The modified processing of fine-needle aspiration cytologies from parotid tumors as a cell block: A reasonable extension of the diagnostic spectrum?

As part of the pre-therapeutic fine needle aspiration cytology (FNAC) of smear preparations, a dignity determination of parotid tumors is possible in teamwork with an experienced pathologist. The exact entity classification is not always possible due to the lack of additional tissue processing performing immunohistological, cytogenetic and molecular biological analyses. The aim of the work was to evaluate the diagnostic value of a modified technique using a cell block.

The FNAC sample was fixed in formalin. After centrifugation the cell block was paraffin-fixed in order to create section preparations followed by a hematoxylin-eosin staining. Depending on the first cytological findings further immunohistochemical stainings were performed.

FNAC was performed in 20 patients with parotid masses. In 19 cases diagnostic samples were sufficient. In 5 cases, diagnosis was confirmed by immunohistochemical characterization (2 lymphomas, 2 undifferentiated carcinomas, 1 squamous cell carcinoma). In addition, a supplementary cytogenetic analysis (FISH) was carried out technically correctly. In 17 out of 19 cases, the correct final diagnosis was possible using FNAC.

The work-up of FNAC as a cell block provides an extension of the diagnostic spectrum including the possibility of cytogenetic or molecular-biological additional investigations especially in the diagnostics of malignant parotid tumors. Given the options of personalized medicine and immunotherapies, this modified technique should be standard in future for minimally invasive assessment of tumor entity, PD-L1 receptor status, and genetic alterations.

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Publication History

Article published online:
10 June 2020