Cytodiagnosis of Coats' disease from an ocular aspirate. A case report

This paper describes the cytologic findings in a rare condition, Coats' disease, which was diagnosed from a sample of ocular aspirate in a 19-month-old boy. The cytologic findings were characterized by the presence of numerous cholesterol crystals, rare foamy macrophages, several pigment-laden macrophages, pigment-bearing epithelial cells and free pigment, which stained positive for melanin by Schmorl's stain. The case was unusual in that the clinical diagnosis was persistent hyperplastic primary vitreous, and other diagnoses, such as Coats' disease, were unsuspected. The cytologic findings suggested Coats' disease and seemed to exclude retinoblastoma or another malignancy, although the negative findings with the presence of cholesterol crystals and macrophages were regarded as somewhat nonspecific for unequivocally excluding any of the above.