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Lentigo

Updated : February 20, 2024





Background

Lentigo maligna (LM), a form of melanoma, typically manifests as an uneven brown macule on skin that has been exposed to the sun for an extended period of time, especially the head & neck in older people. Hutchinson first identified it in 1890, calling it “Hutchinson’s melanotic freckle.” Due to its sluggish growth, LM was largely believed to be premalignant, benign, or infectious in origin throughout much of the early twentieth century.

Terms like “infective senile freckles,” “junctional nevus,” & “circumscribed premalignant melanosis” were used to describe the condition. It wasn’t until the research of Silvers, Ackerman, & colleagues in the late 1970s and early 1980s that LM was widely acknowledged as cancerous. Melanoma in situ (MIS) on permanently sun-damaged skin is the current definition of LM.

LM is therefore restricted to the epidermis by definition. LMM (Lentigo maligna melanoma) is the word used if the lesion invades. In this article, we go over the essential features of LM/LMM and talk about the specific difficulties with this condition’s diagnosis and care.

 

Epidemiology

With 4 – 15 percent of all melanoma & 10 – 26 percent of head and neck melanoma, LM/LMM is the 3rd most prevalent subgroup of melanomas (after SSM & NM). The average age of diagnosis for this subtype of melanoma is 66 to 72 years, as opposed to 45–57 years for other subtypes. Women are significantly older at diagnosis and are afflicted more frequently than males (1.7 to 1).

According to data from Olmstead Province, Minnesota, the prevalence of LM/LMM increased over the previous three decades, ranging from 2.2 deaths per 1000 person-years in 1970 & 1989 to 13.7 instances per 100,000 person-years in 2004 & 2007. Incidence levels increased similarly in the Netherlands.

According to Californian data, the frequency of the disease increased by 52% among younger persons aged 45 – 64 in 1990 and 2000. Whether these figures reflect actual increases in prevalence or better diagnosis is questionable. The faster increase in MIS incidence relative to invasive melanomas shows that at least some identification bias is at play.

 

Anatomy

Pathophysiology

Melanoma is one of the cancers with the greatest mutational burdens, and LM/LMM has an unusually high alteration rate as a result of repeated Ultraviolet rays exposure. UVR results in oxidative stress and the characteristic C>T & CC>TT alterations, which in turn change the NRAS, BRAF, & KIT genes that are implicated in the PI3K & MAPK cascades.

The change into a malignant cancer is then brought on by secondary alterations in CCND1, CDKN2A, and p53. LM/LMM is more probable to have KIT mutations than other subgroups of melanomas, which are more likely to have BRAF mutants. Additionally, pathogenic MITF, CCND1, NRAS, & p53 mutations exist.

 

Etiology

UV radiation, especially cumulative lifelong UVR radiation, is the main predisposing factor for LM/LMM. In contrast to nodular melanomas (NM) & superficially spreading melanomas (SSM), which are linked to severe irregular UVR radiation, investigations have shown that LM/LMM is substantially connected with persistent UVR visibility. According to an Australian study, LM risk increases with time spent in Australia, the number of hours spent in the sun, the number of actinic injuries, and a history of nonmelanoma skin carcinoma.

In addition, LM/LMM is more likely to affect the face, which is a location of persistent sun exposure, whereas SSM & NM are more likely to affect men’s trunks and women’s legs, which are both more frequently covered. Last but not least, LM tends to affect elderly patients in comparison to SSM & NM, possibly because older people have had more lifetime sunlight exposure.

X-ray exposure, estrogen/progesterone, & non-permanent hair colors have all been proposed as potential factors in addition to UV radiation. In addition, LM is more prone to develop in people with UV sensitivity-related genetic disorders such as Werner syndrome, xeroderma pigmentosum, oculocutaneous albinism, & porphyria cutanea tarda. No correlations with drinking or smoking have been shown.

 

Genetics

Prognostic Factors

Excellent outlook for LM/LMM. There were no disease-related fatalities for LM and just one for LMM in a study of 270 individuals with LM/LMM who underwent total excision. The disease-specific rate of survival at five and ten years was 100 & 97.1%, accordingly. So, LM by itself does not shorten life expectancy.

After adjusting for Breslow depth, the prognosis is identical for all other melanoma once the tumor becomes metastatic, however, it can be fairly bad if the illness spreads (five-year survival rate is 9 to 27%). Given the potentially huge surface area on the head and neck that may be implicated and the requirement for extensive surgical removal & rebuilding, morbidity for patients can be severe even though mortality is minimal.

 

Clinical History

Clinical History

Lentigines can have a wide range of early appearances depending on the following factors:

  • Race
  • Exposure history
  • Genetic propensity
  • Depending on the type of lentigo, additional considerations

 

Physical Examination

Physical examination

Depending on the lesion’s type, lentigines differ in both physical characteristics and their physical shape.

Lentigo simplex

The most typical type of lentigo is called lentigo simplex (also known as simple lentigo or juvenile lentigo). Neither exposure to the sun nor systemic illness are causes of lentigo simplex. Clinically, the lesions are 3–15 mm in diameter, round or oval, asymptomatic macules. They might have smooth or angular borders. The color of the pigmentation, which ranges from brown to black, is uniformly spread. The lesions can appear anywhere on the skin or mucous membranes and are often harmless. The lesions often grow over time, but they can also be present from birth or occur earlier. An imatinib mesylate-treated patient with familial gastrointestinal stromal tumor syndrome saw a decrease in the number of multiple dysplastic nevi and lentigines. It is not entirely clear how imatinib affects pigmentation.

Solar lentigo

The most frequent benign sun-induced lesion that develops in sun-exposed areas is solar lentigo, which includes senile lentigo, actinic lentigo, sunspots, and liver spots. The face, arms, hands, & upper half of the trunk are the areas of the body where solar lentigo most frequently manifests. The spots have a smaller beginning diameter than 5 mm. Lesions often have a flat and depressed surface that may also include subtle wrinkling. The lesions are typically brown, although they can also be black, yellow-tan, or other colors. Lesions that are older tend to be dark brown or brownish black. Lentigines on the sun get bigger and more numerous with time. Huge patches are eventually formed when numerous lesions combine. Despite the fact that people in their 30s and 50s are most likely to develop these lesions, younger people are already exhibiting them due to increased sun exposure and the use of artificial UV light sources. Although they are frequently referred to as liver spots, they are not a symptom of a systemic illness.

Ink-spot lentigo

A wiry or beaded, noticeably uneven outline helps to recognize ink-spot lentigo (also known as reticulated black solar lentigo), a condition that affects persons with Celtic ancestry. Most benign lesions resemble an ink stain and have a reticulated pattern. Similar to solar lentigo, the distribution is restricted to skin-exposed regions of the body; however, unlike solar lentigines, individuals typically only have one ink-spot lentigo. These lesions can also be recognized from the darkly pigmented PUVA lentigo by the many central and peripheral skip areas and more reticulated and beaded patterns. Due to their dark hue, irregular border, and rarity, ink-spot lentigines may at first be mistaken for melanoma; however, further examination, which may involve biopsy, shows the distinctive characteristics of these benign tumors.

Radiation lentigo

While radiation lentigo mimics UV-induced lentigo, it also frequently consists of other histopathologic indicators of long-term epidermal radiation damage, such as keratosis, telangiectasias, subcutaneous fibrosis, and epidermal atrophy. A radiation lentigo is thought to be a sign of previous skin exposure to a high dose of ionizing radiation (e.g., the Chernobyl nuclear accident exposure). There is no evidence that these lesions develop after localized, fractionated radiation treatment. Lentigines caused by radiation can last for up to 4 months after the original exposure. The lesions’ propensity for malignancy is uncertain, however, ionizing rays have never been confirmed to cause melanoma.

PUVA lentigo

A persistent, light brown macule known as PUVA lentigo appears six months or more after the beginning of PUVA treatment for psoriasis. Although the lesions resemble solar lentigines, they frequently have more erratic borders and may look like ephelides. Lesions are closely connected with higher cumulative doses of PUVA, and they can occur at any treatment location. The upper portion of the chest and back, as well as the glans, penis, groin, buttocks, & penile shaft, are the most frequently affected locations. The gluteal cleft, axillae, palms, and soles are unharmed. The lesions range in size from 3 to 8 mm. However, stellate lesions can be up to 3 cm in diameter. After the therapy is stopped, the lentigines may continue for three to six months. Stellate lesions, on the other hand, might last for more than two years.

Oral & labial melanotic macules

Labial and oral melanotic macules are comparable. The lower lip’s vermilion is usually often the site of labial lesions, which can be brown, blue, or blue-black in hue. Variegated pigmentation might happen occasionally. The lesions are often symmetric, asymptomatic, and isolated. The gingiva, palate, buccal mucosa, & tongue can all develop oral lesions.

Vulvar & penile lentigo

The benign lesions known as penile and vulvar lentigo resemble labial melanotic macules. The glans penis, corona sulcus, corona, & penile shaft in men are the most frequently affected areas. The lesions have uneven borders & skip sections, and their colors range from tan to brown to dark brown. The diameter of a single lesion might reach 15 mm. When it comes to women, the lesions show up as a mottled, pigmented patch with skip patches anyplace on the vaginal mucosa. The diameter might range from 5 to 15 mm or more. After labor, episiotomy scars may also develop lesions. In the LAMB syndrome, lentigos affecting the external genitalia have also been documented.

Agminated lentiginosis

Agminated (segmental, unilateral, or partial unilateral) lentiginosis is distinguished by an abundance of lentigines that are contained inside a body segment and have a clear midline demarcation. One or more dermatomes frequently match the distribution. Less frequently, the lesions might be spread in midline clusters, unilaterally, bilaterally, or in a checkerboard pattern. The condition often first manifests in early childhood, though lentigines can also be seen before birth. Numerous diseases have been linked to these lesions. On healthy background skin, the lesions show up clinically as confined, tan, or dark brown macules.

Lentigines profuse

Lentigines profuse (also known as generalized lentigines) are characterized by a large number of lentigines with no signs of related abnormalities or causative factors. Although it has a vast prevalence, lentigines profusa has a clinical presentation similar to ephelides. The trunk, extremities, palms, & genitalia are frequently involved. Conjunctiva and other mucosal surfaces may also be impacted, while the buccal mucosa may be unaffected. The macules range in size from 1 mm to 2 cm. The macules are a variety of colors, from dark brown to black.

Xeroderma pigmentosum

The autosomal-recessive disorder known as Xeroderma pigmentosum (XP) is characterized by defects that result from cells’ inability to repair DNA damage brought on by exposure to UV radiation and certain chemicals. Clinically, patients exhibit increasing pigmentary alterations and skin shrinkage. Neoplastic skin alterations then develop, frequently in youth; basal cell and squamous cell carcinomas are the most prevalent malignancies. There may also be an increase in malignancies like melanoma. The head, neck, and face, in particular, are sun-exposed locations where all of these neoplastic alterations develop.

LEOPARD syndrome

The LEOPARD syndrome, also known as multiple lentigines syndrome, is a complex dysmorphogenetic disorder that is passed on as an autosomal-dominant trait with variable penetrance. It is characterized by lentigines, electrocardiographic conduction defects, ocular hypertelorism, pulmonary stenosis, abnormal genitalia, retardation of growth, and deafness. There may be evidence of a PTPN11 gene mutation. Since most patients only meet three to five of the criteria, making the diagnosis can take time and effort. Although they are not necessary for the diagnosis of LEOPARD syndrome, lentigos are the most typical hallmark of the illness.

Peutz-Jeghers syndrome

A highly penetrant autosomal-dominant disorder known as Peutz-Jeghers syndrome is characterized by gastrointestinal polyps and colored macules. The jejunum is frequently affected by benign hamartomas known as polyps, which can affect the entire gut. Recurrent perirectal bleeding and stomach pain are brought on by these polyps. Intussusception or bleeding that presents as a blockage, abdominal discomfort, rectal prolapse, nausea, and currant spongy stools is frequently present when patients are first examined.

Inherited patterned lentiginosis

Blacks may get hereditary patterns of lentiginosis. On the cheeks and lips, this type is distinguished by hyperpigmented macules. Additional lesions can occasionally be found on the palmoplantar surfaces, knees, elbows, and buttocks. The oral mucosa does not have lesions, and they do not appear to increase the risk of cancer or affect any organs. The inheritance is autosomal dominant. Families with red-haired ancestors and light-skinned African Americans, some of whom have a mixed history with American Indians, are particularly impacted.

Nevus spilus

The nevus spilus is a rare neoplasm with a small chance of turning into melanomas. It is both lentigo and melanocytic. Multiple pigmented papules or macules inside a naturally occurring or acquired pigmented area serve as clear indicators.

 

Age group

Associated comorbidity

Associated activity

Acuity of presentation

Differential Diagnoses

Differential Diagnoses

Seborrheic Keratosis

Porokeratosis

Freckles/Ephelides

Actinic Keratosis

 

Laboratory Studies

Imaging Studies

Procedures

Histologic Findings

Staging

Treatment Paradigm

The preferred course of treatment is surgical resection. The conventional 0.5 cm operative margins for MIS have been proven in numerous studies to be insufficient for LM, with about half of the tumors requiring bigger margins for recurrence & clearance rates around 8 – 20%. Numerous single-center research has called for greater margins of up to 1.0 cm or over, and the National Comprehensive Cancer Network amended its guidelines in 2014 to propose 0.5–1.0 cm margins for MIS.

Recent research by Zitelli & Brodland, who performed Mohs micrographic therapy (MMS) on more than 1500 instances of LM, showed that 1.2 cm margins were necessary to obtain a 97 percent compliance rate. According to expert panels, wide local excision (WLE) is still the gold standard of care for surgical procedures. The MMS, though, maybe superior, according to an increasing number of studies. Several universities have shown the risk of recurrence of 1.8 – 1.9% using MMS & 5.8 to 5.9% utilizing WLE for LM.

Incidence rates with MMS can be as minimal as 0.3 – 0.5% in the hands of a skilled physician using immunohistochemistry. Topical imiquimod 5 percent cream may be a good option for people who don’t want surgery or aren’t good surgical patients, though the evidence is conflicting. For imiquimod, the clinical & histologic remission rates vary from 46 – 78% & 37 – 76%, accordingly. Another viable non-surgical approach is radiation treatment.

Radiation delivery techniques and types can vary, although Grenz rays, or fractionated superficial radiation, are most frequently used. The reported range of recurrence rates is 5 – 14%. Azelaic acid, cryotherapy, laser ablation, 5-fluorouracil cream, & chemical peels are only a few of the additional non-surgical methods that have been described with varying degrees of efficacy. However, the available data is insufficient & inconsistent to make any firm conclusions.

 

by Stage

by Modality

Chemotherapy

Radiation Therapy

Surgical Interventions

Hormone Therapy

Immunotherapy

Hyperthermia

Photodynamic Therapy

Stem Cell Transplant

Targeted Therapy

Palliative Care

Medication

 

mequinol/gluconolactone/ lactobionic acid/ arbutin 

solar:

Apply topical solution containing mequinol (20 mg/1mL) and Tretinoin (0.1 mg/1mL) to the affected region of skin twice a day (morning and evening), a minimum of 8 hours apart



 
 

Media Gallary

References

https://www.ncbi.nlm.nih.gov/books/NBK482163/

https://emedicine.medscape.com/article/1068503-differential

 

Lentigo

Updated : February 20, 2024




Lentigo maligna (LM), a form of melanoma, typically manifests as an uneven brown macule on skin that has been exposed to the sun for an extended period of time, especially the head & neck in older people. Hutchinson first identified it in 1890, calling it “Hutchinson’s melanotic freckle.” Due to its sluggish growth, LM was largely believed to be premalignant, benign, or infectious in origin throughout much of the early twentieth century.

Terms like “infective senile freckles,” “junctional nevus,” & “circumscribed premalignant melanosis” were used to describe the condition. It wasn’t until the research of Silvers, Ackerman, & colleagues in the late 1970s and early 1980s that LM was widely acknowledged as cancerous. Melanoma in situ (MIS) on permanently sun-damaged skin is the current definition of LM.

LM is therefore restricted to the epidermis by definition. LMM (Lentigo maligna melanoma) is the word used if the lesion invades. In this article, we go over the essential features of LM/LMM and talk about the specific difficulties with this condition’s diagnosis and care.

 

With 4 – 15 percent of all melanoma & 10 – 26 percent of head and neck melanoma, LM/LMM is the 3rd most prevalent subgroup of melanomas (after SSM & NM). The average age of diagnosis for this subtype of melanoma is 66 to 72 years, as opposed to 45–57 years for other subtypes. Women are significantly older at diagnosis and are afflicted more frequently than males (1.7 to 1).

According to data from Olmstead Province, Minnesota, the prevalence of LM/LMM increased over the previous three decades, ranging from 2.2 deaths per 1000 person-years in 1970 & 1989 to 13.7 instances per 100,000 person-years in 2004 & 2007. Incidence levels increased similarly in the Netherlands.

According to Californian data, the frequency of the disease increased by 52% among younger persons aged 45 – 64 in 1990 and 2000. Whether these figures reflect actual increases in prevalence or better diagnosis is questionable. The faster increase in MIS incidence relative to invasive melanomas shows that at least some identification bias is at play.

 

Melanoma is one of the cancers with the greatest mutational burdens, and LM/LMM has an unusually high alteration rate as a result of repeated Ultraviolet rays exposure. UVR results in oxidative stress and the characteristic C>T & CC>TT alterations, which in turn change the NRAS, BRAF, & KIT genes that are implicated in the PI3K & MAPK cascades.

The change into a malignant cancer is then brought on by secondary alterations in CCND1, CDKN2A, and p53. LM/LMM is more probable to have KIT mutations than other subgroups of melanomas, which are more likely to have BRAF mutants. Additionally, pathogenic MITF, CCND1, NRAS, & p53 mutations exist.

 

UV radiation, especially cumulative lifelong UVR radiation, is the main predisposing factor for LM/LMM. In contrast to nodular melanomas (NM) & superficially spreading melanomas (SSM), which are linked to severe irregular UVR radiation, investigations have shown that LM/LMM is substantially connected with persistent UVR visibility. According to an Australian study, LM risk increases with time spent in Australia, the number of hours spent in the sun, the number of actinic injuries, and a history of nonmelanoma skin carcinoma.

In addition, LM/LMM is more likely to affect the face, which is a location of persistent sun exposure, whereas SSM & NM are more likely to affect men’s trunks and women’s legs, which are both more frequently covered. Last but not least, LM tends to affect elderly patients in comparison to SSM & NM, possibly because older people have had more lifetime sunlight exposure.

X-ray exposure, estrogen/progesterone, & non-permanent hair colors have all been proposed as potential factors in addition to UV radiation. In addition, LM is more prone to develop in people with UV sensitivity-related genetic disorders such as Werner syndrome, xeroderma pigmentosum, oculocutaneous albinism, & porphyria cutanea tarda. No correlations with drinking or smoking have been shown.

 

Excellent outlook for LM/LMM. There were no disease-related fatalities for LM and just one for LMM in a study of 270 individuals with LM/LMM who underwent total excision. The disease-specific rate of survival at five and ten years was 100 & 97.1%, accordingly. So, LM by itself does not shorten life expectancy.

After adjusting for Breslow depth, the prognosis is identical for all other melanoma once the tumor becomes metastatic, however, it can be fairly bad if the illness spreads (five-year survival rate is 9 to 27%). Given the potentially huge surface area on the head and neck that may be implicated and the requirement for extensive surgical removal & rebuilding, morbidity for patients can be severe even though mortality is minimal.

 

Clinical History

Lentigines can have a wide range of early appearances depending on the following factors:

  • Race
  • Exposure history
  • Genetic propensity
  • Depending on the type of lentigo, additional considerations

 

Physical examination

Depending on the lesion’s type, lentigines differ in both physical characteristics and their physical shape.

Lentigo simplex

The most typical type of lentigo is called lentigo simplex (also known as simple lentigo or juvenile lentigo). Neither exposure to the sun nor systemic illness are causes of lentigo simplex. Clinically, the lesions are 3–15 mm in diameter, round or oval, asymptomatic macules. They might have smooth or angular borders. The color of the pigmentation, which ranges from brown to black, is uniformly spread. The lesions can appear anywhere on the skin or mucous membranes and are often harmless. The lesions often grow over time, but they can also be present from birth or occur earlier. An imatinib mesylate-treated patient with familial gastrointestinal stromal tumor syndrome saw a decrease in the number of multiple dysplastic nevi and lentigines. It is not entirely clear how imatinib affects pigmentation.

Solar lentigo

The most frequent benign sun-induced lesion that develops in sun-exposed areas is solar lentigo, which includes senile lentigo, actinic lentigo, sunspots, and liver spots. The face, arms, hands, & upper half of the trunk are the areas of the body where solar lentigo most frequently manifests. The spots have a smaller beginning diameter than 5 mm. Lesions often have a flat and depressed surface that may also include subtle wrinkling. The lesions are typically brown, although they can also be black, yellow-tan, or other colors. Lesions that are older tend to be dark brown or brownish black. Lentigines on the sun get bigger and more numerous with time. Huge patches are eventually formed when numerous lesions combine. Despite the fact that people in their 30s and 50s are most likely to develop these lesions, younger people are already exhibiting them due to increased sun exposure and the use of artificial UV light sources. Although they are frequently referred to as liver spots, they are not a symptom of a systemic illness.

Ink-spot lentigo

A wiry or beaded, noticeably uneven outline helps to recognize ink-spot lentigo (also known as reticulated black solar lentigo), a condition that affects persons with Celtic ancestry. Most benign lesions resemble an ink stain and have a reticulated pattern. Similar to solar lentigo, the distribution is restricted to skin-exposed regions of the body; however, unlike solar lentigines, individuals typically only have one ink-spot lentigo. These lesions can also be recognized from the darkly pigmented PUVA lentigo by the many central and peripheral skip areas and more reticulated and beaded patterns. Due to their dark hue, irregular border, and rarity, ink-spot lentigines may at first be mistaken for melanoma; however, further examination, which may involve biopsy, shows the distinctive characteristics of these benign tumors.

Radiation lentigo

While radiation lentigo mimics UV-induced lentigo, it also frequently consists of other histopathologic indicators of long-term epidermal radiation damage, such as keratosis, telangiectasias, subcutaneous fibrosis, and epidermal atrophy. A radiation lentigo is thought to be a sign of previous skin exposure to a high dose of ionizing radiation (e.g., the Chernobyl nuclear accident exposure). There is no evidence that these lesions develop after localized, fractionated radiation treatment. Lentigines caused by radiation can last for up to 4 months after the original exposure. The lesions’ propensity for malignancy is uncertain, however, ionizing rays have never been confirmed to cause melanoma.

PUVA lentigo

A persistent, light brown macule known as PUVA lentigo appears six months or more after the beginning of PUVA treatment for psoriasis. Although the lesions resemble solar lentigines, they frequently have more erratic borders and may look like ephelides. Lesions are closely connected with higher cumulative doses of PUVA, and they can occur at any treatment location. The upper portion of the chest and back, as well as the glans, penis, groin, buttocks, & penile shaft, are the most frequently affected locations. The gluteal cleft, axillae, palms, and soles are unharmed. The lesions range in size from 3 to 8 mm. However, stellate lesions can be up to 3 cm in diameter. After the therapy is stopped, the lentigines may continue for three to six months. Stellate lesions, on the other hand, might last for more than two years.

Oral & labial melanotic macules

Labial and oral melanotic macules are comparable. The lower lip’s vermilion is usually often the site of labial lesions, which can be brown, blue, or blue-black in hue. Variegated pigmentation might happen occasionally. The lesions are often symmetric, asymptomatic, and isolated. The gingiva, palate, buccal mucosa, & tongue can all develop oral lesions.

Vulvar & penile lentigo

The benign lesions known as penile and vulvar lentigo resemble labial melanotic macules. The glans penis, corona sulcus, corona, & penile shaft in men are the most frequently affected areas. The lesions have uneven borders & skip sections, and their colors range from tan to brown to dark brown. The diameter of a single lesion might reach 15 mm. When it comes to women, the lesions show up as a mottled, pigmented patch with skip patches anyplace on the vaginal mucosa. The diameter might range from 5 to 15 mm or more. After labor, episiotomy scars may also develop lesions. In the LAMB syndrome, lentigos affecting the external genitalia have also been documented.

Agminated lentiginosis

Agminated (segmental, unilateral, or partial unilateral) lentiginosis is distinguished by an abundance of lentigines that are contained inside a body segment and have a clear midline demarcation. One or more dermatomes frequently match the distribution. Less frequently, the lesions might be spread in midline clusters, unilaterally, bilaterally, or in a checkerboard pattern. The condition often first manifests in early childhood, though lentigines can also be seen before birth. Numerous diseases have been linked to these lesions. On healthy background skin, the lesions show up clinically as confined, tan, or dark brown macules.

Lentigines profuse

Lentigines profuse (also known as generalized lentigines) are characterized by a large number of lentigines with no signs of related abnormalities or causative factors. Although it has a vast prevalence, lentigines profusa has a clinical presentation similar to ephelides. The trunk, extremities, palms, & genitalia are frequently involved. Conjunctiva and other mucosal surfaces may also be impacted, while the buccal mucosa may be unaffected. The macules range in size from 1 mm to 2 cm. The macules are a variety of colors, from dark brown to black.

Xeroderma pigmentosum

The autosomal-recessive disorder known as Xeroderma pigmentosum (XP) is characterized by defects that result from cells’ inability to repair DNA damage brought on by exposure to UV radiation and certain chemicals. Clinically, patients exhibit increasing pigmentary alterations and skin shrinkage. Neoplastic skin alterations then develop, frequently in youth; basal cell and squamous cell carcinomas are the most prevalent malignancies. There may also be an increase in malignancies like melanoma. The head, neck, and face, in particular, are sun-exposed locations where all of these neoplastic alterations develop.

LEOPARD syndrome

The LEOPARD syndrome, also known as multiple lentigines syndrome, is a complex dysmorphogenetic disorder that is passed on as an autosomal-dominant trait with variable penetrance. It is characterized by lentigines, electrocardiographic conduction defects, ocular hypertelorism, pulmonary stenosis, abnormal genitalia, retardation of growth, and deafness. There may be evidence of a PTPN11 gene mutation. Since most patients only meet three to five of the criteria, making the diagnosis can take time and effort. Although they are not necessary for the diagnosis of LEOPARD syndrome, lentigos are the most typical hallmark of the illness.

Peutz-Jeghers syndrome

A highly penetrant autosomal-dominant disorder known as Peutz-Jeghers syndrome is characterized by gastrointestinal polyps and colored macules. The jejunum is frequently affected by benign hamartomas known as polyps, which can affect the entire gut. Recurrent perirectal bleeding and stomach pain are brought on by these polyps. Intussusception or bleeding that presents as a blockage, abdominal discomfort, rectal prolapse, nausea, and currant spongy stools is frequently present when patients are first examined.

Inherited patterned lentiginosis

Blacks may get hereditary patterns of lentiginosis. On the cheeks and lips, this type is distinguished by hyperpigmented macules. Additional lesions can occasionally be found on the palmoplantar surfaces, knees, elbows, and buttocks. The oral mucosa does not have lesions, and they do not appear to increase the risk of cancer or affect any organs. The inheritance is autosomal dominant. Families with red-haired ancestors and light-skinned African Americans, some of whom have a mixed history with American Indians, are particularly impacted.

Nevus spilus

The nevus spilus is a rare neoplasm with a small chance of turning into melanomas. It is both lentigo and melanocytic. Multiple pigmented papules or macules inside a naturally occurring or acquired pigmented area serve as clear indicators.

 

Differential Diagnoses

Seborrheic Keratosis

Porokeratosis

Freckles/Ephelides

Actinic Keratosis

 

The preferred course of treatment is surgical resection. The conventional 0.5 cm operative margins for MIS have been proven in numerous studies to be insufficient for LM, with about half of the tumors requiring bigger margins for recurrence & clearance rates around 8 – 20%. Numerous single-center research has called for greater margins of up to 1.0 cm or over, and the National Comprehensive Cancer Network amended its guidelines in 2014 to propose 0.5–1.0 cm margins for MIS.

Recent research by Zitelli & Brodland, who performed Mohs micrographic therapy (MMS) on more than 1500 instances of LM, showed that 1.2 cm margins were necessary to obtain a 97 percent compliance rate. According to expert panels, wide local excision (WLE) is still the gold standard of care for surgical procedures. The MMS, though, maybe superior, according to an increasing number of studies. Several universities have shown the risk of recurrence of 1.8 – 1.9% using MMS & 5.8 to 5.9% utilizing WLE for LM.

Incidence rates with MMS can be as minimal as 0.3 – 0.5% in the hands of a skilled physician using immunohistochemistry. Topical imiquimod 5 percent cream may be a good option for people who don’t want surgery or aren’t good surgical patients, though the evidence is conflicting. For imiquimod, the clinical & histologic remission rates vary from 46 – 78% & 37 – 76%, accordingly. Another viable non-surgical approach is radiation treatment.

Radiation delivery techniques and types can vary, although Grenz rays, or fractionated superficial radiation, are most frequently used. The reported range of recurrence rates is 5 – 14%. Azelaic acid, cryotherapy, laser ablation, 5-fluorouracil cream, & chemical peels are only a few of the additional non-surgical methods that have been described with varying degrees of efficacy. However, the available data is insufficient & inconsistent to make any firm conclusions.

 

mequinol/gluconolactone/ lactobionic acid/ arbutin 

solar:

Apply topical solution containing mequinol (20 mg/1mL) and Tretinoin (0.1 mg/1mL) to the affected region of skin twice a day (morning and evening), a minimum of 8 hours apart



https://www.ncbi.nlm.nih.gov/books/NBK482163/

https://emedicine.medscape.com/article/1068503-differential