Lentigo Maligna is a form of melanoma that usually appears as an unevenly pigmented brown patch on areas of skin with long-term sun exposure, particularly on the head and neck. The lesion was initially described in 1890 by Hutchinson, who termed it “Hutchinson’s melanotic freckle.” For much of the early 20th century, its slow-growing nature led to misconceptions about its behavior, and it was variously classified as benign, infectious, or a premalignant condition, under labels such as “junctional nevus,” “infective senile freckles,” and “circumscribed precancerous melanosis.” It wasn’t until the late 1970s and 1980s that key studies by Silvers, Ackerman, and others established its true malignant potential.
Epidemiology
Lentigo maligna and its invasive counterpart, lentigo maligna melanoma (LMM), represent the third most common type of melanoma, following superficial spreading melanoma (SSM) and nodular melanoma. They account for approximately 4% to 15% of all melanoma cases and up to 26% of those occurring on the head and neck. The average age at diagnosis ranges from 66 to 72 years, which is notably older than the typical onset for other melanoma subtypes, generally diagnosed between ages 45 and 57. Women are more frequently diagnosed than men, with a reported female-to-male ratio of 1.7:1, and tend to be diagnosed at a slightly older age.
Over recent decades, the incidence of lentigo maligna and LMM has shown a marked increase. For instance, data from Olmsted County, Minnesota, revealed a rise in incidence from 2.2 cases per 100,000 person-years during 1970-1989 to 13.7 cases per 100,000 person-years between 2004 and 2007.
Anatomy
Pathophysiology
Melanoma carries one of the highest mutation rates among all cancers, and lentigo maligna along with lentigo maligna melanoma shows an especially high mutational burden due to long-term exposure to ultraviolet radiation. This radiation causes oxidative DNA damage and results in characteristic mutations such as cytosine to thymine and cytosine-cytosine to thymine-thymine transitions. These mutations disrupt critical genes involved in the MAPK and PI3K signaling pathways, including BRAF, NRAS, and KIT. Additional mutations in genes like CCND1, CDKN2A, and TP53 contribute to the transformation of lentigo maligna into an invasive melanoma. Compared to other melanoma types, lentigo maligna and its invasive form are more likely to have KIT mutations, while BRAF mutations are more prevalent in other subtypes. Mutations in CCND1, MITF, NRAS, and TP53 also play important roles in disease development and progression.
Etiology
The primary risk factor for developing lentigo maligna and lentigo maligna melanoma is ultraviolet radiation exposure, particularly the cumulative effect of lifetime sun exposure. Multiple studies have shown a strong link between chronic ultraviolet radiation exposure and the development of these subtypes, distinguishing them from nodular melanoma and superficial spreading melanoma, which are more commonly associated with intermittent, intense ultraviolet exposure. One study from Australia reported that the risk of lentigo maligna increased with the number of years an individual lived in the country, total hours of sun exposure, degree of actinic skin damage, and personal history of nonmelanoma skin cancer.
Lentigo maligna and its invasive form are most frequently found on the face, an area commonly affected by long-term sun exposure. In contrast, superficial spreading melanoma and nodular melanoma tend to appear on the trunk in men and on the legs in women, areas that are typically less exposed to the sun. Lentigo maligna also tends to occur in older individuals, likely due to the accumulation of ultraviolet damage over time.
Genetics
Prognostic Factors
The overall prognosis for lentigo maligna and lentigo maligna melanoma is highly favorable. In a study involving 270 patients who underwent complete surgical excision, there were no deaths related to lentigo maligna and only one death attributed to lentigo maligna melanoma. The disease-specific survival rates were reported to be 100 % at five years and 97.1 % at ten years, indicating that lentigo maligna by itself does not significantly impact life expectancy.
However, once the tumor becomes invasive, its prognosis aligns with that of other melanoma subtypes when adjusted for Breslow depth. If the disease progresses to metastatic melanoma, outcomes become much more serious, with five-year survival rates ranging from 9% to 27%. Although the risk of death is relatively low in early stages, patients may still experience considerable morbidity due to the large areas of skin, particularly on the head and neck, that may require extensive surgical removal and complex reconstruction.
Clinical History
Age group
Lentigo maligna and lentigo maligna melanoma (LMM) most commonly affect older adults, typically those aged 60 years and above. The average age at diagnosis ranges from 66 to 72 years, which is significantly older than the average for other melanoma subtypes, such as superficial spreading melanoma or nodular melanoma, which are more often diagnosed between 45 and 57 years.
Physical Examination
Location:
Commonly found on sun-exposed areas, especially the face, including the cheeks, nose, and temples.
Appearance:
Flat or slightly raised macule
Irregular borders
Variegated pigmentation-shades of brown, black, gray, or tan
May have areas of hypopigmentation or depigmentation
Size:
Often large (can exceed several centimeters) due to prolonged, slow growth.
Surface:
Usually smooth, but may develop nodularity, thickening, or ulceration if invasive (LMM).
Symmetry:
Often asymmetric in shape and pigmentation.
Age group
Associated comorbidity
Chronic actinic damage (photoaging)
Nonmelanoma skin cancer (NMSC)
Genetic disorders with sun sensitivity
Immunosuppression
Associated activity
Acuity of presentation
Slow onset: Gradually enlarging, irregularly pigmented macule on chronically sun-damaged skin, typically the face.
Asymptomatic early: Usually painless with no itching or bleeding; often detected incidentally or for cosmetic reasons.
Progression to invasive LMM: May develop nodularity, color changes, or ulceration, prompting urgent evaluation.
Differential Diagnoses
Solar lentigo
Early or macular seborrheic keratosis
Lichen planus-like keratosis
Pigmented actinic keratosis
Benign melanocytic hyperplasia
Desmoplastic melanoma
Laboratory Studies
Imaging Studies
Procedures
Histologic Findings
Staging
Treatment Paradigm
Surgical Therapies
Surgical excision is the primary treatment for lentigo maligna. Traditional 0.5 cm margins have proven insufficient, with nearly half of cases requiring wider margins and recurrence rates ranging from 8% to 20%. Updated guidelines from the National Comprehensive Cancer Network (NCCN) now recommend 0.5 to 1 cm margins, though some studies support margins exceeding 1 cm. A large study by Zitelli and Brodland found that a 1.2 cm margin during Mohs micrographic surgery (MMS) achieved a 97% clearance rate.
While wide local excision is still the standard approach, emerging evidence suggests MMS may offer better outcomes. Studies show recurrence rates of 1.8% to 1.9% with MMS compared to 5.8% to 5.9% with wide excision. When performed by experienced clinicians using immunohistochemistry, MMS recurrence rates can drop as low as 0.3% to 0.5%.
Nonsurgical Therapies
For patients unable or unwilling to undergo surgery, topical imiquimod 5% cream is a potential alternative, though results are variable. Reported clinical and histological clearance rates range from 46%-78% and 37%-76%, respectively.
Radiation therapy, particularly fractionated superficial radiotherapy (Grenz rays), is another nonsurgical option, with recurrence rates reported between 5% and 14%. Other alternatives such as laser ablation, cryotherapy, azelaic acid, 5-fluorouracil cream, and chemical peels have been explored, but current evidence remains limited and inconsistent.
Environmental modifications play a key role in preventing lentigo maligna, especially in high-risk individuals. Since chronic sun exposure is a major risk factor, protective measures should be emphasized. These include:
Sun protection strategies, such as wearing wide-brimmed hats, long-sleeved clothing, and UV-protective sunglasses.
Daily use of broad-spectrum sunscreen with SPF 30 or higher, even on cloudy days.
Avoidance of peak sun hours (10 a.m. to 4 p.m.) when UV radiation is strongest.
Use of shade whenever possible, especially in outdoor settings.
Regular skin checks for early detection, particularly in individuals with significant sun exposure or a personal/family history of skin cancer.
These preventive actions not only reduce the risk of developing lentigo maligna but also support long-term skin health by minimizing UV-induced damage.
Effectiveness of CTLA-4 Inhibitor in treating Lentigo Maligna Melanoma
Ipilimumab (anti-CTLA-4)
Often used in combination with nivolumab.
Higher toxicity but can improve survival in metastatic cases.
Effectiveness of BRAF and MEK Inhibitors in treating Lentigo Maligna Melanoma
Used only if BRAF V600 mutation is present (rare in LMM compared to other melanoma types):
Lentigo maligna is primarily managed with definitive surgical excision. However, complete removal can be challenging because the atypical melanocytic proliferation often extends beyond what is visible clinically. According to the 2022 guidelines from the National Comprehensive Cancer Network (NCCN), the recommended peripheral surgical margins are based on tumor thickness:
Melanoma in situ: 0.5–1 cm
Tumors ≤1.0 mm: 1 cm
Tumors 1.01–2 mm: 1–2 cm
Tumors 2.01–4 mm: 2 cm
Tumors >4 mm: 2 cm
For extensive melanoma in situ, particularly of the lentigo maligna subtype, the NCCN advises that margins greater than 0.5 cm may be warranted. Supporting this, Kunishige et al. recommend excising at least 9 mm of clinically normal skin for all melanoma in situ variants. Furthermore, for lesions located on the head and neck or those exceeding 1 cm in diameter, even broader margins may be required, and Mohs micrographic surgery is often the preferred approach in such cases.
Lentigo Maligna is a form of melanoma that usually appears as an unevenly pigmented brown patch on areas of skin with long-term sun exposure, particularly on the head and neck. The lesion was initially described in 1890 by Hutchinson, who termed it “Hutchinson’s melanotic freckle.” For much of the early 20th century, its slow-growing nature led to misconceptions about its behavior, and it was variously classified as benign, infectious, or a premalignant condition, under labels such as “junctional nevus,” “infective senile freckles,” and “circumscribed precancerous melanosis.” It wasn’t until the late 1970s and 1980s that key studies by Silvers, Ackerman, and others established its true malignant potential.
Lentigo maligna and its invasive counterpart, lentigo maligna melanoma (LMM), represent the third most common type of melanoma, following superficial spreading melanoma (SSM) and nodular melanoma. They account for approximately 4% to 15% of all melanoma cases and up to 26% of those occurring on the head and neck. The average age at diagnosis ranges from 66 to 72 years, which is notably older than the typical onset for other melanoma subtypes, generally diagnosed between ages 45 and 57. Women are more frequently diagnosed than men, with a reported female-to-male ratio of 1.7:1, and tend to be diagnosed at a slightly older age.
Over recent decades, the incidence of lentigo maligna and LMM has shown a marked increase. For instance, data from Olmsted County, Minnesota, revealed a rise in incidence from 2.2 cases per 100,000 person-years during 1970-1989 to 13.7 cases per 100,000 person-years between 2004 and 2007.
Melanoma carries one of the highest mutation rates among all cancers, and lentigo maligna along with lentigo maligna melanoma shows an especially high mutational burden due to long-term exposure to ultraviolet radiation. This radiation causes oxidative DNA damage and results in characteristic mutations such as cytosine to thymine and cytosine-cytosine to thymine-thymine transitions. These mutations disrupt critical genes involved in the MAPK and PI3K signaling pathways, including BRAF, NRAS, and KIT. Additional mutations in genes like CCND1, CDKN2A, and TP53 contribute to the transformation of lentigo maligna into an invasive melanoma. Compared to other melanoma types, lentigo maligna and its invasive form are more likely to have KIT mutations, while BRAF mutations are more prevalent in other subtypes. Mutations in CCND1, MITF, NRAS, and TP53 also play important roles in disease development and progression.
The primary risk factor for developing lentigo maligna and lentigo maligna melanoma is ultraviolet radiation exposure, particularly the cumulative effect of lifetime sun exposure. Multiple studies have shown a strong link between chronic ultraviolet radiation exposure and the development of these subtypes, distinguishing them from nodular melanoma and superficial spreading melanoma, which are more commonly associated with intermittent, intense ultraviolet exposure. One study from Australia reported that the risk of lentigo maligna increased with the number of years an individual lived in the country, total hours of sun exposure, degree of actinic skin damage, and personal history of nonmelanoma skin cancer.
Lentigo maligna and its invasive form are most frequently found on the face, an area commonly affected by long-term sun exposure. In contrast, superficial spreading melanoma and nodular melanoma tend to appear on the trunk in men and on the legs in women, areas that are typically less exposed to the sun. Lentigo maligna also tends to occur in older individuals, likely due to the accumulation of ultraviolet damage over time.
The overall prognosis for lentigo maligna and lentigo maligna melanoma is highly favorable. In a study involving 270 patients who underwent complete surgical excision, there were no deaths related to lentigo maligna and only one death attributed to lentigo maligna melanoma. The disease-specific survival rates were reported to be 100 % at five years and 97.1 % at ten years, indicating that lentigo maligna by itself does not significantly impact life expectancy.
However, once the tumor becomes invasive, its prognosis aligns with that of other melanoma subtypes when adjusted for Breslow depth. If the disease progresses to metastatic melanoma, outcomes become much more serious, with five-year survival rates ranging from 9% to 27%. Although the risk of death is relatively low in early stages, patients may still experience considerable morbidity due to the large areas of skin, particularly on the head and neck, that may require extensive surgical removal and complex reconstruction.
Age group
Lentigo maligna and lentigo maligna melanoma (LMM) most commonly affect older adults, typically those aged 60 years and above. The average age at diagnosis ranges from 66 to 72 years, which is significantly older than the average for other melanoma subtypes, such as superficial spreading melanoma or nodular melanoma, which are more often diagnosed between 45 and 57 years.
Location:
Commonly found on sun-exposed areas, especially the face, including the cheeks, nose, and temples.
Appearance:
Flat or slightly raised macule
Irregular borders
Variegated pigmentation-shades of brown, black, gray, or tan
May have areas of hypopigmentation or depigmentation
Size:
Often large (can exceed several centimeters) due to prolonged, slow growth.
Surface:
Usually smooth, but may develop nodularity, thickening, or ulceration if invasive (LMM).
Symmetry:
Often asymmetric in shape and pigmentation.
Chronic actinic damage (photoaging)
Nonmelanoma skin cancer (NMSC)
Genetic disorders with sun sensitivity
Immunosuppression
Slow onset: Gradually enlarging, irregularly pigmented macule on chronically sun-damaged skin, typically the face.
Asymptomatic early: Usually painless with no itching or bleeding; often detected incidentally or for cosmetic reasons.
Progression to invasive LMM: May develop nodularity, color changes, or ulceration, prompting urgent evaluation.
Solar lentigo
Early or macular seborrheic keratosis
Lichen planus-like keratosis
Pigmented actinic keratosis
Benign melanocytic hyperplasia
Desmoplastic melanoma
Surgical Therapies
Surgical excision is the primary treatment for lentigo maligna. Traditional 0.5 cm margins have proven insufficient, with nearly half of cases requiring wider margins and recurrence rates ranging from 8% to 20%. Updated guidelines from the National Comprehensive Cancer Network (NCCN) now recommend 0.5 to 1 cm margins, though some studies support margins exceeding 1 cm. A large study by Zitelli and Brodland found that a 1.2 cm margin during Mohs micrographic surgery (MMS) achieved a 97% clearance rate.
While wide local excision is still the standard approach, emerging evidence suggests MMS may offer better outcomes. Studies show recurrence rates of 1.8% to 1.9% with MMS compared to 5.8% to 5.9% with wide excision. When performed by experienced clinicians using immunohistochemistry, MMS recurrence rates can drop as low as 0.3% to 0.5%.
Nonsurgical Therapies
For patients unable or unwilling to undergo surgery, topical imiquimod 5% cream is a potential alternative, though results are variable. Reported clinical and histological clearance rates range from 46%-78% and 37%-76%, respectively.
Radiation therapy, particularly fractionated superficial radiotherapy (Grenz rays), is another nonsurgical option, with recurrence rates reported between 5% and 14%. Other alternatives such as laser ablation, cryotherapy, azelaic acid, 5-fluorouracil cream, and chemical peels have been explored, but current evidence remains limited and inconsistent.
Oncology, Radiation
Environmental modifications play a key role in preventing lentigo maligna, especially in high-risk individuals. Since chronic sun exposure is a major risk factor, protective measures should be emphasized. These include:
Sun protection strategies, such as wearing wide-brimmed hats, long-sleeved clothing, and UV-protective sunglasses.
Daily use of broad-spectrum sunscreen with SPF 30 or higher, even on cloudy days.
Avoidance of peak sun hours (10 a.m. to 4 p.m.) when UV radiation is strongest.
Use of shade whenever possible, especially in outdoor settings.
Regular skin checks for early detection, particularly in individuals with significant sun exposure or a personal/family history of skin cancer.
These preventive actions not only reduce the risk of developing lentigo maligna but also support long-term skin health by minimizing UV-induced damage.
Oncology, Radiation
Ipilimumab (anti-CTLA-4)
Often used in combination with nivolumab.
Higher toxicity but can improve survival in metastatic cases.
Oncology, Radiation
Used only if BRAF V600 mutation is present (rare in LMM compared to other melanoma types):
Dabrafenib + Trametinib
Vemurafenib + Cobimetinib
Encorafenib + Binimetinib
Oncology, Radiation
Lentigo maligna is primarily managed with definitive surgical excision. However, complete removal can be challenging because the atypical melanocytic proliferation often extends beyond what is visible clinically. According to the 2022 guidelines from the National Comprehensive Cancer Network (NCCN), the recommended peripheral surgical margins are based on tumor thickness:
Melanoma in situ: 0.5–1 cm
Tumors ≤1.0 mm: 1 cm
Tumors 1.01–2 mm: 1–2 cm
Tumors 2.01–4 mm: 2 cm
Tumors >4 mm: 2 cm
For extensive melanoma in situ, particularly of the lentigo maligna subtype, the NCCN advises that margins greater than 0.5 cm may be warranted. Supporting this, Kunishige et al. recommend excising at least 9 mm of clinically normal skin for all melanoma in situ variants. Furthermore, for lesions located on the head and neck or those exceeding 1 cm in diameter, even broader margins may be required, and Mohs micrographic surgery is often the preferred approach in such cases.
Oncology, Radiation
Detection & Diagnosis
Clinical exam, dermoscopy, and biopsy to confirm diagnosis.
Pre-Treatment Assessment Assess lesion extent, patient health, and treatment suitability.
Definitive Treatment
First-line: Surgical excision or Mohs micrographic surgery.
Alternatives: Imiquimod cream or radiation for non-surgical candidates.
Post-Treatment Surveillance
Regular follow: Up for recurrence and patient education on skin checks.
Long-Term Prevention: Sun protection, lifestyle changes, and routine skin cancer screening.
Lentigo Maligna is a form of melanoma that usually appears as an unevenly pigmented brown patch on areas of skin with long-term sun exposure, particularly on the head and neck. The lesion was initially described in 1890 by Hutchinson, who termed it “Hutchinson’s melanotic freckle.” For much of the early 20th century, its slow-growing nature led to misconceptions about its behavior, and it was variously classified as benign, infectious, or a premalignant condition, under labels such as “junctional nevus,” “infective senile freckles,” and “circumscribed precancerous melanosis.” It wasn’t until the late 1970s and 1980s that key studies by Silvers, Ackerman, and others established its true malignant potential.
Lentigo maligna and its invasive counterpart, lentigo maligna melanoma (LMM), represent the third most common type of melanoma, following superficial spreading melanoma (SSM) and nodular melanoma. They account for approximately 4% to 15% of all melanoma cases and up to 26% of those occurring on the head and neck. The average age at diagnosis ranges from 66 to 72 years, which is notably older than the typical onset for other melanoma subtypes, generally diagnosed between ages 45 and 57. Women are more frequently diagnosed than men, with a reported female-to-male ratio of 1.7:1, and tend to be diagnosed at a slightly older age.
Over recent decades, the incidence of lentigo maligna and LMM has shown a marked increase. For instance, data from Olmsted County, Minnesota, revealed a rise in incidence from 2.2 cases per 100,000 person-years during 1970-1989 to 13.7 cases per 100,000 person-years between 2004 and 2007.
Melanoma carries one of the highest mutation rates among all cancers, and lentigo maligna along with lentigo maligna melanoma shows an especially high mutational burden due to long-term exposure to ultraviolet radiation. This radiation causes oxidative DNA damage and results in characteristic mutations such as cytosine to thymine and cytosine-cytosine to thymine-thymine transitions. These mutations disrupt critical genes involved in the MAPK and PI3K signaling pathways, including BRAF, NRAS, and KIT. Additional mutations in genes like CCND1, CDKN2A, and TP53 contribute to the transformation of lentigo maligna into an invasive melanoma. Compared to other melanoma types, lentigo maligna and its invasive form are more likely to have KIT mutations, while BRAF mutations are more prevalent in other subtypes. Mutations in CCND1, MITF, NRAS, and TP53 also play important roles in disease development and progression.
The primary risk factor for developing lentigo maligna and lentigo maligna melanoma is ultraviolet radiation exposure, particularly the cumulative effect of lifetime sun exposure. Multiple studies have shown a strong link between chronic ultraviolet radiation exposure and the development of these subtypes, distinguishing them from nodular melanoma and superficial spreading melanoma, which are more commonly associated with intermittent, intense ultraviolet exposure. One study from Australia reported that the risk of lentigo maligna increased with the number of years an individual lived in the country, total hours of sun exposure, degree of actinic skin damage, and personal history of nonmelanoma skin cancer.
Lentigo maligna and its invasive form are most frequently found on the face, an area commonly affected by long-term sun exposure. In contrast, superficial spreading melanoma and nodular melanoma tend to appear on the trunk in men and on the legs in women, areas that are typically less exposed to the sun. Lentigo maligna also tends to occur in older individuals, likely due to the accumulation of ultraviolet damage over time.
The overall prognosis for lentigo maligna and lentigo maligna melanoma is highly favorable. In a study involving 270 patients who underwent complete surgical excision, there were no deaths related to lentigo maligna and only one death attributed to lentigo maligna melanoma. The disease-specific survival rates were reported to be 100 % at five years and 97.1 % at ten years, indicating that lentigo maligna by itself does not significantly impact life expectancy.
However, once the tumor becomes invasive, its prognosis aligns with that of other melanoma subtypes when adjusted for Breslow depth. If the disease progresses to metastatic melanoma, outcomes become much more serious, with five-year survival rates ranging from 9% to 27%. Although the risk of death is relatively low in early stages, patients may still experience considerable morbidity due to the large areas of skin, particularly on the head and neck, that may require extensive surgical removal and complex reconstruction.
Age group
Lentigo maligna and lentigo maligna melanoma (LMM) most commonly affect older adults, typically those aged 60 years and above. The average age at diagnosis ranges from 66 to 72 years, which is significantly older than the average for other melanoma subtypes, such as superficial spreading melanoma or nodular melanoma, which are more often diagnosed between 45 and 57 years.
Location:
Commonly found on sun-exposed areas, especially the face, including the cheeks, nose, and temples.
Appearance:
Flat or slightly raised macule
Irregular borders
Variegated pigmentation-shades of brown, black, gray, or tan
May have areas of hypopigmentation or depigmentation
Size:
Often large (can exceed several centimeters) due to prolonged, slow growth.
Surface:
Usually smooth, but may develop nodularity, thickening, or ulceration if invasive (LMM).
Symmetry:
Often asymmetric in shape and pigmentation.
Chronic actinic damage (photoaging)
Nonmelanoma skin cancer (NMSC)
Genetic disorders with sun sensitivity
Immunosuppression
Slow onset: Gradually enlarging, irregularly pigmented macule on chronically sun-damaged skin, typically the face.
Asymptomatic early: Usually painless with no itching or bleeding; often detected incidentally or for cosmetic reasons.
Progression to invasive LMM: May develop nodularity, color changes, or ulceration, prompting urgent evaluation.
Solar lentigo
Early or macular seborrheic keratosis
Lichen planus-like keratosis
Pigmented actinic keratosis
Benign melanocytic hyperplasia
Desmoplastic melanoma
Surgical Therapies
Surgical excision is the primary treatment for lentigo maligna. Traditional 0.5 cm margins have proven insufficient, with nearly half of cases requiring wider margins and recurrence rates ranging from 8% to 20%. Updated guidelines from the National Comprehensive Cancer Network (NCCN) now recommend 0.5 to 1 cm margins, though some studies support margins exceeding 1 cm. A large study by Zitelli and Brodland found that a 1.2 cm margin during Mohs micrographic surgery (MMS) achieved a 97% clearance rate.
While wide local excision is still the standard approach, emerging evidence suggests MMS may offer better outcomes. Studies show recurrence rates of 1.8% to 1.9% with MMS compared to 5.8% to 5.9% with wide excision. When performed by experienced clinicians using immunohistochemistry, MMS recurrence rates can drop as low as 0.3% to 0.5%.
Nonsurgical Therapies
For patients unable or unwilling to undergo surgery, topical imiquimod 5% cream is a potential alternative, though results are variable. Reported clinical and histological clearance rates range from 46%-78% and 37%-76%, respectively.
Radiation therapy, particularly fractionated superficial radiotherapy (Grenz rays), is another nonsurgical option, with recurrence rates reported between 5% and 14%. Other alternatives such as laser ablation, cryotherapy, azelaic acid, 5-fluorouracil cream, and chemical peels have been explored, but current evidence remains limited and inconsistent.
Oncology, Radiation
Environmental modifications play a key role in preventing lentigo maligna, especially in high-risk individuals. Since chronic sun exposure is a major risk factor, protective measures should be emphasized. These include:
Sun protection strategies, such as wearing wide-brimmed hats, long-sleeved clothing, and UV-protective sunglasses.
Daily use of broad-spectrum sunscreen with SPF 30 or higher, even on cloudy days.
Avoidance of peak sun hours (10 a.m. to 4 p.m.) when UV radiation is strongest.
Use of shade whenever possible, especially in outdoor settings.
Regular skin checks for early detection, particularly in individuals with significant sun exposure or a personal/family history of skin cancer.
These preventive actions not only reduce the risk of developing lentigo maligna but also support long-term skin health by minimizing UV-induced damage.
Oncology, Radiation
Ipilimumab (anti-CTLA-4)
Often used in combination with nivolumab.
Higher toxicity but can improve survival in metastatic cases.
Oncology, Radiation
Used only if BRAF V600 mutation is present (rare in LMM compared to other melanoma types):
Dabrafenib + Trametinib
Vemurafenib + Cobimetinib
Encorafenib + Binimetinib
Oncology, Radiation
Lentigo maligna is primarily managed with definitive surgical excision. However, complete removal can be challenging because the atypical melanocytic proliferation often extends beyond what is visible clinically. According to the 2022 guidelines from the National Comprehensive Cancer Network (NCCN), the recommended peripheral surgical margins are based on tumor thickness:
Melanoma in situ: 0.5–1 cm
Tumors ≤1.0 mm: 1 cm
Tumors 1.01–2 mm: 1–2 cm
Tumors 2.01–4 mm: 2 cm
Tumors >4 mm: 2 cm
For extensive melanoma in situ, particularly of the lentigo maligna subtype, the NCCN advises that margins greater than 0.5 cm may be warranted. Supporting this, Kunishige et al. recommend excising at least 9 mm of clinically normal skin for all melanoma in situ variants. Furthermore, for lesions located on the head and neck or those exceeding 1 cm in diameter, even broader margins may be required, and Mohs micrographic surgery is often the preferred approach in such cases.
Oncology, Radiation
Detection & Diagnosis
Clinical exam, dermoscopy, and biopsy to confirm diagnosis.
Pre-Treatment Assessment Assess lesion extent, patient health, and treatment suitability.
Definitive Treatment
First-line: Surgical excision or Mohs micrographic surgery.
Alternatives: Imiquimod cream or radiation for non-surgical candidates.
Post-Treatment Surveillance
Regular follow: Up for recurrence and patient education on skin checks.
Long-Term Prevention: Sun protection, lifestyle changes, and routine skin cancer screening.
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