Australian Society of CytologyCase of the Month
June 2004 - Answer and Discussion
Papillary mesothelioma.
Answer
The smears are highly cellular and have a bloody background.
There are many malignant papillary clusters and aggregates alongside numerous dissociated malignant cells. The cells have enlarged nuclei, moderately sized nucleoli and moderate to prominent amounts of cytoplasm.
No mucin production is identified.
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Features are those of a papillary neoplasm and in the differential diagnosis papillary carcinoma and papillary mesothelioma should be considered.
In the abdomen, metastasis from an ovarian tumour or a primary intra-abdominal tumour are possibilities.
Despite the patient’s previous history, metastasis from a breast carcinoma was considered unlikely as these tumours do not have a papillary appearance in the abdominal cavity.
Immunoprofile
CALRETININ |
CK5/6 |
CAM5.2 |
CEA |
+ |
+/- |
+ |
- |
CK7 |
CK20 |
B72.3 |
BerEP4 |
- |
- |
- |
- |
) |
) |
Strong positivity with Calretinin and CAM5.2, and some positive staining with CK5/6 indicates that the tumour is a mesothelioma rather than a carcinoma and is in keeping with a papillary mesothelioma.
These tumours occur mainly in the peritoneum and can be incidental findings a laparoscopic examinations.
They rarely cause effusions although some cases have been observed. With regard to this case, a previous left-sided pleural effusion showed atypical cells (not diagnostic of malignancy) which may be related.
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References:
- Gray W,McKee G,Diagnostic Cytopathology, 2nd Edition,Churchill Livingstone 2003.
- Geisinger K,Raab S,Stanley M,Silverman J,Abati A, Modern Cytopathology, Churchill Livingstone 2004.
