Thrombocytosis in malignant pleural mesothelioma.

The prevalence of thrombocytosis (defined as a platelet count above 400,000/mm3 in at least two examinations) and the prevalence of thromboembolism were retrospectively investigated in a series of 41 patients with malignant pleural mesothelioma and in 40 subjects with non small cell lung carcinoma. All the patients were examined at necropsy. The mesothelioma patients showed a higher prevalence of thrombocytosis (56.8% vs 24.2%; p less than 0.01). However, the prevalences of thromboembolism were similar in the two groups of patients (36.6% and 32.5% respectively). Among those with mesothelioma the prevalence of thrombocytosis varied widely from one histological type to another (76.9% in mixed type, 57.1% in the epithelial, and 30% in the sarcomatous type), the difference between mixed and sarcomatous being statistically significant (p less than 0.01). Moreover, the mesothelioma patients of under 70 years had thrombocytosis more often than those over 70 (80% vs 29.4%; p less than 0.01).