[Fine needle aspiration cytology of metastatic malignant melanoma. Improvement of results with ultrasound control].

A review of 315 fine-needle aspiration cytologies (FNAC) carried out from 1984 through 1992 in 157 patients with suspected metastatic melanoma was carried out: 176 results were confirmed by histological examination and 139 by clinical follow-up. In the first period, from 1984 through 1988, we observed 5 false-negative results out of 123 evaluable FNACs. All were caused by technical failure. In the second period, from 1988 through 1992, all fine-needle biopsies of impalpable masses were done with ultrasound guidance. Thus, we were able to avoid further false-negative results. No errors in interpretation were found. We obtained 219 true-positive and 91 true-negative results with 97.8% sensitivity, 100% specificity, 98.4% accuracy, 100% positive and 94.8% negative predictive value. In 3 cases with metastatic melanoma the cytological diagnosis only was 'malignant tumor', while in another 5 patients the cytodiagnosis of melanoma was not definitive. Immunocytology was helpful in these cases in identifying melanoma. FNAC allowed the correct diagnosis of a second malignancy in 4 cases (one papillary thyroid cancer, one Hodgkin's disease, two non-Hodgkin's lymphomas). No complications occurred. In our opinion, FNAC--for poorly defined lesions with ultrasound guidance--is a very rapid, safe and accurate method that allows reliable diagnosis of metastatic melanoma.