Malignant Melanoma

About malignant melanoma

Malignant melanoma is a malignant neoplasm comprised of melanocytes and nevus cells, both of which are pigment-producing. It is typified by irregularity in shape and color, and eventually a palpable papule or plaque. There are four types of malignant melanoma: superficial spreading, lentigo maligna, nodular, and acral lentiginous.

Lentigo maligna melanoma. This form usually occurs in sun-exposed areas, such as the head and neck, and most frequently occurs in the elderly (median ~70 yrs old). It is multicolored and variably elevated in some areas. It is preceded by  in situ melanoma, or lentigo maligna.

Superficial spreading. This is the most common form of melanoma. It is not associated with sun-exposed surfaces, and can often be found on the back or legs. Median age of onset is ~50 years. It is irregular in color, border, and surface texture.

Nodular. This form occurs on all skin surfaces, with a median age of onset of ~50 years. It is a rapidly growing, blue-black nodule, that may be eroded.

Acral lentiginous. This form occurs on the palms and soles and, in contrast to the other forms, occurs most frequently in Blacks and Asians. It has a median onset of ~60 years of age. It has irregular borders and a black color.

With what can malignant melanoma be confused?

Lentigo maligna melanoma can be confused with actinic lentigo or, sometimes, seborrheic keratosis. A superficial spreading melanoma can resemble pigmented basal cell carcinoma or a nevus or, less often, seborrheic keratosis or angioma. Nodular melanoma can be confused with blue nevus (a blue nodule that begins in childhood), pyogenic granuloma, angioma, or dermatofibroma. The acral lentiginous variety can mimic a nevus or a rare fungal infection termed tinea nigra palmaris.

How is malignant melanoma diagnosed?

A new pigmented lesion, or one that increases in size or changes color, areworrisome signs that often prompt patients to seek medical care. Other suspicious signs are bleeding or itching of a pigmented lesion. Some patients have a family history of melanoma, prompting increased scrutiny. Your dermatologist may examine the lesion with a special lens called a dermatoscope to aid in diagnosis. The classic ABCDEs of melanoma detection are asymmetry, border irregularity, color variegation, diameter greater than 6 mm, and evolving, or changing in size, shape or color. However, not all malignant melanomas follow the ABCDE rules; any suspicious pigmented lesion should be examined by biopsy, excisional when possible, with 2 to 3 mm margins. If the lesion is large, such as often occurs with lentigo maligna melanoma, incisional biopsy is acceptable.

How is malignant melanoma treated?

Excision is the treatment of choice when melanoma is detected early. The required margin is determined by the depth of cancer invasion, with deeper lesions requiring wider margins. The surgeon may perform sentinel lymph node mapping, in which a tracer is injected in to the lesion to determine the first draining lymph node. This node can then be examined to determine whether malignant cells have spread. The potential benefit of lyphadenectomy is determined by the stage of the cancer. If the melanoma has metastasized, chemotherapy and/or immunotherapy is required; excision will not be curative. Melanoma is treated by specialists including a surgeon and an oncologist. Frequent follow-up is required. Melanoma vaccines are still in the research and development stage.

What is the prognosis for malignant melanoma?

The lentigo maligna, superficial spreading and acral lentiginous types of melanoma have a “horizontal” growth phase, during which the lesion is flat or slightly raised. The lesion is completely curable by excision during this phase, and prognosis is directly related to the thickness of the tumor, ranging from a 5 year survival of 99% to 22% . Therefore, early detection is crucial. Nodular melanoma unfortunately only has a “vertical” growth phase.

How is malignant melanoma prevented?

Sunlight is likely a risk factor in some types of melanoma, as is family history. A large number of small nevi, large nevi, or dysplastic nevi are also risk factors. Prudent avoidance of sunlight irradiation is always recommended. Close physician follow-up for patients with risk factors is recommended, with the exact frequency determined by the risk factors and prior duration of follow-up.

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Squamous Cell Carcinoma

About squamous cell carcinoma

Squamous cell carcinoma is a commonly occurring malignant growth derived from epidermal keratinocytes. It appears as an indurated (hard), scaling or crusted plaque or nodule that may ulcerate or bleed. A number of risk factors contribute to the development of squamous cell carcinoma, including exposure to ultraviolet radiation and chemical carcinogens. It is more common in light-skinned people with frequent sun exposure, such as farmers and outdoor laborers. The incidence of the disease increases with proximity to the equator. Not surprisingly, it occurs most often on sun-exposed areas such as the head, neck, and arms. It also can arise in sites of damaged skin or mucous membranes, such as burn injuries. The lower lip is frequently involved as a result of chronic injury from smoking or sun damage. Squamous cell carcinoma can be very locally invasive, and also harbors the capacity to metastasize to distant sites.

With what can squamous cell carcinoma be confused?

Squamous cell carcinoma must be distinguished from basal cell carcinoma, actinic keratosis, warts, keratoacanthoma, seborrheic keratosis, and Bowen’s disease and, on the penis, from erythroplasia of Queyrat.

How is squamous cell carcinoma diagnosed?

Any ulcer that fails to heal should undergo biopsy to rule out squamous cell carcinoma.

How is squamous cell carcinoma treated?

Excision is the preferred therapy. Small lesions can be effectively destroyed with cryotherapy, curettage or electrodessication, but it is often preferable to obtain a tissue sample. Larger tumors and those on cosmetically sensitive areas, such as the face, may be removed using the Mohs micrographic surgery technique. Sun protection with sunscreen, protective clothing, and sun avoidance is necessary to reduce the risk of further tumors.

What is the prognosis for squamous cell carcinoma?

Only about 2% of squamous cell carcinomas metastasize. Large, poorly differentiated, deeply invading carcinomas and those arising in scars or mucous membranes are more likely to do so.

More on squamous cell carcinoma

Image links

Loyola University Medical education Network: Squamous Cell Carcinoma of the Cheek

Other useful links

Skin Cancer Foundation: Squamous Cell Carcinoma

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Basal Cell Carcinoma

About basal cell carcinoma

Basal cell carcinoma (BCC) is a cancer arising from the basal cell layer of the epidermis. It is the most commonly occurring human cancer. Despite only rarely metastasizing, these aggressive tumors can cause profound local tissue destruction. The majority of basal cell carcinomas are caused by exposure to ultraviolet radiation in the form of sunlight. It occurs most frequently in fair-skinned, light-eyed individuals with other evidence of sun-damage to their skin.

There are four subtypes of BCC: nodular, pigmented, superficial, and sclerotic. The nodular type is most common, appearing as the classic “pearly papule” with a central depression, associated telangiectasia (small blood vessels), and a rolled, waxy border. It is often found on the face, especially the nose. The pigmented type, as the name suggests, is a blue or black nodule, papule, or plaque, often speckled, with a rolled border. Superficial BCC appears similar to eczema, and is often found on the trunk. It is red, scaly, well-demarcated, and has a pearly border. The scarring type appears as a white atrophic plaque that can be confused with a scar. It is the most aggressive and, fortunately, least common, subtype of BCC. Another type is the Pinkus type, also known as fibroepithelioma. It is distinguished by its unique reticulated appearance on histology. The Pinkus type of BCC is most frequently found in the lumbrosacral area.

With what can basal cell carcinoma be confused?

Nodular BCC can resemble squamous cell carcinoma, non-pigmented nevus, molluscum contagiosum, and sebaceous hyperplasia. Pigmented BCC can be confused with other pigmented lesions such as pigmented nevus and, importantly,malignant melanoma. Seborrheic keratosis is also in the differential. Superficial BCC can be confused with eczema,dermatitis, psoriasis, and Bowen’s disease. Scarring BCC, as the name suggests, can be confused with a scar or sometimes a squamous cell carcinoma.

How is basal cell carcinoma diagnosed?

A BCC might be suspected after a routine skin exam. A new growth that does not heal and bleeds easily is suspicious for BCC, especially in fair skinned persons with a history of sun exposure and evidence of actinic (sun) damage. This suspicion will be confirmed with a skin biopsy, either punch or shave, which is interpreted by a dermatopathologist. As the cancer’s name suggests, its cells resemble the basal cells of the epidermis. The tumor extends from the epidermis into the dermis with various morphologies such as nodules, cysts, buds, and strands.

How is basal cell carcinoma treated?

Possibilities include scalpel excision, curettage and electrodessication, cryotherapy, radiation therapy, and 5-fluorouracil, a topical chemotherapeutic agent. Treatment depends on various parameters such as size, location, whether it is a recurrence, histopathologic type, and age and general health of the patient. Excision with suture closure is the most common modality. A special form of surgery, Mohs’ micrographic surgery, is sometimes performed. In this procedure, the surgeon examines the excised tissue in real time to ensure that it is free of cancerous cells. It enables the surgeon to remove only as much tissue as is necessary to ensure tumor-free margins.

What is the prognosis for basal cell carcinoma?

These tumors rarely metastasize (spread to a remote location), with an estimated rate of 0.003%. However, they can be aggressive locally. If not treated in a timely fashion, a BCC can result in significant deformity. Annual follow-up is recommended; up to 35% of patients will develop a second BCC within five years.

How is basal cell carcinoma prevented?

Avoidance of further sun damage is critical. This includes the daily use of sunscreens with a minimum SPF of 15 to 30, depending on skin type, protective clothing such as a wide-brimmed hat and long sleeved shirt, and sun avoidance, especially midday when the sun is strongest.

More about basal cell carcinoma

Image links

DermNetNZ: Fact Sheet and Photos of Basal Cell Carcinoma

Other useful links

The Skin Cancer Foundation: Basal Cell Carcinoma
Ramsey, ML. Basal Cell Carcinoma. e-medicine. May 9, 2006

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Skin Cancer

About skin cancer

Skin cancer is the most common malignancy.  There are three major varieties:

-Basal cell carconoma

-Squamous cell carconoma


These are discussed in separate entries.

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