Purpose: To assess the diagnostic value of the orbital fine needle aspiration biopsy (FNAB) with an in vitro technique, eliminating the sampling error.
Design: Prospective, nonrandomized, interventional case series.
Methods: Sixty-eight patients were studied prospectively in institutional clinical practices. Immediately after excision of orbital mass lesions, the removed tissue was stabilized under the hand of the surgeon, and biopsied with a 23 or 25 gauge needle. The samples were processed for cytopathologic examination with Cytospin®; after this, the excised specimens were submitted for routine histologic examination. The cytopathologic diagnoses were compared with the final histopathologic diagnoses.
Results: Six out of 68 lesions were excluded and the remaining 62 cases were divided into 4 groups as primary malignant, primary benign, secondary malignant and inflammatory lesions, based on histopathologic diagnoses. In 43 cases the cytopathologic and histopathologic diagnoses were the same with a concordance rate of 69%. Among the malignant tumors, the cytopathologic diagnoses correlated with the histopathologic diagnoses in 14/14 and 17/27 cases of metastatic /secondary and primary orbital malignancies, respectively. Of 11 primary benign tumors, 2 cytopathologic diagnoses correlated with histopathology. In inflammatory lesions, the cytopathologic diagnoses were matched with the histopathologic diagnoses in 10/10 biopsies.
Conclusion: Even when the sampling error is eliminated with an “in vitro FNAB” technique the concordance rates between histopathologic and cytopathologic diagnoses varied considerably among different types of orbital mass lesions. FNAB diagnoses were most reliable in metastatic and secondary malignancies and inflammatory lesions and least reliable in benign orbital lesions.