Circulating Charcot-Leyden crystals in the hypereosinophilic syndrome

A patient who had malignant melanoma associated with the hypereosinophilic syndrome died of cardiovascular thrombotic lesions. Widespread tissue eosinophilia was accompanied by numerous Charcot-Leyden crystals in the tumor as well as in various organs, including the renal tubules. A unique observation, not previously described, is the finding of Charcot-Leyden crystals in the thrombi and vessels, including the renal glomeruli. While little is known of the significance of Charcot-Leyden crystals, it is speculated that the circulating crystals injure the endothelium and trigger intravascular coagulation, resulting in thrombosis. A search for the crystals in blood and/or urine may be of additional aid in the evaluation of the extent of the thrombotic process. A special staining method is proposed to facilitate recognition of the crystals, since these are virtually not visualized by routine stain. With the use of such a staining method, future observations in other cases of the hypereosinophilic syndrome may elucidate the role of Charcot-Leyden crystals in the pathogenesis of the thrombotic cardiovascular lesions of this syndrome.