Using fluorescent in situ hybridisation to diagnose mesothelioma in effusion cytology: the auckland experience so far with emphasis on difficult cases

Abstract

<h3>Aims</h3> To evaluate the clinical, radiological and cytological features of cases where fluorescent <i>in situ</i> hybridisation (FISH) was used in effusion cytology for suspected malignant mesothelioma. Cytology, immunohistochemistry and FISH will be correlated with histology. We will also briefly discuss problem cases. <h3>Methods</h3> The cytology database was searched for all effusion cytology cases where FISH was requested to distinguish reactive mesothelium from malignant mesothelioma. Clinical history, radiology, cytology, immunohistochemistry, FISH findings and histology were reviewed. <h3>Results</h3> The mesothelioma FISH panel was requested in nine cases since it became available at LabPlus in March 2010. Median age was 71 and most patients presented with recurrent pleural effusions and pleural thickening or masses on CT scan. One patient had an unusual clinical presentation and two patients had atypical radiological findings. Histological confirmation of malignant mesothelioma was available in seven cases. FISH indicated malignancy in six of these. The remaining case that was negative for malignancy on FISH showed suspicious cytology and immunohis-tochemistry compatible with malignant mesothelioma. <h3>Conclusions</h3> FISH is useful in the cytological diagnosis of malignant mesothelioma. However, results should be interpreted with caution and in conjunction with clinical, radiological and cytologi-cal findings.