Lentiginous melanoma

What is lentiginous? melanoma?

Lentiginous melanoma is a slow progressive A variant of melanoma found on sun-damaged skin of the trunk and limbs.

Lentiginous melanoma is usually diagnosed when the evil one the cells are in the place and is believed to have a low risk of invader melanoma. This type of melanoma has recently been classified as distinct from superficial spreading melanoma and lentigo malignant (melanoma).

Who Gets Lentiginous Melanoma?

Lentiginous melanoma risk is related to sun damage. Therefore, lentiginous melanoma is more common in outdoor workers, in older people, and in association with sun damage and non-melanoma skin. Cancer. Although it often occurs in those with very fair skin (skin phototype 1 and 2), it can also occur in those who tan quite easily (phototype 3). It is rare in brown or black skin (phototype 4–6).

Lentiginous melanoma has been more common in men than women in most reports. Most patients with lentigo maligna are older than 40 years, and the maximum age of diagnosis is between 60 and 80 years.

Unlike superficially spreading melanoma, lentigo maligna is not related to the amount of melanocytic naevi (moles) or atypical naevi.

What does lentiginous melanoma look like?

Lentiginous melanoma presents as a slow growth or change patch discolored skin. At first, it often looks like common freckles or brown marks (lentigines) It becomes more distinctive over time, often growing several inches over several years or even decades. Like other flat forms of melanoma, it can be recognized by the ABCDE rule: asymmetry, edge irregularity, color variation, large diameter and evolution.

The characteristics of lentiginous melanoma include:

• Large size:> 6 mm and often several centimeters in diameter at the time of diagnosis.
• Irregular shape
• Variable pigmentation - colors can include tan or light brown, dark brown, pink, red or white
• Smooth surface.
• Location on trunk and extremities

The following features are highly suspicious for invasive melanoma.

• Thickening of part of the injury
• Increasing number of colors, especially blue or black.
• Ulceration or bleeding
• Itching or itching

What Causes Lentiginous Melanoma?

Lentiginous melanoma is a proliferation of evil pigment cells (melanocytes) along the basal cap of the epidermis. The precursor lesion is an atypical solar lentigo or a lentigo / junction nevus. It is unknown what causes the cells to become malignant, but genetic mutations it can begin within primitive stem cells.

Sun damage results in a degree of immune tolerance, allowing abnormal cells to grow out of control.

What tests should be done?

Accurate diagnosis of lentiginous melanoma is essential. Clinical diagnosis is assisted by dermoscopy and in some centers, by confocal microscopy.

No other tests are necessary in most patients, but those with invasive melanoma that is more than 1 mm thick may be recommended to have imaging studies. lymph node biopsy and blood tests.

New tests are being developed to determine specific gene mutations with lentiginous melanoma, which may inform the future targeted therapy.

Dermoscopy

Dermoscopy (also called dermoscopy), or the use of a dermatoscope, by a dermatologist or another physician trained in its use, it can be very helpful in distinguishing lentiginous melanoma from other types of skin lesions. However, the dermoscopic appearance of early lentiginous melanoma can be difficult to distinguish from others. pigmented lesions, particularly lentiginous nevi of the elderly.

• Melanocytic nevi (moles)
• Solar lentigos
• Pigmented actinic keratosis
• Seborrheic keratosis

Diagnosis excision

If a skin lesion is clinically suspicious for lentigo maligna, it is best to cut it (excisional biopsy) with a 2-3 mm margin. Partial biopsy is less accurate than full excisional biopsy, since a single small biopsy could miss a malignant focus.

The pathological diagnosis of melanoma and its precursors can be very difficult. Some clinically typical lesions of lentiginous melanoma are reported to show only nests of attachment melanocytes, others have criteria to diagnose in the place melanoma, and some show invasive cancer.

the histological Features of lentiginous melanoma include epidermal hyperplasia (as in the solar lentigo), focal atypical melanocyte attachment nests and may include pagetoid spread (individual melanocytes within the upper areas of the epidermis). Lentiginous melanoma can be difficult to distinguish from atypical lentiginous junctional nevus, in which the architecture and cytology atypia it is less severe and the pagetoid extension is absent.

Pathology report

the pathologistThe report should include a macroscopic description of the specimen and melanoma (naked eye view), and a microscopic description. The following characteristics should be reported if there is invasive melanoma.

• Diagnosis of primary melanoma
• Breslow thickness to the nearest 0.1 mm
• Clark's invasion level
• Excision margins, that is, normal tissue around the tumor
• Mitotic rate - a measure of how fast cells are proliferating
• Whether or not there is ulceration

The report may also include comments on the cell type and its growth pattern, invasion of blood vessels or nerves, inflammatory reply, regression and if there is an associated in situ disease.

What is the thickness of Breslow?

Breslow thickness is reported for invasive melanomas. It is measured vertically in millimeters from the top of the granular layer (or base of superficial ulceration) to the deepest point of tumor involvement. It is a strong predictor of results; the thicker the melanoma, the more likely it is that metastasis (spread).

What is Clark's level of invasion?

Clark's level indicates the anatomical plane of the invasion.

The deeper the Clark level, the greater the risk of metastasis (secondary propagation). It is useful for predicting the outcome for thin tumors, and less useful for thick ones compared to the Breslow thickness value.

What is the treatment for lentiginous melanoma?

Lentiginous melanoma must undergo surgical excision. This means cutting it off and repairing the defect. This may be simply by closing the wound and stitching it together, but when this is difficult, it may be necessary to create a flap or skin graft. These latter procedures may be delayed for a few days while waiting for the histopathology report to confirm that the melanoma has been completely removed.

A second procedure is often organized to remove a margin of healthy tissue based on whether it remains in situ (5–10 mm) or has become invasive (10–20 mm or more).

Staging

Staging melanoma means finding out if melanoma has spread from its original place on the skin. Most melanoma specialists refer to the American Joint Committee on Cancer (AJCC) cutaneous melanoma staging guidelines (2009). In essence, the stages are:

What is the outlook?

Lentiginous melanoma in situ is not dangerous; It only becomes life threatening if an invasive melanoma develops within it.

Long-term follow-up involves reviewing the treated area and a complete skin examination to identify new worrisome lesions. If the injury was invasive, the regional lymph nodes should also be examined. It may be prudent to biopsy any lesions that arise in or near the excision site.

The risk of spread (metastatic melanoma) of invasive melanoma depends on several factors, but the main one is the thickness of the melanoma at the time of its surgical removal.

The Australian and New Zealand Melanoma Guidelines (2008) report that metastases are rare for 4mm melanomas resulting in a 10-year survival of around 50%, according to statistics from the American Joint Committee on Cancer (AJCC).