Melanoma

Calcola il rischio di sviluppare un melanoma: (By Siteman Cancer Center)

Emily’s Melanoma risk calculator: (By Victoria Melanoma Service)

Melanoma is a cancer that arises from melanocytes of skin or mucous membrane (eyes or bowel). It is the most aggressive and potentially life-threatening of the three most common types of skin cancer (basal cell carcinoma and squamous cell carcinoma are the other two) and it can have several aspects. Melanoma occurs predominantly in adults. Early signs in a nevus that would suggest malignant change include change in shape and colour, itching, an increase in size. Ulceration or bleeding are later signs. Melanoma occurs more commonly on the extremities of women and on the trunk of men, but it can arise from any site on the skin surface. Prognosis is affected by clinical and histological factors and by anatomic location of the lesion.

Superficial spreading malignant melanoma: accounts for about 2/3 of cases, in men it occurs mostly on the back and in women on the legs, mostly affects young people with an average around 44 years, it’s caractheristics are asymmetry, irregular borders with indentations and variegated. It has an initial radial growth in the upper skin layer that remains for months, and in end-stage deepens affecting even the deep layers of the dermis and subcutaneous tissue. In the second phase it can metastatize.

Nodular malignant melanoma: it rapresents about 15% of all melanomas in Caucasian patients, it is characterized by rapid vertical growth, appears as a nodular or polypoid lesion, black or bluish, rarely amelanotic (in these cases the dermatoscopy can show a pigmentary network at the border of the lesion), often ulcerated or crusted, the borders are smooth, The differential diagnosis involves pigmented seborrheic keratosis, and pigmented basalioma. The prognosis is more severe than other types of melanoma.

Lentigo malignant melanoma: it is the least common type of melanoma, it prevails in the face of elderly people chronically exposed to the sun. It has a slow progression and often takes many months before invading the dermis, and often the size can reach 6 cm. The tumor is asymmetric, the pigmentation is dark and variegated and the borders are irregular. If left untreated it can develop nodular lesions of vertical growth, rarely it metastatizes

Acrolentigginous melanoma: represents approximately 5% of all melanomas in Caucasian race, as it develops mostly in Asians and African Americans (it accounts for 29-72% of melanoma in dark-skinned individuals) . This neoplasm appears on the palms ofthe hands, on the sole of the feet and on nails and usually affects older women. In the early stages it has a radial growth and appears as a blackish-brown patch that extends peripherally and afterward appears a nodular component index of a vertical growth of the tumor. Nail melanoma often affects the cuticle (Hutchinson’s sign) and this differentiates it from other nail disease like melanonichia striata, subungual hemorrhage and nail moles. In advanced stages, bleeding and ulcers appear. Nail’s melanoma is diagnosed with incisional or excisional biopsy of the nail matrix. The cause or causes of acral lentiginous melanoma are unknown. It is not related to sun exposure.

Amelanotic melanoma: Melanoma can sometimes appear as a papular or nodular lesion devoid of pigment, but with dermatoscopy it is possible to see a residual pigment network around the melanoma, so the diagnosis is extremely complex and dermatoscopy in always necessary to evaluate these lesions

Desmoplastic melanoma: it is a fibrosing variant of spindle cell melanoma. the lesions are usually found on the head and neck region and present as bulky firm fibrous masses of tumour or indurated plaques.These are usually amelanotic lesions. Early detection is uncommon. Desmoplasia may be throughout the entire tumor or may be present only in one part of a non-desmoplastic melanoma. They are positive for S-100 protein but are often negative to tyrosinase, gp100, Melan-A. It has a high tendency for local recurrence, but metastases to regional lymph nodes are less common

Metastatic melanoma: often assumes the characteristic of satellitosis near the primary melanoma. Sometimes we can find distant metastases that appear as papules or plaques, not pigmented or brown, black or blue. The involvement of lymph nodes appears as a nodular swelling in the areas of correspondence.

Congenital or infantile melanoma: Congenital and infantile types of melanoma are uncommon conditions for which there are limited epidemiologic data.Disease arising from medium and large/giant congenital nevi was most common, whereas reports of de novo and transplacental disease were infrequent. Six cases of transplacental transmission of melanoma affect- ing a fetus have been reported, and only one of these patients survived long-term. Death of approximately 40% of patients was noted within 18 months of diagnosis. Male infants accounted for approximately 74% of cases. The most commonly affected anatomic sites were the head and neck. The prognosis for congenital and infantile melanoma is poor

Other variants: Rabdhoid melanoma, nevoid melanoma, melanoma on blue naevus, mixoid melanoma, melanoma of mucous membrane