Sentinel node biopsy in melanoma patients: dynamic lymphoscintigraphy followed by intraoperative gamma probe and vital dye guidance.

Biopsy of the first tumor-draining lymph node (sentinel node, SN) is bound to become the procedure of choice in regional staging of melanoma patients. A tumor-negative SN virtually excludes lymphatic metastases and obviates the need for lymph node dissection. The aim of this study was to combine the advantages of three known techniques to improve the yield of successful SN biopsies. A total of 150 drainage areas in 135 patients was evaluated. First, preoperative dynamic and static lymphoscintigraphy was performed after injection of technetium 99m colloidal albumin. In all patients one to three focal accumulations, concordant with SNs, were seen in the lymphatic drainage areas, in 97% within 20 minutes from injection of the tracer. Peroperative identification of the SN, 2 to 24 hours after injection of the tracer, was done with a handheld gamma probe to estimate the optimal site for the small incision and to guide preparation. Vital dye was injected just preoperatively and served to facilitate the final identification and biopsy of the SN. A total of 216 SNs were biopsied. Micrometastases were found in 39 SNs in 30 drainage areas, and in 22 of the 30 of the SN was the only node harboring tumor. In 5 of 30 drainage areas, the SN did not contain blue dye and would not have been found without the gamma probe. Up to now (follow-up 233-691 days) no recurrence has developed in the lymphatic drainage areas where the SN was tumor-free. It was concluded that by combining these three techniques the SN could be detected and excised in all patients. The procedure combines a steep learning curve with high sensitivity.

Invasion of laryngeal cartilage by cancer: comparison of CT and MR imaging.

Forty-two patients with laryngeal carcinomas were examined with computed tomography (CT) and magnetic resonance (MR) imaging. The accuracy of both CT and MR imaging in the depiction of cartilage invasion was evaluated in 16 patients by comparing findings at CT and MR with pathologic findings. Calcified cartilage that has been invaded by cancer is frequently seen on CT scans as having an intact contour. Tumor approaching nonossified cartilage may simulate cartilage invasion. On T1-weighted MR images, invaded marrow of ossified cartilage is of intermediate signal intensity, allowing it to be differentiated from normal bone marrow. On proton-density images, tumor is of increased signal intensity, which allows it to be differentiated from nonossified cartilage. In our experience, the specificities of CT and MR imaging were approximately equal (91% and 88%, respectively), but CT had a considerably lower sensitivity than MR (46% vs. 89%). Gross movement artifacts, which resulted in nondiagnostic images, occurred in 16% of the MR examinations. MR imaging is recommended as the modality of choice in the diagnosis of cartilage invasion.