[461] Fine Needle Aspiration of Follicular Lymphoma: A Study of 109 Patients

SS Sikdar, HM Cramer. Indiana University School of Medicine, Indianapolis, IN

Background: The clinical value of fine needle aspiration (FNA) for the diagnosis of follicular lymphomas (FL) is often questioned since it is perceived that the FNA is usually followed by a confirmatory surgical biopsy. However, in our experience, therapeutic decisions for many patients with FL have been based solely on the FNA diagnosis.
Design: Our LIS was searched for the 19.5-year period ending July 8, 2009 and all cases in which FL was mentioned in the FNA or hematopathology (HP) reports were identified. All correlating FNA, HP and flow cytometry reports as well as all available clinical notes and selected microscopic slides were retrospectively reviewed.
Results: There were a total of 109 patients (111 cases) in this study, including 2 patients who each had 2 FNAs with 2 corresponding biopsies. Only 13 of our 109 patients (12%) had a concurrent HP biopsy at the time of the FNA. Of the 109 patients, 65 (60%) had an FNA diagnosis of FL that was not subject to HP confirmation and the FNA diagnosis was instrumental in determining the nature of further treatment. There were 27 FNA cases diagnosed as FL with HP follow-up and the FNA diagnosis was confirmed in 21 of 27 cases (78%). The 6 FNA discrepancies included: 1 case of Hashimoto's thyroiditis, 3 cases of diffuse large B-cell lymphoma (DLBCL), 1 case of B-cell lymphoma, not further classified and 1 case diagnosed as fibrous tissue with infiltrating lymphocytes. There were 19 cases of HP-proven follicular lymphoma that had not been diagnosed as FL by FNA. The FNA diagnoses for these 19 FL cases included: malignant lymphomas (ML) with various descriptors, that were incorrectly subclassified (9 patients, 47%), suspicious/highly suspicious for ML (4 patients, 21%), atypical lymphoid infiltrates consistent with ML (2 patients, 11%), lymphocyte population with abnormal flow cytometric findings (2 patients, 11%), rare atypical lymphoid cells (1 patient, 5%), and reactive lymph node (1 patient, 5%). The grade of FL as assessed on the FNA matched the HP grade in 12 cases of the 16 cases (75%) in which grade was mentioned in both the FNA and corresponding HP reports.
Conclusions: A diagnosis of FL was established by FNA in 92 of our 111 cases (83%) but the subtyping accuracy for those cases with HP follow-up was only 78% and grading accuracy was only 75%. Nonetheless, in 60% of our patients, treatment regimens appear to have been based only on the FNA diagnosis of FL. Given these results, the policy of basing treatment of patients with FL solely on the basis of an FNA diagnosis requires re-evaluation.
Category: Cytopathology

Wednesday, March 24, 2010 1:00 PM

Poster Session VI # 64, Wednesday Afternoon

 

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