DIAGNOSTIC PITFALLS IN FINE-NEEDLE ASPIRATION BIOPSY OF THE MEDIASTINUM

A retrospective review of 189 fine-needle aspiration (FNA) biopsies of the mediastinum from four university medical centers was performed. R eview of Diff-Quik- and Palpanicolaou-stained dir ect smears was perfo rmed from a series of 189 FNA biopsies along with surgical pathology c orrelation obtained in 42% of the cases. There rr ere 28 (14.8%) nondi agnostic or unsatisfactory for diagnosis cases. Of the satisfactory FN A specimens with histologic correlation, 12 cases (6%) were discordant . These errors primarily involve subclassification of small-cell malig nancies involving the mediastinum, including a misdiagnosis of small-c ell carcinoma for lymphoma. Large-cell lesions that were problematic i ncluded the accurate diagnosis of Hodgkin's lymphoma including the sep aration from non-Hodgkin's lymphoma. Large-cell lymphoma with sclerosi s was misinterpreted in two cases due to distortion of cells by the me senchymal tissue and sparsely cellular smears. In two cases classifica tion of primary germ-cell tumors and separation from metastatic carcin oma was a problem. In general, FNA of the mediastinum is ail accurate procedure, but cart be challenging in a minority of cases dire to spar se cellularity of the lesions and accurate classification of a variety of neoplasms that occur in this region. These 12 discordant cases ser ve as the basis of our report. (C) 1997 Wiley-Liss, Inc.