Fine-needle aspiration to diagnose primary thyroid lymphomas: a systematic review and meta-analysis

Primary thyroid lymphoma (PTL) is a rare malignancy, and its prognosis depends significantly on its early diagnosis. While fine-needle aspiration (FNA) represents the gold standard to identify differentiated thyroid carcinoma, its reliability for the detection of PTL is still unclear. Here, we conducted a systematic review and meta-analysis to evaluate the diagnostic performance of FNA in PTL.

A comprehensive literature search of PubMed/MEDLINE and Scopus databases was conducted to retrieve papers reporting histologically proven PTL undergone FNA. The last search was performed in February 2018 without language and time restrictions.

Thirty-two studies describing 593 PTL were included and the pooled FNA sensitivity was 0.48 (95% CI = 0.38-0.58). FNA sensitivity was 0.51 in 20 studies published before 2010 and 0.39 in those published later, 0.50 in six articles with at least 20 cases and 0.44 in nine series enrolled after 2000. This performance was similar in 12 articles including diffuse large B-cell lymphoma (0.54) and those six on marginal zone lymphoma (0.56). Remarkably, FNA sensitivity increased to 0.72 when considering also FNA reports suspicious for PTL reported in 14 articles. Heterogeneity among the series was found. Publication bias was not always detected.

The present meta-analysis demonstrated that FNA has low sensitivity in diagnosing PTL. However, this rate increased when considering also FNA reports suspicious for PTL, which is relevant from a clinical standpoint. This result could support indirectly the use of additional imaging and/or core biopsy when PTL is suspected.