What is Lentigo maligna melanoma

Lentigo Maligna Melanoma

Gender: equally common in males and females.

Age incidence: usually in older people.

Anatomic location: affecting the face, neck or dorsal arms (sun-exposed).

Color: uniform, but red and white discoloration may occur later.

Appearance: flat and irregularly outlined, lesions tend to look mottled or washed out and often contain areas of normal pigmentation.

What is the significance of nodularity and ulceration in Lentigo maligna melanoma? indicate local invasion.

What explains the complex pattern of Lentigo maligna melanoma? they develop over years or decades, these years of migration and regression can produce lesions with a shape more varied and bizarre than that of Superficial Spreading Melanoma.

What is Lentigo maligna? represents in situ or intraepidermal melanoma.

What is the natural history of Lentigo maligna? progression to invasive lentigo maligna melanoma occurs in 5% of patients.

What is Acral lentiginous melanoma

Acral lentiginous melanoma

Prevalence: accounts for 7% of all melanomas.

Anatomic sites: occurs primarily on the hands and feet, including about the nails, also occur on the modified skin around the mouth, anus and genitalia.

Course: develops and evolves over years.

Gender: more common in males than females.

Age incidence: usually in older people.

Ethnic groups: the most common form of melanoma in the skin of Asian and Black people, accounting for more than half of melanomas in these groups. It is the least common form of melanoma in Caucasian people.

Appearance: flat slowly expanding pigmented macule with a fairly uniform, mottled color.

What is Hutchinson's sign? sudden appearance of a pigmented band originating at the proximal nail fold or pigmentation in the proximal or distal nail fold.

Significance of Hutchinson's sign: suggestive of acral-lentiginous melanoma.

What is Nodular melanoma

Prevalence: accounts for about 10-15% of all cases of melanoma.

Incidence: more frequent in males than females, with a ratio of 2:1. Nodular melanomas occur most often in the fifth or sixth decade.

Site: Nodular melanomas affect any area of skin, but are more often found on the extremities.

Course: Nodular melanoma lesions appear and evolve over months and tend to extend vertically in the skin.

Appearance: Nodular melanoma is most commonly dark brown, red-brown, or red-black and is dome-shaped, polypoid, or pedunculated. It is occasionally amelanotic or flesh colored and resembles flesh-colored dermal nevi or basal cell carcinoma. These amelanotic melanomas represent 2% of all melanomas. Lesions eventually erode, ulcerate and bleed.

Differential diagnosis: Hemangioma which is compressible with its color density changed with firm finger pressure.

What is Superficial Spreading Melanoma

Prevalence: the most common subtype of melanoma, accounting for 70-80% of all cases.

Incidence: most common in middle age, from the fourth to fifth decade, slightly more common in females than males and usually affects Caucasians.

Anatomic site: Any area of the skin may be affected but they are most often found on the upper back of both men and women and on the legs of women.

Clinical appearance: Superficial Spreading Melanoma lesions tend to be greater than 6 mm in diameter, flat and asymmetric with varying colors.

Specific features: The hallmark of Superficial Spreading Melanoma is the haphazard combination of many colors, but it may be uniformly brown or black. Colors may become more diverse as time proceeds. A dull red color is frequently observed, which may occupy a small area or may dominate the lesion.

Course: Superficial Spreading Melanoma begins in a pre-existing lesion, in a nonspecific manner and then changes shape by radial spread and regression.
The radial growth phase (lateral spread of lesions within the skin): may last for months or for years, before nodules develop. The random migration of cells, along with the process of regression, results in lesions with an endless variety of shapes and sizes. The shape is bizarre if left untreated for years.