Detection of recurrent malignant melanoma with 99mTc-MIBI scintigraphy

Initial reports suggest that 99mTc-methoxyisobutylisonitrile (MIBI) scanning may be of clinical value in staging patients with malignant melanoma. We carried out a study to evaluate the potential of this technique in the detection of recurrent disease. Whole-body 99mTC-MIBI scans were performed in 81 patients with a history of a surgically excised MM: 28 with known recurrent lesions and 53 during follow-up without evidence of disease. Images started 10 min post-injection, using a dose of 740 MBq. Diagnoses were confirmed by cytological/histological examination or at least one conventional imaging modality. Blinded interpretations of the MIBI scans were performed. Whole-body MIBI scanning correctly detected 68 (92%) of 74 metastatic lesions in the following sites: regional lymph nodes (n=23), non-regional lymph nodes (n=10), skin (n=16), brain/cerebellum (n=6), lung (n=8), bone (n=4) and breast (n=1). The technique failed to detect three subcutaneous regressive lesions (< 1 cm), one liver metastasis, one spleen metastasis and a case of multiple small lesions of the duodenal mucous membrane. In 14 patients the procedure detected previously unknown metastatic lesions. These results suggest that 99mTc-MIBI scanning is an effective imaging modality for whole-body screening of metastatic disease in malignant melanoma patients with the potential to influence treatment planning.