Penis & scrotum


Melanosis and lentiginosis

Last author update: 1 February 2010
Last staff update: 29 October 2021

Copyright: 2002-2023,, Inc.

PubMed Search: (Melanosis OR lentiginosis) penis

Alcides Chaux, M.D.
Antonio L. Cubilla, M.D.
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Cite this page: Chaux A, Cubilla AL. Melanosis and lentiginosis. website. Accessed May 29th, 2023.
Definition / general
Clinical features
  • Benign, although associated with melanoma

Penile melanosis:
  • Large, often single, flat and pigmented macule with irregular borders
  • Pigmentation may be associated with Laugier-Hunziker syndrome (Int J Dermatol 2004;43:571)

Penile lentiginosis:
  • Penile lentigines are 0.2 - 2 cm, oval to irregular lesions with uniform or variegated pigmentation
  • Areas of depigmentation are characteristic
  • Lesions are scattered on shaft or glans
  • Clinically may resemble an atypical melanocytic lesion
  • May be associated with Cowden disease (J Cutan Med Surg 2001;5:228), Bannayan-Riley-Ruvalcaba syndrome (J Am Acad Dermatol 2005;53:639)
Clinical images

AFIP images


Microscopic (histologic) description
Penile melanosis:
  • Melanocytic hyperplasia, hyperpigmentation of basal epithelium and otherwise normal epithelium

Penile lentiginosis:
  • Elongation of rete ridges with basal layer hyperpigmentation, slight melanocytic hyperplasia, epithelial hyperplasia and stromal melanophages, no atypia (J Am Acad Dermatol 1990;22:453)
  • In hyperpigmented areas, there are increased number of melanocytes along the basal layer
  • Lymphocytes, which are found in close apposition, destroy melanocytes and surrounding keratinocytes lack pigmentation (Pigment Cell Res 1992;5:404)
Microscopic (histologic) images

AFIP images


Differential diagnosis
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