)

W Clark Lambert, MD, PhD, Professor and Head, Dermatopathology, Departments of Pathology and Dermatology, UMDNJ-New Jersey Medical School
W Clark Lambert, MD, PhD is a member of the following medical societies: American Academy of Dermatology, American College of Physicians, American Dermatological Association, American Society of Dermatopathology, International Academy of Pathology, Medical Society of New Jersey, Sigma Xi, and Society for Investigative Dermatology
Disclosure: Nothing to disclose.

George G Kihiczak, MD, Resident, Department of Dermatology, New Jersey Medical School, University of Medicine and Dentistry of New Jersey
George G Kihiczak, MD is a member of the following medical societies: American Academy of Dermatology, American Medical Association, and Sigma Xi
Disclosure: Nothing to disclose.

Medical Editor

Michelle Pelle, MD, Clinical Assistant Professor, Division of Dermatology, Department of Medicine, University of California at San Diego
Michelle Pelle, MD is a member of the following medical societies: American Academy of Dermatology, California Medical Association, Medical Dermatology Society, and Pennsylvania Medical Society
Disclosure: Nothing to disclose.

Pharmacy Editor

David F Butler, MD, Professor of Dermatology, Texas A&M University College of Medicine; Chair, Department of Dermatology, Director, Dermatology Residency Training Program, Scott and White Clinic, Northside Clinic
David F Butler, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American Medical Association, American Society for Dermatologic Surgery, American Society for MOHS Surgery, Association of Military Dermatologists, and Phi Beta Kappa
Disclosure: Nothing to disclose.

Managing Editor

Christen M Mowad, MD, Associate Professor, Department of Dermatology, Geisinger Medical Center
Christen M Mowad, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, and Phi Beta Kappa
Disclosure: Nothing to disclose.

CME Editor

Catherine Quirk, MD, Clinical Assistant Professor, Department of Dermatology, Brown University
Catherine Quirk, MD is a member of the following medical societies: Alpha Omega Alpha and American Academy of Dermatology
Disclosure: Nothing to disclose.

Chief Editor

Dirk M Elston, MD, Director, Department of Dermatology, Geisinger Medical Center
Dirk M Elston, MD is a member of the following medical societies: American Academy of Dermatology
Disclosure: Nothing to disclose.

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