Cytomorphologic features of metastatic urothelial carcinoma in serous effusions

Our plain-English summary of Cytomorphologic features of metastatic urothelial carcinoma in serous effusions, by C.C. Huang, A. Attele, C.W. Michael (Diagnostic Cytopathology, 2013).

The study

• Authors: C.C. Huang, A. Attele, C.W. Michael
• Journal: Diagnostic Cytopathology
• Published: 2013;41(7):569-74
• Cited by: 11 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Metastatic urothelial carcinoma (UC) to serous effusion (SE) is extremely rare and its cytomorphological features have only been described in case reports. In this study, we searched the pathology database at University of Michigan for SEs due to metastatic UC in the last 20 years. A total of 25 cases from 20 patients with clinically and pathologically confirmed metastatic UC in SEs were retrieved. The specimens consisted of 15 pleural, 8 peritoneal, and 2 pericardial effusions. Smears were reviewed and evaluated for the following features: cellularity, single cells, cell clusters or short cords, cell wrapping, "windows" between the cells, two-tone cytoplasm, cytoplasmic vacuoles, signet ring cells, nuclear to cytoplasmic (N/C) ratio, nuclear hyperchromasia, irregular nuclear membrane, nuclear centricity, double or multiple nuclei, nucleoli, anaplastic cells and mitosis. Our results showed that UC manifested in SEs predominantly as a single cell population with or without clusters or short cords, and frequently exhibited the "cell wrapping" of two or more cells. Individual UC cell in SEs exhibited nuclear enlargement with increased N/C ratio, irregular nuclear membranes, hyperchromatic coarse chromatin and frequently prominent nucleoli. Double or multinucleated cells, cells with vacuolated cytoplasm or signet ring appearance were also frequently present. Our results demonstrated that while certain features could suggest the diagnosis of UC, the cytomorphological features are not specific and often overlap with those of reactive mesothelium, mesothelioma, metastatic adenocarcinoma, or squamous cell carcinoma in SEs. Accurate diagnosis of UC rests on the combination of clinical history, cytomorphologic features and appropriate immunohistochemical panel.

Copyright © 2012 Wiley Periodicals, Inc.

In plain English

This University of Michigan study reviewed 25 fluid samples from 20 patients (15 men, 5 women, aged 29 to 84). In each patient, urothelial carcinoma, a cancer of the bladder and urinary tract lining, had spread into the fluid around the lungs (15 samples), abdomen (8) or heart (2) between 1990 and 2011. The study did not look at asbestos exposure. Mesothelioma appears only as a condition these cancer cells can resemble. The cancer began in the bladder in 90% of cases and in the renal pelvis in 10%. Under the microscope, all 25 samples showed mostly scattered single cells. Clusters appeared in 10 samples (40%), short rows of cells in 8 (32%), and cells wrapped around other cells in 12 (48%). In immunostains of cell blocks made from the fluid, cells were positive for CK7 in 11 of 12 patients tested and CK20 in 10 of 12. The authors concluded that these features often overlap with those of reactive mesothelial cells, malignant mesothelioma, adenocarcinoma and squamous cell carcinoma. They said diagnosis rests on clinical history, cell appearance and immunostains.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: retrospective case series: review of fluid specimens retrieved from a pathology database
• Who was studied: 25 serous effusion specimens (15 pleural, 8 peritoneal, 2 pericardial) from 20 patients (15 males and 5 females, aged 29 to 84, mean 63.5) with metastatic urothelial carcinoma, University of Michigan, 1990 through 2011
• Exposure: No asbestos or other exposure was studied. The article concerns the microscopic appearance of metastatic urothelial carcinoma (from the urinary bladder or renal pelvis) in body-cavity fluids.
• Main results:
  • The primary cancer was in the urinary bladder in 90% of cases and in the renal pelvis in the remaining 10%
  • 11 patients (55%) developed the effusion within 1 year of the initial cancer diagnosis; the interval ranged from 1 to 228 months
  • All 25 specimens showed a predominantly single-cell pattern; mixed single cells and clusters were seen in 10 cases (40%)
  • Short cords of three to six cells were seen in 8 of the 25 cases (32%)
  • 'Cell wrapping' was seen in 12 of the 25 cases (48%)
  • 'Windows' between cells were seen in only 2 cases (8%)
  • Cells with two nuclei were seen in 60% of specimens and cells with multiple nuclei in 28%
  • Cytoplasmic vacuoles were seen in 48% of specimens and signet ring cells in 40%
  • Anaplastic tumor cells were seen in 12 cases (48%) and mitotic figures in 4 cases (16%)
  • Immunohistochemical stains were done on sections of cell blocks from 18 specimens (13 patients). Among the patients tested, the tumor cells were positive for CK7 in 11/12, for CK20 in 10/12 and for high molecular weight keratin in 4/4
  • The tumor cells were negative for WT-1, calretinin and CD68 in all cases stained
• The authors' conclusion: The authors concluded that metastatic urothelial carcinoma is rare in serous effusions and that its cell features often overlap with those of reactive mesothelium, malignant mesothelioma, metastatic adenocarcinoma and metastatic poorly differentiated squamous cell carcinoma. They said clinical history and immunostains are needed alongside the cell features to reach a diagnosis.

Topics

Medical terms in this study, explained in our Lexicon: Carcinoma, Pathology, Pericardial Effusion, Mesothelium, Mesothelioma, Adenocarcinoma, Squamous Cell Carcinoma.

Related studies

• Cytomorphological features of metastatic squamous cell carcinoma in serous effusions — C.C. Huang, C.W. Michael (2014)
• Cytological differential diagnosis among adenocarcinoma, epithelial mesothelioma, and reactive mesothelial cells in serous effusions by immunocytochemistry — X.Y. Su, G.D. Li, et al. (2011)
• MMP-7 is a highly specific negative marker for benign and malignant mesothelial cells in serous effusions — B. Davidson, H.T. Stavnes, et al. (2016)
• Utility of cytokeratin 20 in identifying the origin of metastatic carcinomas in effusions — V. Ascoli, S. Taccogna, et al. (1995)
• Morphologic and immunocytochemical performances of effusion cell blocks prepared using 3 different methods — X. Jing, Q.K. Li, et al. (2013)
• Detection of cancer cells in effusions from patients diagnosed with gynaecological malignancies. Evaluation of five epithelial markers — B. Davidson, B. Risberg, et al. (1999)

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