Vaginal melanoma is a rare

malignancy Malignancy () is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous ''benign'' tumor in that a malignancy is not ...

that originates from

melanocyte Melanocytes are melanin-producing neural-crest, neural crest-derived cell (biology), cells located in the bottom layer (the stratum basale) of the skin's epidermis (skin), epidermis, the middle layer of the eye (the uvea), the inner ear, vagina ...

s in the

vaginal epithelium The vaginal epithelium is the inner lining of the vagina consisting of multiple layers of (Epithelium, squamous) cells. The basal membrane provides the support for the first layer of the epithelium-the basal layer. The intermediate layers lie u ...

. It is also known as a melanocytic tumor or as a malignant

melanoma Melanoma is the most dangerous type of skin cancer; it develops from the melanin-producing cells known as melanocytes. It typically occurs in the skin, but may rarely occur in the mouth, intestines, or eye (uveal melanoma). In very rare case ...

. It is aggressive and infrequently cured. The median overall survival is 16 months. Vaginal melanoma accounts 5.5% of all

vaginal cancer Vaginal cancer is an extraordinarily rare form of cancer that develops in the tissue of the vagina. Primary vaginal cancer originates from the vaginal tissue – most frequently Squamous-cell carcinoma of the vagina, squamous cell carcinoma, but p ...

s and only 1% of all melanomas diagnosed in women. Vaginal melanomas are frequently diagnosed in advanced stages of the disease. The prognosis is poor and the most important risk factor is the presence of lymph node metastases.

Presentation

This cancer most often develops on the lowest third of the vagina. It is darkly pigmented and of an irregular T-shape, but amelanotic melanomas have been described in 7% of cases. Melanoma of the vagina can be several centimeters in size.

Histology

When the tissue is assessed, the histological characteristics include: * the shape of the cells appear similar to epithelial and spindle-shaped * the growth occurs in the shapes of sheets and nests * the presence of

melanin Melanin (; ) is a family of biomolecules organized as oligomers or polymers, which among other functions provide the pigments of many organisms. Melanin pigments are produced in a specialized group of cells known as melanocytes. There are ...

in the cells * the nucleus of the cells is large and abnormal

Other cancers

Other cancerous conditions arise from vaginal epithelium: * Vaginal squamous-cell carcinoma arises from the

squamous cell Epithelium or epithelial tissue is a thin, continuous, protective layer of Cell (biology), cells with little extracellular matrix. An example is the epidermis, the outermost layer of the skin. Epithelial (Mesothelium, mesothelial) tissues line ...

s of the vaginal epithelium * Vaginal adenocarcinoma arises from secretory cells in the vaginal epithelium * Clear cell adenocarcinoma of the vagina this malignancy arises in some women prenatally exposed to

diethylstilbestrol Diethylstilbestrol (DES), also known as stilbestrol or stilboestrol, is a nonsteroidal estrogen medication, which is presently rarely used. In the past, it was widely used for a variety of indications, including pregnancy support for those with ...

Diagnosis

A biopsy should be obtained from all suspicious lesions and

Immunocytochemistry Immunocytochemistry (ICC) is a common laboratory technique that is used to anatomically visualize the localization of a specific protein or antigen in cells by use of a specific primary antibody that binds to it. The primary antibody allows vis ...

can reveal positive results for S-110 protein, HMB 45 and melan A. Once the diagnosis of vaginal melanoma is established, additional examinations should be performed to exclude the spread to regional lymph nodes or distant organs, as the diagnosis of vaginal melanoma is often delayed. Lymph-node involvement is the most important prognostic factor.

Treatment

Surgery represents the primary treatment modality. Chemotherapy may be ineffective, but

checkpoint inhibitor Checkpoint inhibitor therapy is a form of Treatment of cancer, cancer immunotherapy. The therapy targets immune checkpoints, key regulators of the immune system that when stimulated can dampen the immune response to an immunologic stimulus. Some ca ...

s and BRAF and

MEK inhibitor A MEK inhibitor is a chemical or drug that inhibits the mitogen-activated protein kinase enzymes MEK1 and/or MEK2. They can be used to affect the MAPK/ERK pathway which is often overactive in some cancers. (See MAPK/ERK pathway#Clinical signifi ...

s have been recently tested in vaginal melanomas. Less than 10% of vaginal melanomas have BRAF-mutations. Therefore BRAF-inhibitors play only a minor role in vaginal melanomas (unlike in skin

s). However, a recent study has shown that checkpoint inhibitors (inkluding CTLA-4 inhibitors and

PD-1 inhibitor Cancer immunotherapy (immuno-oncotherapy) is the stimulation of the immune system to treat cancer, improving the immune system's natural ability to fight the disease. It is an application of the fundamental research of cancer immunology (immun ...

s) are effective in the treatment of advanced vulvovaginal melanomas.

References

External links

{{Tumors, state=uncollapsed * Melanoma Vaginal diseases Disturbances of human pigmentation Epithelium