Fine-needle aspiration biopsy of the retroperitoneum: a series of 111 cases not including specific organs.

We report on our experience in fine-needle aspiration (FNA) biopsy of the retroperitoneum: 111 FNA biopsies performed on 99 patients. Cytologic diagnoses were divided into four groups: nondiagnostic (unsatisfactory samples because of a low cellularity and/or improperly prepared smears) aspirates (20%), benign (16%), suspicious for malignancy (13%), and malignant (50%). There were no known false-positive samples. We had two false-negative diagnoses due to sampling errors. Among diagnostic smears, the procedure showed a sensitivity of 97% and a specificity of 100%. The predictive value of a positive result was 100% and the predictive value of a negative result was 90%. The overall accuracy was 98%. Metastatic carcinomas accounted for the largest number of lesions in the group of malignant tumors. A primary tumor site was known for the majority of the cases before the aspiration was performed. In the remaining cases we were unable to suggest an origin. It is therefore important to emphasize the role of ancillary studies in patients that are at the first assessment of the disease or when a second intercurrent malignancy is suspected. In our limited experience, a suggestion of the correct subtype of retroperitoneal sarcoma was not possible. As in the rest of cytopathology, a multidisciplinary approach is mandatory in this setting to improve patient management.