Lymphatic Drainage in Patients with Primary Cutaneous Melanoma - the Role of Lymphoscintigraphy in Sentinel Lymph Node Biopsy

Lymphatic drainage of the skin is highly variable from patient to patient and unexpected patterns of lymph drainage are not uncommon. Drainage can occur from the skin of the back through the posterior body wall to nodes in the retro-peritoneal, paravertebral and para-aortic areas. Drainage from the skin of the back to nodes in the triangular intermuscular space occurs in 10% of back melanomas and drainage from the back over the shoulders to SLNs in the neck is seen in 20% of patients. In the head and neck lymph drainage can occur up the neck from the base to nodes in the occipital and upper cervical regions and drainage can occur from high on the scalp directly to nodes in the supraclavicular fossa completely bypassing nodes higher in the neck. Lymphatic drainage is common across the midline to contralateral SLNs and interval nodes are seen as SLNs in 7% of patients with melanoma. For SLN biopsy to be accurate high quality lymphoscintigraphy is vital to ensure that all SLNs are biopsied in every patient regardless of their location.