by Enrique Anton, MD, PhD

To the Editor:

Pistolesi et al (October 2004)¹ state that “diagnosis and management of malignant pleural mesothelioma (MPM) are major challenges that often frustrate both patient and clinician.” I would like to make the following comments.

Generally, malignant mesothelioma equates with a diffuse malignant mesothelioma, a rare and fatal tumor related frequently to asbestos exposure, which could arise from the surface of all serosas. The most frequent location is the pleura (> 90%), followed by the peritoneum (6 to 10%).² Although the majority of cases are unicavitary, sometimes simultaneous involvement of the pleura and peritoneum can occur.³

Unilateral pleural effusion, an early manifestation of MPM, is the most frequent radiographic finding in MPM,¹ and may be present in up to 95% of patients during clinical evolution.⁴ However, physicians should remember that the absence of pleural effusion is rare but possible,³ and pleural thickening and/or calcification could be the only finding.⁴

Pleural effusion is usually insufficient for diagnosing mesothelioma based on cytologic analysis alone.¹ However, when peritoneal involvement occurs and ascites are present, cytology could be a useful tool, helping in the diagnosis of mesothelioma.³

Currently, the outcome of MPM is unavoidably fatal; although the “median” survival is approximately 9 to 12 months,¹ occasionally an individual patient with mesothelioma could have a very poor outcome.³ Prognostic score systems have been developed in recent years¹ with the aim of being able to help in clinical trials. However, these systems applied to an individual patient could sometimes not be very reliable. If the five prognostic factors of the European Organization for Research and Treatment of Cancer⁵ were applied to the patient referred above,³ the patient would be classified in the good prognostic group (only two poor prognostic factors). In fact, he only lived 1 month after diagnosis.

In our daily clinical practice, physicians have to attend not to a “series” of patients with “mean” features but individual patients sometimes significantly different from classical descriptions. In addition to useful information provided in updates and reviews, we have to take into account other less-frequent features usually absent in these reports but with obvious usefulness for diagnosis and management of our real patients.