Fine aspiration versus fine cutting needle, and comparison between smear cytology, inclusion cytology and microhistology in abdominal lesions.

Two hundred patients underwent ultrasound guided percutaneous fine needle biopsy of focal solid abdominal lesions using 22 gauge aspiration and cutting needles. The material obtained by aspiration needle was treated by smear cytology and by inclusion cytology, and that obtained by cutting needle by microhistology. The retrieval rate was 89% for aspiration needle (smear cytology = 89%, inclusion cytology = 83.5%) and was 83% for cutting needle; the combined diagnostic accuracy was 98%. The typing accuracy was 76% for smear cytology, and was 84% for inclusion cytology and microhistology. We conclude that: 1. to obtain the highest retrieval rate (98%) both aspiration and cutting needles are necessary, because the aspiration needle is more likely to secure necrotic or soft tissue, and the cutting needle, fibrous or hard tissue; 2. histologic treatment of the samples yields a higher typing accuracy: 84% vs 76%; however, smear cytology remains essential because it permits a much faster evaluation of the adequacy of the sample and because it may avoid histologic methods in 76% of cases; 3. the smear cytology + microhistology combination seems to be the best solution (retrieval rate = 97.5%), but the costs are much higher because the cutting needle is somewhat expensive. The best solution would be to use the combination smear + inclusion cytology (retrieval rate = 89%) and to reserve the cutting needle for when aspiration needle material proves to be inadequate.