Cytologic Features of Metastatic Papillary Thyroid Carcinoma in Cervical Lymph Nodes on ThinPrep Based FNA Preparations.
Shaolei Lu, Bassam Aswad, Latha Pisharodi, Gengsheng Yu. Rhode Island Hospital, Providence
Background: Liquid based cytology preparations (ThinPrep) in fine needle aspiration (FNA) have certain advantages when compared to conventional smears. The lesional cells are well represented on the ThinPrep slide for pathologic evaluation. But the cytologic appearance of FNA specimen on Thinprep slide is different from the conventional smear due to the differences of processing methods. FNA of neck lymph node to confirm metastatic papillary thyroid carcinoma (PTC) is one of the most common procedures in fine needle aspirations. The knowledge of the cytologic features of metastatic PTC on a Thinprep slide is very useful in routine practice. In this study, we reviewed 70 cases of metastatic PTC in cervical lymph node prepared by the Thinprep methodology. Cytologic features were systematically analyzed and compared to those from conventional smears and the FNA of the primary thyroid lesion.
Design: Thinprep FNA slides from 70 cases of metastatic PTC in cervical lymph nodes between 2003 and 2010 were selected. All the aspirations were satisfactory for diagnosis and have previously or concurrently sampled surgical specimens. The observations were focused on the cellularity, nuclear enlargement, nuclear grooves, intranuclear vacuoles, hypochromasia, colloid, and nuclear overlapping. All the cases are reviewed by three cytopathologists and each cytologic feature was graded as present or absent.
Results: As compared to the conventional smear, the Thinprep method provided a cleaner background, less blood contamination but fewer fragments of thick colloid plaques. Fifty cases had multifocal tumors in primary lesion. Most FNAs had moderate to high cellularity with fewer cases showing intranuclear vacuoles. The papillary structures were well preserved in the ThinPrep slides and nearly all cases showed nuclear overlapping and enlargment. The tumor follicular cells appear proportionally smaller than those on conventional smears.
Conclusions: Most cases (50/70) of metastatic PTC had a primary thyroid carcinoma with at least 2 tumor foci. This might be an indication to have lymph node metastasis of PTC. ThinPrep preparations contained satisfactory amount of representative lesional cells for pathologic evaluation which is comparable to conventional smears. The cytology appearances of PTC on ThinPrep are different from those obtained from conventional smear and it is important to acknowledge the differences in routine practice when using Thinprep to prepare the FNA specimen.
Wednesday, March 2, 2011 1:00 PM
Poster Session VI # 56, Wednesday Afternoon