Send to

Choose Destination
See comment in PubMed Commons below
Cytopathology. 2014 Apr;25(2):112-9. doi: 10.1111/cyt.12065. Epub 2013 Apr 17.

Cytomorphological features of metastatic squamous cell carcinoma in serous effusions.

Author information

  • 1Department of Pathology, University of Michigan, Ann Arbor, MI, USA.



To study the cytomorphological features of squamous cell carcinoma (SCC) in serous effusions.


Conventional smears from 23 SCC were reviewed for the following features: cellularity, single cells, cell clusters, long cords, squamous pearls, cell-in-cell, 'windows', polygonal cells, anucleated cells, tadpole cells, fibre cells, third-type cells, refractile cytoplasmic ring, two-tone cytoplasm, cytoplasmic density, cytoplasmic vacuoles, signet ring cells, nuclear/cytoplasmic ratio, nuclear hyperchromasia, irregular nuclear membrane, nuclear centricity, double or multiple nuclei, nucleolus, anaplastic cells and mitosis. Subsequently, we also reviewed 15 reactive mesothelium, 18 mesotheliomas and 24 adenocarcinomas for comparison.


Most SCC smears comprised mixed populations of single cells and cell clusters. Keratinized squamous cells and squamous pearls were diagnostic for well-differentiated SCC. Squamous eddies, appreciated on the cell block sections appearing as two-dimensional cell clusters with a swirling pattern, were characteristic for SCC. Poorly differentiated/third-type cells with atypical cytoplasmic keratinization, manifest as two-tone cytoplasm with a well-defined border and occasionally a refractile central ring, were an important clue for the squamous origin of the cells. Features including cell-in-cell, cytoplasmic vacuolation, double or multinucleated cells, anaplastic cells and mitotic figures were present in various degrees, and were not of diagnostic value.


Certain cytological features are diagnostic for SCC, whereas other features of poorly differentiated SCC often overlap with those of reactive mesothelial cells, mesothelioma, metastatic adenocarcinoma or urothelial carcinoma in serous effusions. The combination of clinical history, appropriate immunohistochemical panel and cytomorphological features are important to ensure a correct diagnosis.

© 2013 John Wiley & Sons Ltd.


cytopathology; differential diagnosis; metastatic carcinoma; serous effusions; squamous cell carcinoma

[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Wiley
    Loading ...
    Write to the Help Desk