There are four major clinical subtypes of cutaneous melanoma: melanoma extensively in surface (70%) which occurs more often in women on their inferior members and to men on the body, it is met more frequently to the persons in the middle age, with longer evolving; nodular melanoma (15%); lentigo malignant melanoma (10%), lentiginous acral melanoma (5%).
Nodular melanoma is the most aggressive melanoma type. It usually appears as a small, round nodule, with a smooth border. Most of them are black, although some may be brown, blue, gray or red. Since this type of cancer spreads rapidly, is often diagnosed when it is to an advanced stage. Nodular melanoma - is usually black and can grow quite quickly;
Clinically there are two major types of melanoma:
In the superficial melanoma the peripheral invasion surface is greater, with typical and atypical frequent mitoses, with or without lymphocytic infiltration and fibro-vascular nodular melanoma invasion. In nodular melanoma the dermal invasion is in block and the peripheral one is in epidermis and limited to the edge of the tumor.
Malign melanoma can occur in any area of the body, with short evolution and debut nodular form. Its uniform color is dark blue or gray and net limits. In its evolution may become polypoid - a sign of very bad prognostic.
Surgical excision should be adapted after the clinical form of the tumor; excision of nodular tumors needs to be more aggressive compared to the lentigo melantics ones.
Removal of lymph node stations have to be taken into consideration to the patients with nodular form of melanoma, in those with tumors over 1.5 mm thick, ulcerated tumors and those in which the tumor is located at the head, neck, back (especially men which have a more reserved prognosis).
The conversion of moles in melanoma is significantly less common than melanoma with spontaneous appearance. The congenital mole, especially if it grows more than 2 inches in diameter, is likely to turn into malignant melanomas. A mole that grows, changes its appearance or color, bleeds, itches, must be removed preventively. This removal is never the cause of cancer appearance.
The evolution of a malignant melanoma remains severe, given the greater tendency to relapse and metastasis. The surgical removal of a malignant melanoma is essential.
Cancer chemotherapy is used in case of recurrence or metastases. Prevention consists of information on solar radiation hazards, of using the sun creams and in the early detection of this disease in susceptible subjects.
In nodular melanoma, tumors developed either in a junctional nevus, or "de novo", without an underlying lesion.
Nodular melanoma as well as the lentigo malignant melanoma and the extensive pagetoid melanoma, presents a junctional activity. Unlike the other two types of melanoma, in the nodular melanoma, the junctional activity does not exceed the tumor and does not contain the peritumoral epidermis. In contrast to the development of the lentigo malignant melanoma and pagetoid melanoma, in which we distinguish a first period of horizontal extension, followed by vertical extension with the dermis invasion, the nodular melanoma develops from the beginning only in the vertical way, invasive in depth.
Characteristic for this type of melanoma is the separation from the epidermis of the isolated melanocytes by vast distances, clustering in nests being rare and sometimes just outlined. The migration of melanocytes occurs simultaneously, along with keratinocytes, to the surface of the epidermis till the corneum stratum. The tumor is full of cells, with reduced stroma. Most often, the cells are of epithelioid type, but spindle cells may be also found, balloon cells, giant cells and cubic cells. The nuclear atypia are very numerous and very varied.
Tumor cells are arranged in the form of nests, beaches, islands or cords. Regarding the histological type of tumor, the nodular melanoma has a worse prognosis than melanoma with superficial extension, being frequently associated with metastatic adenopathy.