Lymphoscintigraphy in the study of lymphatic drainage patterns in patientswith melanoma

BACKGROUND: In order to plan the pertinent surgical technique for each pati ent with melanoma or other skin malignancies, it is mandatory to identify t hose lymphatic basins at risk for metastases. The advent of radiotracers fo r functional studies of the cutaneous lymphatic system during the last deca de has resulted in the disclosure of an unexpected interindividual variabil ity of the lymphatic drainage in both head and neck and trunk. OBJECTIVE: To ascertain the usefulness of lymphoscintigraphy for depicting the cutaneous lymphatic draining basins in patients with primary melanoma o f the head, trunk and limbs, and to compare the observed lymphatic drain wi th the expected pattern of lymph flow according to the classical anatomical studies. MATERIAL AND METHODS: Prospective study in a univertsity hospital (Barcelon es Nord area). Consecutive patients with the diagnosis of cutaneous melanom a were recruited after excisional biopsy of the primary tumor. Every patien t was intradermally injected with rhenium-sulfide colloids or colloidal tec hnetium labelled with Tc-99m in four quadrant doses of 0.3 mi around the le sions or its excisional scar. Scintigraphic imaging of the migrating radiot racer resulted in a flow pattern that was compared with its <<classical>> e xpected counterpart. RESULTS: Althogether, 55 lesions were studied, including 9 in the head, 21 in the trunk and 25 in the limbs (7 upper and 18 lower). The scintigraphic drain pattern did not match the expected classical pattern in 37,0% of the lesions overall (14% upper limbs, 42% truncal lesions out from an area 2.5 cm at both sides of Sapey's line or the midline, 16,6% lower limbs and 89% head and neck). CONCLUSIONS: Lymphatic drain of the skin shows a very high intrapersonal va riability leading to the need for an individual work-up in order to know th e lymphatic basins at risk for metastases. The high rate of unexpected or n on-matching patterns casts some doubts over those previous studies that did not include lymphoscintigraphy on a patient-basis.