Abstract
A 47‐year‐old male patient presented with weight loss, hematuria, and a left renal mass, which proved to be a clear cell renal carcinoma with multiple liver, pulmonary and bone metastases. The platelet count was raised initially (414 × 10^9^/L) but declined 10 weeks after a debulking procedure followed by chemotherapy. Fibrin clots were prepared for scanning electron microscopy (SEM) by adding human thrombin to platelet rich plasma (derived by differential centrifugation of fresh blood samples taken from the patient as well as controls). The clots were washed, fixed in 2.5% glutaraldehyde and Dulbecos phosphate buffered saline and prepared for SEM with a Zeiss Ultra 55 FEG SEM. The SEM photographs revealed an altered morphology of the platelet aggregates with multiple breakages in the platelet membrane, showing a pock‐marked, crenated, prune‐like appearance as opposed to the smooth rounded globular membrane of the controls. The ultrastructural morphology of the fibrin bound platelet aggregates in this patient with renal carcinoma therefore showed a disrupted cytoskeletal architecture which appears to be similar to the apoptotic changes of programmed cell death as described by Bornman et al. (2007) and Pretorius et al. (2008). These features may well be a distinct ultrastructural hematological manifestation of a previously unidentified paraneoplastic syndrome. Microsc. Res. Tech. 2009. © 2009 Wiley‐Liss, Inc.