What is dermatopathology? What is melanoma?

some explanations

page 1

Melanoma of the skin

page 2

Histological diagnosis of cutaneous melanoma

page 3

Melanoma arising in a melanocytic nevus

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Infiltration and pseudoinfiltration

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Sweat gland carcinomas

page 6

The sentinel lymph node in cutaneous melanoma

page 7

Bullous cutaneous diseases

page 8

Spitz nevus

page 9

Prognostic factors in cutaneous melanoma

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The dysplastic nevus

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Dermatofibrosarcoma protuberans

page 12

Melanoma in situ

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Merkel cell carcinoma

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Basal cell carcinoma

page 15

Melanoma in paediatric age

last page

Questions, comments, opinions

What is melanoma?
Melanoma is a malignant tumor originating from cells (melanocytes) capable to form a dark pigment (melanin).

Is it true that melanoma diagnosis may be difficult, at microscope too?
Melanoma diagnosis may be difficult either clinically (at naked eye) as well as histologically (at microscope), because moles (or nevi) do exist; nevi are lesions, pigmented like melanoma, but benign.

Does melanoma occur in children?
Melanoma is a tumor occuring in adult juvenile and in advanced ages. It is uncommon under 18 years of age and very rare under 10 years of age.

Is it true that to remove nevi can be dangerous, because it may favour melanoma development?
To remove nevi is not dangerous and does not favor melanoma development.

What are subjects who run an increased risk for melanoma?
The subjects with an increased risk for melanoma are individuals showing fair complexion, blond or red hair and blue eyes.

Which are the skin factors implying an increased melanoma risk?
Factors implying an increased melanoma risk are the total number and the dimension of cutaneous nevi. Individuals having a high number of nevi run a greater increased risk for melanoma than subjects with no or few nevi. Individuals with large nevi have a major melanoma risk than subjects with small nevi.

What can I do to prevent melanoma?
Melanoma is a tumor which mostly arises and grows on the skin, a visible organ. Thus, it is possible efficaciously to prevent it. If you notice a "new" nevus, not existing before, which arises in adult age, changing in shape, dimension or color, you should ask for a medical visit. Subjects with numerous nevi should be periodically visited by a dermatologist, so that their pigmented lesions can be studied and controlled.

Is to remove nevi useful to prevent melanoma?
Melanoma can arise in a preexisting nevus or in a normal skin. Melanomas arising in a preexisting nevus are 20-30% of all tumors; however, the number of nevi which actually becomes malignant is very small. To remove aspecifically nevi is not therefore useful to prevent melanoma. It is mandatory to remove melanomas and nevi which are suspected to undergoing malignant transformation.

What a patient can expect after a diagnosis of melanoma?
Melanoma prognosis depends on the fact if the removed melanoma is an early or an advanced tumor. Early tumors (thin melanomas = thickness less than 1 mm) have good prognosis. Patients with an advanced tumor run a high risk. Thick melanomas, ulcerated melanomas and melanomas with lymph node metastases confer a very high risk.

What is melanoma in situ?
Melanoma in situ is a melanoma in its first phase of growth, when it grows in the same site where it arised (epidermis) and does not invade other structures. Patients with melanoma in situ recover in 100% of cases.

What is regression?
Regression is a inflammation evoked by the tumor, as body reaction against the lesion. Unfortunately, regression is not generally able to destroy all melanoma cells, so that disease goes on.

What is sentinel lymoh node?
Sentinel lymph node is the first lymph node which drains the lymph of a cutaneous area. It is therefore the first site of lymphatic metastasis of melanoma.

Why biopsy of sentinel lymph node is performed?
Sentinel lymph node biopsy is performed to establish the tumor spread and to plan prognosis and treatment. If sentinel lymph node is positive, all regional lymph nodes are removed, to improve survival rate of patients.

Does melanoma occur in the skin only?
Melanoma is a tumor occurring almost always in the skin; however, it may arise in all other sites. More frequent noncutaneous sites are: the eye (choroid melanoma), the nasal cavities, the oral cavity and the vulva.