Lymphocytic infiltration of pleural mesothelioma and its significance for survival.

Pleural mesothelioma is an uncommon but usually highly malignant tumour. A study has been made of 110 cases from the Mesothelioma Register of the National Centre for Occupational Health. Adequate information regarding survival was documented in 63 cases. In 5 of the latter there was insufficient tissue for accurate classification. Thirty-five patients were dead within 9 months of first presentation, and in 33 of these there was an insignificant or absent lymphoid reaction. Fifteen patients survived 18 months or more, and 10 of these had a significant lymphocytic infiltration in the original biopsies. In an intermediate group of 8 patients, who survived between 9 and 18 months, a variable lymphoid reaction occurred. We conclude that the presence of significant lymphoid infiltration indicates a better prognosis for longer survival in patients with pleural mesothelioma.