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.

Skin moles

Skin moles appear during the first few years of life. Most people have 20-30; some have many more. The common skin mole should be uniformly pigmented, with a regular margin. A halo of pale skin around a skin mole may be seen in adolescence. Occasionally congenital skin moles are large (greater than 1 cm), multiple or confluent (bathing trunk pattern). These lesions carry a risk of malignant transformation. Skin Moles deeper in the dermis appear blue in color. Skin Moles tend to regress in old age. If skin moles change in size, become irregular in shape or pigmentation, itch or bleed they should be regarded as unstable and potentially malignant. Sunburn can irritate and activate skin moles. During pregnancy, skin moles tend to increase in size and darken. Malignant melanomas can arise de novo or from pre-existing skin moles. The incidence of this malignant tumor is increasing, especially in fair-skinned people with high sun-exposure.

Atypical Skin Moles Features

Atypical Skin Moles do not follow an evolutionary pattern of either persistence with stability or differentiation in the direction of ultimate regression, as seen in Common Acquired Melanocytic Skin Moles. Rather, Atypical Skin Moles demonstrate a persistent and disordered growth, evident both clinically and microscopically. The clinical recognition of Atypical Skin Moles focuses on several characteristics that help distinguish them from Common Acquired Melanocytic Skin Moles: shape, border, color, diameter, and surface features. Many of these features may also be seen in melanoma, although often to a greater degree.
1 Shape: The shape may be round or oval, like the common acquired Skin Mole, although asymmetric notching and/or outgrowth of pseudopodia are usually observed in lesions over 3 to 4 mm in diameter.
2 Border: The boundary may be irregular with slightly indiscrete to frankly hazy or fuzzy areas, with traces of pink or brownish pigment spilling into surrounding normal skin.
3 Color: The coloration of Atypical Skin Moles is often variegated, with irregular speckling with tan/brown colors and sometimes including foci of tan/brown/dark brown hues or black pigment. redness may be seen as a component of Atypical Skin Moles but is not normally seen in Common Acquired Melanocytic Skin Moles. This is manifest as a pink background color, the intensity of which may vary from trace to slight to moderate. Sometimes only a focal area of pink or a subtle pink hue at the periphery may be seen. The redness does not blanch readily; the degree of redness varies considerably from lesion to lesion and from patient to patient.
4 Diameter: Atypical Skin Moles are most easily recognized when larger than 5mmin diameter. The Clark group’s initial description of Atypical Skin Moles in BK mole syndrome patients had emphasized that they were frequently 5 to 10 mm or larger, and that size was an important clue in identifying Atypical Skin Moles. Large size, however, is not a prerequisite for the diagnosis of Atypical Skin Moles.
5 Surface features: The surface features within any given Atypical Skin Mole may include macular and papular components. A minimal elevation to tangential lighting is noted in most of them. The skin surface markings may be suggestive of early lichen simplex chronicus, showing subtle elevation and coarsening. Scale is only infrequently noted. Erosion is not seen in the non traumatized Atypical Skin Mole.
The clinical presentation of patients with Atypical Skin Moles seems as varied as the morphology of individual Atypical Skin Moles. The classical type D2 phenotype may be first evident with numerous distinctly large, irregular, variegate Skin Moles, mostly concentrated on the trunk and less numerous on the head, neck, and lower extremities. More commonly, however, Atypical Skin Moles are not strikingly large. Fromseveral to a dozen Atypical Skin Molesmay bemixed among several to several dozen Common Acquired Melanocytic Skin Moles. In patients with a solitary Atypical Skin Mole, it may be located anywhere.

Atypical Skin Moles

The atypical skin mole is a special kind of skin moles, with clinical and histologic features suggestive of an intermediate form between the common acquired skin mole and melanoma. atypical skin moles are important markers for both familial and nonfamilial melanoma. As many as 50% of patients with “sporadic” melanoma have been observed to have atypical skin moles.
The incidence of atypical skin moles in the general population has been estimated to be 1.8% to 10% and possibly as high as 19%. The presence of atypical skin moles has been established as an independent risk factor for melanoma, along with several other cutaneous traits, including red or blonde hair, solar lentigines, skin type 1 or 2, and increased numbers of common acquired skin moles. A clinical study has found the adjusted relative risk of melanoma to be 2 for a single atypical skin mole and 12 for 10 or more atypical skin moles. Another found a relative risk of 1.6 when one to four atypical skin moles were counted and 6.1 for five or more atypical skin moles. The risk ofmelanoma attributable to atypical skin moles may
be further exacerbated by the coexistence of other melanoma risk factors, such as skin type 1 or 2. The increased risk for melanoma is particularly true in the setting of the atypical skin mole syndrome (Dysplastic Nevus Syndrome). Dysplastic Nevus Syndrome encompasses individuals with multiple atypical skin moles arising sporadically or in a setting of a family history of atypical skin moles or melanoma. Dysplastic Nevus Syndrome has been divided into a number of forms. Type A is sporadic dysplastic skin mole without melanoma; type B is familial atypical skin mole without melanoma; type C is sporadic atypical skin mole with a personal history of melanoma; type D-l is familial atypical skin mole with one family member with melanoma; and type D-2 is familial atypical skin mole with two or more family members with melanoma. Meticulous screening of family members may demonstrate that presumptive cases of sporadic Dysplastic Nevus Syndrome are actually familial.
All patients with Dysplastic Nevus Syndrome have an increased risk for developing melanoma, although the magnitude of the risk varies among the Dysplastic Nevus Syndrome types. The relative risk of melanoma is least in patients with Dysplastic Nevus Syndrome types A and B, and has been estimated to be 7 with a cumulative lifetime risk of 6%. The relative risk of melanoma in type D-2 patients may be as high as 1000 or greater compared with the general population. Individuals with Dysplastic Nevus Syndrome also appear to be at an increased risk for multiple primary cutaneous melanomas.One study found a 35.5% cumulative 10-year risk of developing a secondmelanoma in those with Dysplastic Nevus Syndrome and a history of melanoma as compared with a 17% 10-year risk of developing a second melanoma in those with a history of melanoma butwithoutDysplastic Nevus Syndrome . Patients with Dysplastic Nevus Syndrome may also be at increased risk of conjunctival and intraocular melanoma. The recognition of Dysplastic Nevus Syndrome may allow early detection of melanoma and identi?cation of those at risk and provide the opportunity for the initiation of preventive measures.
A great deal of discussion has centered on the validity of the atypical skin mole as a distinct entity and its potential for progression to melanoma. Much disagreement over its nature stems from a lack of uniform clinical and histologic criteria to define it. In fact, even the term atypical skin mole has contributed to the controversy. Strictly speaking, the term atypical is a histologic one. The purist may object to the clinical description of a melanocytic skin mole as “atypical-looking". atypical skin moles generally demonstrate both clinical and histologic evidence of distorted and disordered architecture. A
statement by the National Institutes of Health (NIH) Consensus Conference in 1992 sought to eliminate the variability in nomenclature and recommended that the term dysplastic nevus be replaced with atypical mole and the histologic diagnosis be termed nevi with architectural disorder along with a description of the degree of melanocytic atypia. A 2004 survey revealed that the term dysplastic nevus remains commonplace.