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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/01/04 09:45:33」(JST)

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Histology slide of a solar lentigo

Liver spots (also known as age spot, solar lentigo,^[1] "Lentigo senilis",^[1]^:686 "Old age spot,"^[2] "Senile freckle"^[2]) are blemishes on the skin associated with aging and exposure to ultraviolet radiation from the sun. They range in color from light brown to red or black and are located in areas most often exposed to the sun, particularly the hands, face, shoulders, arms and forehead, and the scalp if bald.

The spots derive their name from the fact that they were once incorrectly believed to be caused by liver problems, but they are physiologically unrelated to the liver, save for a similar color.^[3] From the age of 40 onward the skin is less able to regenerate from sun exposure, and liver spots are very common in this age group, particularly in those who spend time in the sun.^{[citation needed]}

In the overwhelming majority of cases, liver spots pose no threat and require no treatment, though they occasionally have been known to obscure the detection of skin cancer. However, despite being a benign condition, liver spots are sometimes considered unsightly and some people choose to have them removed. This can be done by electrosurgery, laser treatment, cryotherapy, or the use of tretinoin or alpha hydroxy acids.^[4]

Causes

Differently from the melanotic nevi and the verrucous nevi on the skin, age spots change with time in color and in shape. Misrepair-accumulation aging theory ^[5]^[6] proposes a hypothesis on the development of age spots.^[7] Firstly, the development of a flat spot is a result of accumulation of aged basal cells. When the skin is aged, some aged cells that contain lipofuscin bodies cannot be removed. An aged cell will affect the functionality of the local tissue and promote the aging of its neighbor cells. By a feedback loop, more and more neighbor cells become aged and lipofuscin-containing. They aggregate and form a spot with irregular shape. Secondly, protruding of a flat spot is a result of death of aged cells in the spot and release of lipofuscin bodies. Isolation of the un-digestible lipofuscin bodies in a fibrotic capsule is essential for maintaining the structural integrity of the tissue. Successive encapsulation of dead cells and lipofuscin bodies results in the growth of a spot in three dimensions. The dense lipofuscin bodies in the capsule make a protruding spot soft and dark in color.

References

^ ^a ^b James, William D.; Berger, Timothy G.; et al. (2006). Andrews' Diseases of the Skin: Clinical Dermatology. Saunders Elsevier. ISBN 0-7216-2921-0.
^ ^a ^b Rapini, Ronald P.; Bolognia, Jean L.; Jorizzo, Joseph L. (2007). Dermatology: 2-Volume Set. St. Louis: Mosby. pp. 1716–17. ISBN 1-4160-2999-0.
^ Karen J. Carlson, Stephanie A. Eisenstat, Terra Diane Ziporyn, The new Harvard guide to women's health, Harvard University Press, 2004, p.337.
^ "Overview about liver spots/age spots". Beauty Natural Skin. Retrieved 3 July 2015.
^ Wang, Jicun; Michelitsch, Thomas; Wunderlin, Arne; Mahadeva, Ravi (2009). "Aging as a consequence of Misrepair –a novel theory of aging" 0904: 9. arXiv:0904.0575. Bibcode:arXiv:0904.0575.
^ Wang-Michelitsch, Jicun; Michelitsch, Thomas (2015). "Aging as a process of accumulation of Misrepairs" 1503: 13. arXiv:1503.07163. Bibcode:arXiv:1503.07163.
^ Wang-Michelitsch, Jicun; Michelitsch, Thomas (2015). "Development of age spots as a result of accumulation of aged cells in aged skin" 1505: 9. arXiv:1505.07012. Bibcode:arXiv:1505.07012.

External links

Mayo Clinic: Age spots (liver spots)
Prime Health Channel: Solar Lentigo(Liver Spots)

UpToDate Contents

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1. 色素細胞性母斑（ほくろ）以外の良性色素性皮膚病変 benign pigmented skin lesions other than melanocytic nevi moles
2. 皮膚の良性病変の概要 overview of benign lesions of the skin
3. 悪性黒子：臨床症状、診断、およびマネージメント lentigo maligna clinical manifestations diagnosis and management
4. モース手術 mohs surgery
5. 黒色腫の病理学的特徴 pathologic characteristics of melanoma

English Journal

Paracrine cytokine mechanisms underlying the hyperpigmentation of seborrheic keratosis in covered skin areas.

Takenaka Y1, Hoshino Y, Nakajima H, Hayashi N, Kawashima M, Imokawa G.
The Journal of dermatology.J Dermatol.2013 Jul;40(7):533-42. doi: 10.1111/1346-8138.12178. Epub 2013 May 10.
We previously reported that increased expression of the endothelin (EDN)1/EDNB receptor (EDNBR) as well as the stem cell factor (SCF)/SCF receptor (c-KIT) linkages is mainly responsible for the activation of melanocytes in the epidermal hyperpigmentation of ultraviolet (UV)-B melanosis and lentigo s
PMID 23662587

Extrinsic aging: UV-mediated skin carcinogenesis.

Tsatsou F1, Trakatelli M, Patsatsi A, Kalokasidis K, Sotiriadis D.
Dermato-endocrinology.Dermatoendocrinol.2012 Jul 1;4(3):285-97. doi: 10.4161/derm.22519.
Age-associated skin lesions linked to UV radiation (UVR) include actinic keratosis, non-melanoma skin cancer-such as basal cell carcinoma and squamous cell carcinoma-lentigo senilis and lentigo maligna. Their incidence is increasing worldwide, mainly due to exaggerated UV exposure and to an aging po
PMID 23467430

Withania somnifera extract attenuates stem cell factor-stimulated pigmentation in human epidermal equivalents through interruption of ERK phosphorylation within melanocytes.

Nakajima H1, Fukazawa K, Wakabayashi Y, Wakamatsu K, Imokawa G.
Journal of natural medicines.J Nat Med.2012 Jul;66(3):435-46. doi: 10.1007/s11418-011-0604-0. Epub 2011 Nov 16.
We previously demonstrated that mitogen-activated protein kinase (MAPK) signaling, including microphthalmia-associated transcription factor (MITF) and cAMP response element-binding protein (CREB) phosphorylation, is a major pathway involved in up-regulating melanogenesis within human melanocytes in
PMID 22086674

Japanese Journal

Whitening efficacy of plant extracts including orchid extracts on Japanese female skin with melasma and lentigo senilis

Journal of dermatology 37(6), 522-530, 2010-06-01
NAID 10026546546

松樹皮抽出物(フラバンジェノール)のシミに対する臨床効果と作用機序の検討 (飲んで皮膚に効く! 化粧品・医薬品・食品の開発)

コスメティックステージ 3(2), 36-40, 2008-12
NAID 40016425312

Neuroendocrine Functions of Melanocytes : Beyond the Skin-Deep Melanin Maker

THE TOHOKU JOURNAL OF EXPERIMENTAL MEDICINE 211(3), 201-221, 2007-03-01
NAID 10018873930

Related Pictures

★リンクテーブル★

リンク元

「老人性色素斑」

Liver spot
	A 10 mm liver spot (solar lentigo) on the forearm of a 66-year-old woman
Classification and external resources
Specialty	dermatology
ICD-10	L81.4
ICD-9-CM	709.09
DiseasesDB	34327
MedlinePlus	001141
eMedicine	derm/221
MeSH	D007911

　　[★]

英: senile pigment freckle
ラ: lentigo senilis
同: 老人斑、老人性黒子

[Andrews-1] James, William D.; Berger, Timothy G.; et al. (2006). Andrews' Diseases of the Skin: Clinical Dermatology. Saunders Elsevier. ISBN 0-7216-2921-0.

[Bolognia-2] Rapini, Ronald P.; Bolognia, Jean L.; Jorizzo, Joseph L. (2007). Dermatology: 2-Volume Set. St. Louis: Mosby. pp. 1716–17. ISBN 1-4160-2999-0.

[3] Karen J. Carlson, Stephanie A. Eisenstat, Terra Diane Ziporyn, The new Harvard guide to women's health, Harvard University Press, 2004, p.337.

[4] "Overview about liver spots/age spots". Beauty Natural Skin. Retrieved 3 July 2015.

[5] Wang, Jicun; Michelitsch, Thomas; Wunderlin, Arne; Mahadeva, Ravi (2009). "Aging as a consequence of Misrepair –a novel theory of aging" 0904: 9. arXiv:0904.0575. Bibcode:arXiv:0904.0575.

[6] Wang-Michelitsch, Jicun; Michelitsch, Thomas (2015). "Aging as a process of accumulation of Misrepairs" 1503: 13. arXiv:1503.07163. Bibcode:arXiv:1503.07163.

[7] Wang-Michelitsch, Jicun; Michelitsch, Thomas (2015). "Development of age spots as a result of accumulation of aged cells in aged skin" 1505: 9. arXiv:1505.07012. Bibcode:arXiv:1505.07012.

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案内

lentigo senilis