Section : Conference Notes

Solar Lentigo (For Professionals)

Solar Lentigo (For Professionals)


  • Occurs mostly in Caucasians phototypes1,2 and 3
  • Affects worldwide 90% of humans over 70 of age. This amounts today to 600 million aged 65 and over, this will be 2 billion individuals in 2050

Psychological impact

  • it is a marker of aging and is visible as it occurs mostly on face and hands
  • indeed 20% of patients in the US seek treatment when aged between 45 and 55

Differential Diagnosis

  • (Focused): PIH, melasma (chloasma), Seborrheic (Seborrhoeic) Keratosis, reticulated black solar lentigo=ink spot lentigo (melanin unevenly distributed), UVA and PUVA lentigo, sunburn spots (on back, a marker of melanoma presence), ephelides (freckles) (MCR-1 Gene mutation) (not related to sun expression), pigmented seb K, pigmented AK, extensive pigmented AK, Hutchinson’s Melanotic Freckle (HMF) (Dubreuil’s Melanosis) (Lentigo Maligna).
  • To be complete: juvenile lentigo (lentigo simplex), freckles (epehlides), ink spot lentigo, PUVA-induced lentigenes, Tanning-Bed lentigenes, Seborrheic (Seborroeic) Keratosis, Pigmented actinic keratoses, Large Cell Acanthoma, Junctional Nevomelanocytic nevus, Flat reticular and pigmented seborrheic keratosis, pigmented and pigmented-spreading actinic keratosis, sunburn spot.


  • Elongation of reted ridges with bud-like extensions of the epidermis (without cellular atypia) into the dermis except (on the face).


  • progressive stages: increase of melanocytes, elongation of the rete ridges and increased pigment deposition. Increased melanin synthesis.
  • Implicated mediators
  1. endothelin 1 and receptor
  2. Genes Involved (Keratinocytes and Melanocytes):

-SCF (stem cell factor)


-KGF (Keratinocyte growth factor)

-KGF receptor

-HGF (Hepatocyte Growth Factor)

-Il-1 alpha

-FGFR3 (hyperpigmentation)

-PIK 3CA (hyperpigmentation)

  • Another observation is that granulated cells expressing FXIIIa are also present in the dermal part of SL (dendrocyte marker). These melanin-laden cells are filled with larger than normal melanosomes (it is not known how the epidermal to dermal trnsfer of melanin takes place).

Treatments in general

  • hypomelanoses: cryotherapy
  • hypermelanoses: cryotherapy, peeling, dermabrasion, laser, hydroquinone and other depigmenting agents, retinoic acid


Dr Christophe HSU – dermatologist. Geneva, Switzerland

Bibliography: Ortonne JP, Aging and Photoaging – 22nd World Congress of Dermatology (WCD) – Seoul, South Korea

Category : actinic lentigo - Modifie le 05.25.2011Category : lentigo solaire - Modifie le 05.25.2011Category : solar lentigo - Modifie le 05.25.2011