ANAPLASTIC THYROID-CARCINOMA IN FINE-NEEDLE ASPIRATES

OBJECTIVE: To analyze the diagnostic problems with fine needle aspirat ion biopsy in anaplastic thyroid carcinoma (ATC) and to describe the c ytomorphologic characteristics in 113 cases. STUDY DESIGN: A retrospec tive analysis of 113 fine needle aspirates and 67 surgical specimens f rom 113 patients with ATC admitted to the Institute of Oncology, Ljubl jana, in 1972-1992. RESULTS: In a series of 113 fine needle aspirates of ATC, 3 (2.7%) were inadequate, 3 (2.7%) suboptimal and 107 (94.7%) diagnostic of malignancy. On reexamination, 96/107 (89.7%) were diagno sed as ATC, 6 (5.6%) as differentiated thyroid carcinoma, and 5 (4.6%) as a malignant tumor not otherwise specified. As to the predominant c ell population, fine needle aspirates showed three different cell patt erns: (1) pleomorphic cell (43 cases), (2) round cell (33 cases), and (3) spindle cell pattern (7 cases). In the present retrospective analy sis we identified three main reasons for inadequate or nonrepresentati ve fine needle aspiration biopsy sampling: (1) tumor regressive change s (necrosis, hemorrhage, leukocytic infiltration), (2) extensive tumor fibrosis, and (3) distinct differentiated and anaplastic patterns in the same tumor. CONCLUSION: The major diagnostic problem with fine nee dle aspiration biopsy (FNAB) of ATC is related to sample quality. Cyto morphologic features of ATC are highly specific and easy to recognize. Due to the simple technique and high diagnostic accuracy, FNAB is the method of choice in patients with ATC.