The relationship between increased platelet count and megakaryocyte size in bronchial carcinoma.

This study investigates megakaryocyte size in bronchial carcinoma and its relationship to platelet count, mean platelet volume and platelet function, the latter determined in vivo by measurement of the cutaneous bleeding time. Measurements were performed in 19 patients with bronchial carcinoma and 11 patients with a hiatus hernia (controls). Platelet count (335 +/- 123 v. 241 +/- 72 x 10(9)/l) and megakaryocyte total area (772 +/- 135 v. 666 +/- 105 microns 2) (mean +/- standard deviation) were both significantly increased in patients with bronchial carcinoma when compared to controls whilst the bleeding time was shorter in the patient group (253 +/- 116 v. 321 +/- 80 s). Patients with bronchial carcinoma were older (60.2 +/- 8.4 v. 48.8 +/- 13.2 years) and smoked more heavily (760 +/- 511 v. 92 +/- 175 cigarette years) than controls. Megakaryocyte size, platelet count and bleeding time all correlated with smoking habit (r = 0.395, P = 0.031; r = 0.622, P less than 0.001; r = 0.515, P = 0.004 respectively). There were no statistically significant differences between the groups with respect to gender or mean platelet volume. When considering all patients, significant correlations existed between platelet count and megakaryocyte area (r = 0.400, P = 0.029), and bleeding time and megakaryocyte area (r = -0.365, P = 0.047). The megakaryocyte nuclear and cytoplasmic areas were positively correlated (r = 0.855, P less than 0.001). This study suggests that the elevated platelet count in patients with bronchial carcinoma is mediated by an increase in the size of bone marrow megakaryocytes although the results are compounded by the association between smoking and megakaryocyte/platelet parameters.