Melanomas by Syed M. Aun Raza

Presenter: Syed M Aun Raza

Topic: MELANOMAS

Melanoma

“Malignant neoplasm of melanocytes occurring on skin and mucosa.”

Types

There are four types in general:

1.Superficial Spreading Melanoma2.Nodular Melanoma3.Lentigo Maligna Melanoma4.Acral Lentiginous Melanoma

A General Overview…

•Occurrence: Most Frequently occurs in the fair-skinned individuals, with median age of diagnosis of fifty three.

•Causative Factor: Exposure to sun.(Actinic Radiation)


•Incidence: Occurs more commonly in males than females.

•Age: Mostly occurs in the 40 to 60 –year age group.


•Sites For Oral Melanoma: Most commonly arise on the hard palate and maxillary gingiva.•Clinical Appearance: They can be dark brown, bluish black or black.

Growth Phases

In general there are two growth phases (Nodular melanoma is an exception):

1. Radial Growth Phase2. Vertical Growth Phase

Growth Phases

•During the radial phase the neoplastic cells spread laterally in all the directions. •During the vertical phase the neoplastic cells invade the connective tissue.

Superficial Spreading Melanoma

Important Points:•Most common type of melanoma on the skin and mucous membranes, accounting for 80% of all the lesions.

•Most commonly found in the middle age patients.

•Often arises from a dysplastic nevus

Clinical Features

•Appears as irregularly shaped brown-black area with jagged borders and satellite lesions.

•Satellite lesions are the sites where nodular melanoma may develop.

Clinical Features

•The radial growth phase consists of tan, brown or black variegated macule or plaque.

•Often associated with one or more satellite lesions.

•Intensely pigmented and large in size during this phase.

Histopathology

•Radial growth phase is characterized by large atypical melanocytes.

•Nodular phase is characterized by the invasion of the connective tissue by tumor cells.

•Individual melanocytes exhibit pale cytoplasm & melanin fragments.

Histopathology

•The term “Pagetoid” is used to describe the intraepithelial growth pattern in Superficial spreading melanoma.

•Mitotic figures may or may not be present.

Diagnosis & Treatment

•Diagnosis is confirmed with positive immunohistochemical stains.

•Surgical excision.

Nodular Melanoma

Important Points:•Second most common form of melanomas, accounting for 15% of these lesions.

•I t differs significantly from other types by having little or no radial growth.

•Exhibits a prominent vertical growth phase.

Clinical Features

•Lesion consists of pink, red and black nodules many of which are ulcerated.

•Evidence of metastasis is found earlier in the disease process.

Histopathology

•Cells exhibit a variety of morphology.

•Most common being epithelioid , spindle-shaped and lymphocyte like cells.

•Normal and abnormal mitotic figures.

Histopathology

•Melanin deposition is sporadic.

•Surface epithelium at the margins of the tumor is usually free of the malignant cells indicating absence of radial growth phase.

Growth Comparison b/w Superficial Spreading & Nodular Melanoma

Acral Lentiginous Melanoma

•Important Points:

•Third most common form of melanomas, accounting for 8% of the total lesions.

•It has a mucosal counterpart, termed “Mucosal Lentiginous Melanoma.”

Clinical Features

•Primarily arises on the palms of the hands, soles of the feet and nail beds.

•In the radial growth phase it appears as a brown variegated macule.

Clinical Features

•As the tumor enlarges, it becomes ulcerated, papular, or nodular .

•In the mouth Mucosal Lentiginous Melanoma is indistinguishable from superficially spreading melanoma.

Histopathology

•In the macular phase there is a basilar proliferation of large atypical melanocytes.

•In the papular stage there are confluent masses of neoplastic melanocytes that exhibit spindle shape.

Histopathology

•Marked infiltrate of lymphocytes that assume a lichenoid appearance.

•Mitotic figures may or may not be present.

Lentigo Maligna Melanoma

Important Points:

•An uncommon form of melanoma, representing 5% of the total lesions.

•It usually arises from a pre-existing lesion called “Hutchinson melanotic freckle.”

Clinical Features

•Occurs on the sun exposed areas of the skin, primarily on the cheeks and temples.

•Presents a large, variegated macular lesion.

Clinical Features

•Color varies from light tan to black.

•Most common in white males and females.

Histopathology

•Epithelium is atrophic.

•In the radial phase atypical melanocytes are present with variable amount of coarse melanin granules.

•In the invasive phase they exhibit neoplastic melanocytes that are spindle shaped.

Histopathology

•In early invasive phase exhibit fibroblastic and lymphoblastic host response.

•Atypical melanocytes can be singularly scattered.

What's New????

Drugs that block PD-1 and PD-L1

Melanoma cells may use natural pathways in the body to help avoid the immune system. For instance, they often have a protein called PD-L1 on their surface that helps them evade the immune system. New drugs that block the PD-L1 protein (or the PD-1 protein on immune cells called T cells) can help the immune system spot the melanoma cells and attack them. Studies of these new drugs are now being done.

What's New????

Melanoma vaccines

Weakened melanoma cells (or certain substances found in these cells) can be given to a patient to try to make the body’s immune system kill the cancer cells. This is something like the way we use vaccines to destroy viruses that cause polio, measles, and mumps. But making a vaccine against a tumor like melanoma is harder than making a vaccine to fight a virus. Clinical trials are going on to test the value of treating people with advanced melanoma using vaccines, sometimes combined with other treatments. The results of these studies have been mixed so far, but newer vaccines may hold more promise.

Sources

1. Wikipedia2. Cancer.org3. dermnetnz.org4. Contemporary Oral and Maxillofacial

Pathology

Melanomas by Syed M. Aun Raza

Health & Medicine

Transcript of Melanomas by Syed M. Aun Raza