staging system for melamoma

17. What is the TNM staging system for melamoma?

The TNM (primary tumor, regional nodes, metastasis) staging system is the most comprehensive classification of melanoma. Using established risk factors for advanced disease, it stratifies patients based on the thickness of the melanoma, ulceration, micrometastases or nodal metastastes, and distant metastatic disease. Recently revised, it more accurately predicts prognosis and the need for further treatment.

18. What are the chances of nodal and systemic spread of the various degrees of melanoma invasion?

Regional node metastases occur in about 2% of melanomas < 0.76 mm in depth; the distant spread approaches 0%. In tumors 0.76-1.5 mm thick, nodes are cancerous in 25% and distant spread is 8%. In tumors 1.5-4.0 mm thick, node metastasis occurs in 57% and distant spread in 15%. In tumors > 4 mm, node metastasis occurs in ≤ 62% and distant spread is about 72%.

19. What are the characteristics of a subungual melanoma?

Subungual lesions are often mistaken for a chronic inflammatory process; therefore, most patients present quite late. They are usually older than patients with other forms of cutaneous melanoma. The great toe is the most common site of origin. Amputation at or proximal to the metatarsal phalangeal joint and regional sentinel lymph node biopsy are advised by most authors. The primary lesions are usually deeply invasive, and the lymph nodes are positive for cancer in the majority of cases, either at the time of the original diagnosis or at subsequent follow-up.

20. Describe the technique of sentinal lymph node (SLN) biopsy.

The SLN biopsy is based on the theory that lymph from a solid neoplasm initially drains to a central, culprit sentinel node (SN). These SNs are the first nodes at risk for metastatic disease. The nodes can be biopsied and examined with serial sectioning and immunohistochemical staining. The SLN identification technique requires the cooperation of a surgeon, radiologist, and pathologist. Lymphoscintigraphy with the injection of radioactive technetium sulfur colloid (99mTeSC) is performed around the site of the primary melanoma. Scans are then performed in 15 minutes. The SLN is located and the overlying skin is marked. Four hours later, the patient is taken to the operating room for intradermal injection of blue contrast dye (lymphazurin 1%) around the primary site. A hand-held gamma probe identifies the hot spot, and a small incision is made over this area for removal of the SLN. A combination of blue contrast dye and radiocolloid provides the highest yield of SN identification