Clear cell changes may be observed in any benign or malignant tumor of epithelial, mesenchymal, melanocytic and hematopoietic derivation . They are attributable to various factors including artifactual changes, improper cellular preservation and hydropic degeneration of organelles, or due to the accumulation of glycogen, mucopolysaccharides, lipid, mucin, or phagocytized foreign body material in the cytoplasm of tumor cells. This literature will selectively discuss the causes of clearing of cells and the pathological features of tumors with clear cell changes, which, at times, may pose a diagnostic challenge and dilemma. The biological behaviour may range from indolent to aggressiveness. But in most of the cases the presence of clear cells tumor may be a sign of increased tumor aggressiveness and malignancy. Thus their appropriate designation is critical.