Malignant Melanoma, Classification And Diagnosis

Malignant melanoma, classification and diagnosis

Malignant melanoma classification

Surface extension melanoma

Specifically in this pathology, surface extension melanoma becomes the most frequent type, with approximately 70% of all cases worldwide. Recent studies has already been shown that not only affects patients with risk factors associated with age but also affects between the fourth and fifth decades of life, it will also be located in lower extremities and in the trunk of people without any distinctionof age, in addition to some areas of discontinuous sun exposure but intense. In the beginning we will have a small blackish brown lesion or you can also see a bluish focal discoloration, which will progressively increase in radial shape. In the invasive vertical growth phase it occurs when reaching a diameter of 2.5 cm, after months or years of evolution and this is interpreted clinically by the appearance of a nodule.

Nodular melanoma

This subtype will have as a basic concept to join approximately 15% of cases. It usually occurs with greater repetition when the person is between 50 and 60 years of life, and is associated with lower extremities and trunk. When the injury is blackish or bluish as it was already explained it is very common to confuse it with a hemangioma or a bruise. Subsequently it progresses very quickly until that same lesion forms one more but with more nodular characteristics characterized by a homogeneous color between red, blue, blackish, violet or ribbed.

This type of injury described frequently manages to ulce. The lesions invade the lymphatic vessels and blood vessels, therefore their dissemination is at a distance, and could metasize towards any organ.

Malignant lentigo melanoma

This subtype is the least common of all and will represent only 5% of all forms, it has been demonstrated that its establishment and origin from a precursing injury have been very frequent. To patients who have an advanced age between 55 and 70 years, it is able to affect localized and exposed areas that reveal actinic damage as in the extension of the forearms, the face, the neck, and the hands, where we already know that they are placesChronic sun exposure. The type presented is the least aggressive and that has a great evolution precisely before metastaging and growing radial and subsequent vertically with an appearance of a macular -shaped nodule and regularly on high.

Acral lentiginous melanoma

As for the percentage of this subtype, it covers 10% of all those already presented and specifically found a greater incidence in the east race, black race and mestizos since the radial component was found as predominant unlike the white tests. The characteristic of these lesions are hyperpigmented macules are of irregular edges and commonly blue or black or the combination of these two;Quite occasionally, nodules are developed and progress to ulcers and finally bleed, the most frequent location is in palms, plants and subungual with greater regular in the thumb in addition to mucous membranes and in male sex a predominance of penis. It is more common to find it in men than in women with a frequency of (3: 1). When the vertical phase begins, the appearance of papules, nodules and destruction of the nails is already noticeable, there is also the sign of Hutchinson that refers to dark brown hyperpigmentation throughout the nail and adjacent skin.

Mucous melanoma

As for oral melanoma, the diagnosis is sought to take into account three main criteria since it is a very rare tumor that constitutes about 4% of all melanomas, therefore there has to be histological demonstration and especially clinic associated with presenceof intraepidermal activity, preponderantly the impossibility of demonstrating another primary place. It usually appears between the sixth and seventh decade of life. In vaginal mucosa his behavior is aggressive since at the time of diagnosis his aggressiveness is 85%.

Aerodigestive tract melanomas

They are associated with 30 – 37% of pre -existing injuries. Its most frequent location is the palate and mucosa associated with trauma in older people who use prostheses, it has also been demonstrated to chemical factors (tobacco and alcohol) and poor oral hygiene, but they are still being demonstrated.

Ocular melanoma

Its main origin is in the choroid and the ciliary body. The removal of the ocular globe that is affected could spread that the disease spreads in the form of very difficult diagnostic metastasis that become clinically silent undetectables called silent because they can progress without showing any observable evidence until they progress and just become diagnosed. The most recurrent extraocular metastases found are liver and lead to hepatomegallic syndromes including jaundice and glass eye clinical picture.

Epidemiology of malignant melanoma

According to WHO, 160,000 new cases have appeared every year in the world of malignant melanoma, which has caused that in total the number of cases to double for every 10 to 20 years;It is also estimated that there are just over 57,000 deaths that are related to this pathology annually.

In recent years it was recorded that the greatest incidence was perceived in women with about 81 134 new cases, with respect to men who regified an incidence of 79 043 new cases (male/woman/woman relationship.97). According to Globocán, this registry of new cases of malignant cutaneous melanoma in 2018 worldwide was 258723 new cases translated to 1.6% (13)

In our country in the Metropolitan Lima Cancer Registry (RCLM), it occupied the 20th place of all cancers with 192 cases registered in 2016. What represents 1.3% of the total cancer occupying the twenty place. (10)

Malignant melanoma stag

Melanoma clinical stages:

Stage 0 Melanoma (melanoma in situ)

It will refer to an injury that fails to be invasive for the dermis, with low metastatic potential and a great forecast. A margin of surgical split for melanoma in situ 5 mm is considered acceptable in the opinion of consensus in the current guidelines.

Clinical stage I and II

The two tumor primary variables that manage to influence the early stage of localized melanomas are closely related to the prognosis and are those with the thickness of the tumor or depth. and the state of ulceration, in thin melanomas (≤ 1.00 mm or T1), the mitotic tumor index enters as an important additional variable in the current classification system, replacing the Clark level in the old classification system.

The presence of ulceration generates a modification of "B" in stadium T, the survival associated with when the patient is 10 years with melanomas T1 and their approximately 92% percentage, compared to the other 50% of patients with melanomas T4 T4. Likewise, the appearance of ulcers is a strong and very important predictor in patients who have melanoma with a survival rate of approximately five years with a value of 71% in T4A comparing the T4B melanomas that have 53%.

The mitotic rate associated with this tumor has also been recognized as an important prognostic factor in patients with clinically located melanom. When the mitotic index is taken into account, the Clark level loses its meaning in T1 lesions and therefore its use is recommended only if the mitotic index information is not available for an injury.

Among non -ulcerated melanomas, the 10 -year survival rate is 95% in lesions with mitotic index less than 1/mm2 compared to 88% in those with mitotic index greater than or equal to 1/mm2.

Clinical Stadium III

The disease in transit or satellitosis (any disease N> 0) stage III is defined by the presence of regional metastasis in the form of ganglionic metastases.

The determinants of stage N should include the number of affected lymph nodes, if there are micrometastasis or macrometastasis, presence of disease in transit or satellitosis and concomitant node disease. The group for the stage of the disease in stage III is also affected by the presence of ulceration in the primary tumor (which makes the scenario at least IIIB). Among patients in stage III there is significant heterogeneity in the five -year survival forecast, which goes from 70% in patients with primary melanomes not ulcerated with a single node with 39% micromethastasis in patients with metastatic lymph nodes with disease in transit or transit diseaseConcomitant satellitosis (N3).

Clinical Stadium IV

The disease in this stage is defined by the presence of distance metastasis and is subclassified between:

M1, is in turn classified as a decreasing prognosis in:

• M1A Distant, subcutaneous or ganglionic skin.

• M1B pulmonary metastasis or M1C, other non -pulmonary visceral metastases or any remote metastasis with a high level of dehydrogenase lactate.

Diagnosis of malignant melanoma

All studies that are done to the patient must be based on their clinic and the type of statification in which it corresponds. With regard to stages in which we can locate the possibility of suffering the disease as a genetic antecedent, whether ganglion or systemic. As for the diagnostic method used by the biopsy technique by incision in some injury, which can be a malignant melanoma is still a reason for innumerable controversies because some studies affirm that this procedure could cause metastatic sowing.

The curettage and shaving biopsy are completely contraindicated in any patient since the material we manage to obtain will not determine the depth of impregnation of the tumor, this data is fundamental and extremely important to consider an adequate therapy and a favorable prognosis. As for studies with immunohistology and the already known molecular techniques today they are very important decisions since when evaluating each patient by individual and using these innovative techniques they will allow us to reach a more accurate forecast.