Melanoma is a malignant tumor of the pigment cells of the skin. It appears in various forms one of which is nodular melanoma. This type of melanoma is characterized by so called vertical growth. Namely, it starts to develop in the skin, and then penetrates deep into the tissues beneath the skin. It is known by its high malignancy and very fast development.
Nodular Melanoma Stages
There are several staging systems for melanoma – Clark scale, Breslow scale, TNM staging, and numeric staging. The Clark scale is most frequently used for nodular melanoma. This scale tells us how deep the tumor has got on its way towards deep tissues. There are 5 Clark’s levels:
- Level 1 (melanoma in situ) – the tumor affects only the superficial layer of the skin called epidermis.
- Level 2 – melanoma cells have ruptured the epidermis, but still didn’t get to the next layer
- Level 3 – melanoma has infiltrated the layer of the skin called papillary dermis
- Level 4 – melanoma has gone even deeper and penetrated into the reticular dermis
- Level 5 – melanoma has affected the fat tissue located under the skin.
The Breslow scale is used by pathologists, and it measures the thickness of melanoma, and TNM staging is taking into consideration the existence of regional and distant metastases as well. Numerical scale is a combination of these previous methods and it has following stages: 0 (melanoma in situ), 1A, 1B, 2A, 2B, 2C, 3A, 3B, 3C, 4.
Nodular Melanoma Symptoms
Nodular melanoma can affect any area of the skin, but it is most commonly presented on head and neck. It is appearing as a small, round lump, which is growing very fast during the next several weeks. Fast growing lump, especially if it is pigmented on any part of the body can be suspicious to nodular melanoma. At the time of diagnosis, it is usually larger than 1 cm. In two third of all cases, nodular melanoma is pigmented, but the lesion without pigmentation does not exclude this diagnosis. It can have rough or smooth surface, but it is usually symmetrical. Sometimes, the areas of ulceration and bleeding can appear, and that is a very bad sign which contributes to diagnosis of nodular melanoma. Some patients report itchiness in the place of melanoma.
Nodular Melanoma Treatment
The standard treatment for all types of melanoma is a surgical resection of the tumor. To be sure that the entire tumor is removed, surgeons always remove a 2 – 3 cm wide ring of healthy tissue around the tumor. Nodular melanoma treatment should be performed with great precision because of the nature of the tumor to penetrate the deep tissues. Actually, there are recommendations on how much of surrounding tissue should be removed in order to minimize the chances for returning of nodular melanoma.
After the surgery, the removed nodular melanoma is examined by pathologist in order to confirm the diagnosis and check whether the entire tumor was removed. If the nodular melanoma has deeply penetrated, it is not possible to remove it during the initial surgery. Therefore, additional operations are needed as well as courses of radiotherapy. The high resistance of melanoma to radiotherapy causes the need for very high doses of radiation to be applied on tumor cells.
Nodular Melanoma Survival Rates
There are many factors that influence the nodular melanoma survival rates. It has been shown that the most important of them is the thickness of the tumor at the time of initial removal. The occurrence of metastases is very rare if the tumor thickness is less than 0.75mm. Melanomas of thickness 0.75 – 1mm give metastases in 5% of cases. The bad thing is that the probability of the existence of metastases rises very rapidly with further increase of tumor thickness. Therefore, melanomas of thickness >4mm give metastases in 40% of cases.
Nodular Melanoma Prognosis
So the prognosis of nodular melanoma, as well as survival rates, depends mostly on tumor thickness at the time of surgical removal. Melanoma in general is one of the most unpredictable malignancies in human pathology. Therefore, it is better to speak about probabilities of certain outcome than about strict prognosis. After the initial treatment of the tumor, a follow-up of every patient is necessary, for the next five years to eliminate the possibility of returning tumor. In 5 – 10 % of patients, melanoma appears again in the same place, but in 20% it appears in a new place on the body as a nodular melanoma in situ. Patients should be educated to perform self – examinations and to visit their health care provider in agreed time. The doctor should then check if there are any changes in the place of initial nodular melanoma, palpate regional lymph nodes, and perform a complete examination in order to be sure that the patient is fully recovered.
1. Richardson et al. The incidence and thickness of cutaneous malignant melanoma in New Zealand 1994–2004. NZ Med J 2008;121:1279
2. Mar, V., Roberts, H., Wolfe, R., English, D.R., Kelly, J.W. Nodular melanoma: a distinct clinical entity and the largest contributor to melanoma deaths in Victoria, Australia. J Am Acad Dermatol. 2013 Apr;68(4):568-75