Internal Medicine

0521779407-17 CUNY1086/Karliner 0 521 77940 7 June 13, 2007 7:57

1184 Pleural Tumors

Thoracentesis:

■diagnosis often made by pleural fluid analysis – combination of cytol-

ogy and immunohistochemistry

Pleural Biopsy: low yield (≤15–20% positive)

Thoracoscopic or Open Biopsy: often required, especially for mesothe-

lioma

Specific Diagnostic Tests:

■Immunohistochemical markers

■Electron Microscopy

differential diagnosis

Malignant Mesothelioma

■effusion in 75%:

➣exudate; 50% serosanguinous

➣cytol positive in 25% (hard to distinguish from adenocarcinoma)

➣Immunohistochemistry: CEA, B72.3, Leu M1, Ber(EP4)

≥2 positive=adenocarcinoma

0 positive=mesothelioma

■pleural plaques in 30%

■EM of tissue can be diagnostic

Benign Fibrous Mesothelioma

■solitary, well-defined, often lobulated mass; 70% visceral, 30% pari-

etal

■10% with associated effusion

■highly vascular, often enhances with contrast on CT

Primary Effusion Lymphoma

■Distinctive cytologic morphology

Metastatic Pleural Disease

■exudative effusion; >50% are bloody

■cytology positive in 60–90%, especially adenocarcinoma

■thoracoscopy positive in 90%

management

What to Do First

■Thoracentesis, for diagnosis, and symptom relief

➣May reveal underlying pathology

General Measures

■Imaging: Chest X-ray, CT for staging