Detection of regional melanoma metastases by ultrasound B-scan, cytology or tyrosinase RT-PCR of fine-needle aspirates

Physical examination and ultrasound B-scan screening are important follow-u p procedures in melanoma patients with regional disease. However, they do n ot allow definite diagnosis of suspicious lesions. Fine-needle aspiration c ytology (FNAC) enhances the diagnostic accuracy in such patients but, unfor tunately, reaches its technical limits, particularly when very small or nec rotic lesions are examined;We therefore tested whether tyrosinase reverse t ranscription polymerase chain reaction (RT-PCR) of fine-needle aspirates (F NA-PGR) could help to increase diagnostic sensitivity. With clinical follow -up in 69 melanoma patients 81 regional lymph nodes were detected by ultras ound B- scan examination, nine of whom appeared to be palpable. Technically FNAC was successful in ail 81 lymph nodes, while FNA-PCR failed to obtain RNA at detectable levels in two lymph nodes of two patients. Of 79 lesions which have been completely evaluated by B-scan, FNAC and FNA-PCR, 44 proved to be melanoma metastases by histopathology,while the remaining 35 lesions were finally classified as non-specific lymph nodes. Of the 44 melanoma me tastases 80% (n = 35) have been detected by B-scan, 90% (n = 39) by FNAC an d 100% (n = 44) by FNA-PCR (P < 0.05 vs FNAC, P< 0.005 vs B-scan). In the s ubclass of lesions with diameters below 10 mm the sensitivities were 72% (n = 13), 78% (n = 14)and 100% (n = 18) respectively In 35 regional lymph nod es classified as benign lesions, FNAC was always negative while FNA-PGR pro duced one positive result. Neither of these methods did produce false posit ive results in 15 control lymph nodes of non-melanoma patients. We conclude , that FNA-PCR might have superior sensitivity as compared to FNAC or ultra sound B-scan, particularly in melanoma lesions with diameters below 10 mm.