ENDOSCOPIC ULTRASOUND-GUIDED, 18-GAUGE, FINE-NEEDLE ASPIRATION BIOPSYOF THE PANCREAS USING A 2.8 MM CHANNEL CONVEX ARRAY ECHOENDOSCOPE

Background: Previous studies have reported on endoscopic ultrasound-gu ided, fine needle aspiration biopsy using 22- to 25-gauge needles. We evaluated the histologic and cytologic yield of endoscopic ultrasound- guided, fine needle aspiration biopsy of the pancreas using an 18-gaug e, Menghini-type core needle. Methods: Fine needle aspiration biopsy w as performed in conjunction with a prototype 2.8 mm channel convex arr ay echoendoscope. The core specimen was placed in formalin for cell bl ock, and residual material was expelled on slides for cytology. Defini tive diagnosis was established by surgery or clinical follow-up. Resul ts: Of 45 patients who underwent fine needle aspiration biopsy, the ne edle failed to penetrate indurated pancreatic lesions in five. An aver age of 2.6 passes were performed in the remaining patients. Sufficient material for a histologic and/or cytologic diagnosis was obtained in 40 patients (histologic and cytologic yield of 68% and 75%, respective ly). Combining the results of histology and cytology, the sensitivity and specificity for detection of malignancy was 76% and 100%, respecti vely. Histology confirmed the cytologic findings in 35 patients, provi ding additional tissue specific information. In three cases histology established a diagnosis of malignancy where cytology was not conclusiv ely malignant. However, in three cases of surgically confirmed maligna ncy histology failed to detect malignancy, whereas cytology showed sus picious or malignant cells. The sensitivity of histology and cytology alone in detecting malignancy was 53% and 70%, respectively. Mild panc reatitis occurred after pancreatic fine needle aspiration biopsy in on e patient. Conclusion: Core specimens for histology can be safely obta ined using an 18-gauge needle. Histology provides tissue-specific info rmation that complements cytology, but histology is less sensitive tha n cytology in detecting malignancy.