The diagnosis of malignant mesothelioma

Cytologic diagnosis of malignant mesothelioma, with particular emphasis on the epithelial noncohesive cell type

The effusion cytologies from 21 cases of malignant mesothelioma (MM) (15 pleural, 6 peritoneal) diagnosed at the Indiana University Medical Center during 1990-1997 were reviewed. Using the classification of Tao (Acta Cytol 1979;23:209-213), 13 cases of MM were of the epithelial cohesive cell type and 8 were of the epithelial noncohesive cell type. While the epithelial cohesive cell type has been discussed in the literature, the epithelial noncohesive cell type has not. The cytomorphologic features for both types are presented with particular emphasis on the noncohesive cell type. The differential diagnosis and use of ancillary confirmatory laboratory tests are briefly discussed. Because of its resemblance to florid reactive mesothelial hyperplasia and the general lack of awareness of the existence of the single-cell pattern of mesothelioma, this diagnosis can often be missed.

[Pleural mesothelioma--problems in diagnosis and clinical course in 25 patients]

Patients with benign pleurafibromas should undergo surgery as suspect thoracic tumors have the potential to become malignant. In benign cases diagnosis can easily be made during the operation. In such a case the prognosis is good and it is seldom necessary to undergo repeated surgery due to recurrence. In the case of malignant pleuramesothelioma the preoperative diagnosis with an exact staging of the tumor is very important to determine an adequate therapeutic regimen. X-ray, CT-scanning, tapping of the pleura fluid and biopsy of the pleura are together insufficient to diagnose a pleuramesothelioma correctly. Since it is not always possible to diagnose a malignant pleuramesothelioma even at thoracoscopy, one should not hesitate to perform an open lung biopsy in order to obtain enough material under adequate vision.