Among 1875 patients with palpable thyroid nodules examined with FNA cytology and LNAB histology, 132 with a preoperative FNA diagnosis of microfollicular nodule with atypical cells (n = 50) or suspected cancer (n = 82) were operated on. The 50 nodules showed the following preoperative LNAB finding: inadequate (8), benign (15), microfollicular (20), microfollicular with atypical cells (5), suspected cancer (2). The postoperative cancer incidence in the nodules with the benign LNAB diagnosis was 0% while it was 10%, 60% (P = 0.008), 100% (P = 0.007) in the other three LNAB diagnostic categories. The 82 nodules showed the following preoperative LNAB finding: inadequate (21), benign (21), microfollicular (15), microfollicular with atypical cells (15), suspected cancer (10). The postoperative incidence of cancer in the 21 (14%) and 10 (80%) nodules diagnosed by LNAB as benign nodule or suspected cancer, respectively, was significantly different (P = 0.0007). These data suggest that LNAB can be used for the preoperative selection of the palpable thyroid nodules diagnosed by FNA as a microfollicular nodule with atypical cells or suspected cancer.