No abstract

More than one-third of the UUT cytological cases were classified as AUC and approximately 1/15 as suspicious or positive for HGUC. Based on UUT cytology specimens, the risk of malignancy of each cytological diagnostic category of TPS was comparable to those reported in the literature. The use of TPS in evaluating UUT cytology specimens was specific and sensitive in identifying patients with HGUC by histology.

nCLE of lymph nodes at the time of EUS is feasible and appears to be safe. Dark pleomorphic cells were readily identified in all of the malignant lymph nodes and correlated with tumor cells seen on histology.

Although papillary thyroid carcinoma (PTC) usually has classic cytological characteristics on fine-needle aspiration (FNA), it can present rarely with aberrant features resembling those of histiocytes in a cystic nodule. The aim of the current study was to describe PTC with atypical histiocytoid cells and distinguish it from benign histiocytes. A retrospective computerized search for FNAs with atypical features suggestive of PTC and cystic degeneration was performed, and if available, the corresponding resection specimens were compared. Four cases met the criteria for FNAs and three had surgical pathology follow-up, which showed PTC. One aspirate had some features typical of PTC, but the remaining FNAs had atypical histiocytoid cells, which had traits intermediate between those of PTC and histiocytes. Large cell size, pseudoinclusions, nuclear grooves, and multiple well-defined vacuoles in atypical histiocytoid cells favor PTC over benign histiocytes. Ancillary immunocytochemical studies can also be useful in confirming the diagnosis. Histiocytic cells are frequently present in thyroid aspirates, and occasionally, they have atypical features that represent an unusual presentation of PTC. Closer examination of these cells can provide diagnostic clues for preventing false-negative diagnosis of PTC.