[Refinement of cytopathology of CT-guided fine needle aspiration biopsies with additional histologic examination of formalin-fixed blood-clots].

Purpose: To evaluate formalin-fixed blood-clot for diagnostic efficacy and safety in percutaneous CT-guided fine needle aspiration biopsy (FNAB) in addition to cytopathology.

Materials And Methods: 61 CT-guided FNABs were entered into a prospective trial. FNAB was performed in 22 female and 39 male patients (32 - 83 years, m = 62.8 +/- 10.9 y) using 20- (n = 7) and 22-gauge (n = 54) needles. After correct placement within the tumor, material for cytopathological work-up was harvested. Additional material was sampled by needling (stirring and aspirating) within the lesion. These blood-clots were fixed in buffered formalin and delivered for histopathological work-up along with the smears. All results were correlated with the clinical course of the patient; cases of negative biopsies underwent surgery or were followed clinically for a minimum of 13 months (m = 14.8 +/- 1.4 months). Finally, all puncture-related side-effects and complications were analyzed and compared with data from 108 transthoracic FNABs performed over a two-year period before using this technique.

Results: Tissue samples adequate for pathological diagnosis were obtained in 93.4 % (57 of 61 patients). Malignant cells were found in 50 samples, and 7 biopsy results were negative. The relevant pathological changes were depicted on both smear and blood-clot in 47 cases (82.4 %). In the remaining patients, the diagnoses were exclusively established by cytopathology (n = 6) and histopathology (n = 4). Altogether, additional information was obtained in 20 of the 57 FNABs (35.1 %). In the 47 cases with relevant findings obtained with both methods, the routine stain already led to the correct diagnosis in 9 cases by showing cohesive layers of malignant cells, and immunocytochemistry allowed subclassification of the biopsy material in additional 7 cases. Pneumothorax occurred in 12 of 38 transpleural punctures (31.6 %), hemoptysis in one patient (2.6 %). Four pneumothoraces required further treatment (3 thoracocenteses, 1 chest tube placement). Hemorrhagic complications requiring further treatment were not seen, but two minor hematomas were observed in the 19 abdominal punctures. The overall rate for pneumothorax was 38.9 % (42 of 108 interventions) for the FNAB performed in standard technique.

Conclusion: Histological work-up of sampled blood-clots yielded a higher accuracy of CT-guided FNABs. Additional immunocytochemical studies allowed subclassification of tumor material. The complication rate of this technique was not higher than for FNAB alone.