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Volume 4 No. 1, January 2009 |
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Differential Diagnosis of Reactive Mesothelial Cells and Metastatic
Adenocarcinoma Cells in Pleural Effusion Using an
Immunohistochemical Panel
Department of Pathology, Faculty of Medicine, Tanta University,
Egypt
Background/Aim: the morphological evaluation of cytological
specimen from body cavity fluids presents difficulties in the
differential diagnosis between benign reactive mesothelial cells
(RM) and adenocarcinoma (AC). This is particularly challenging when
the malignant effusion is the patient’s initial presentation or when
the patient has a history of more than one primary. The use of
immunostains has several applications in the evaluation of pulmonary
and pleural neoplasms. The aim of our study was to investigate
whether a panel of immunohistochemical stains can offer a reliable
differential diagnosis of RM, metastatic AC of different types.
Patients &Methods: this study was performed on 31 cases of pleural
effusion. Ten cases were reactive mesothelial cells, and twenty one
cases were metastatic adenocarcinoma from lung, breast, ovary, and
lower GIT. A panel of immunohistochemical markers composed of
calretinin, CEA, and Ber-EP4 was used to differentiate between RM
and AC. Another panel composed of TTF1, WT1, CK7, CK20, and GCDFP15
was used to differentiate between the metastatic AC according to
their primary origin. Results: it was found that all cases of RM
were immunopositive for calretinin while 95.2% of the cases of AC
were positive for CEA, and 85.7% of AC cases were positive for
Ber-Ep4. The metastatic lung carcinoma cases were positive for TTF1
and CK7. The breast AC cases were positive for CK7 and GCDFP15.
Cases of metastasis from ovarian carcinoma were positive for CK7 and
WT1, while the cases of metastatic carcinoma from GIT were only
positive for CK20. Conclusion: immunohistochemical stains provide
the greatest aid in differentiation between RM and AC. Also they are
very useful in establishing the site of origin of metastatic AC. |
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