Feasibility of preoperative lymphoscintigraphy for identification of sentinel lymph nodes in patients with conjunctival and periocular skin malignancies

Purpose: To determine the feasibility of preoperative lymphoscintigraphy for identification of sentinel lymph nodes (SLNs) in patients with conjunctival and periocular skin tumors and to determine the patterns of lymphatic drainage from such tumors. Methods: We retrospectively reviewed the records of all patients with bio-psyconfirmed conjunctival and periocular skin malignancies who underwent lymphoscintigraphy with or without SLN biopsy between January 1999 and June 2000. Patients underwent lymphoscintigraphy with 0.3 to 1 mCi of technetium Tc-99m sulfur colloid in a volume of either 0.2 mL or I mL. Images were taken as soon as the first SLNs were detected through the camera and every 15 minutes thereafter. Intraoperative mapping and SLN biopsy was performed I to 2 days after lymphoscintigraphy unless the patient refused or there were medical contraindications to the procedure. Results: The study included 7 patients with malignant melanoma of the conjunctiva or periocular skin and I patient with Merkel cell carcinoma of the eyelid. On lymphoscintigraphy, at least I SLN was identified in 7 of the 8 patients. Although all lesions located in the lateral half of the ocular adnexa drained to at least one SLN in the parotid (preauricular) area, there was some variability in the drainage patterns of lesions located in the medial half of the ocular adnexa. A smaller injection volume (0.2 mL) was adequate for detecting the nodes draining the area of injection and led to less spread of technetium to the surrounding areas. Six patients underwent SLN biopsy. In all but one, the nodes identified during surgery corresponded with those visualized on lymphoscintigraphy. Conclusions: Preoperative lymphoscintigraphy successfully identifies SLNs in most patients with conjunctival and periocular skin malignancies. Smaller injection volumes (0.2 mL) appear to be adequate for identification of the sentinel nodes and lead to less spread to surrounding tissues.