Leydig Cell Tumor : Reinke's Crystalloids
Leydig cell tumor is composed of uniform round or polygonal cells with abundant eosinophilic cytoplasm resembling mature Leydig cells. Reinke's crystalloids are seen in about 30-40% of cases and appear as dense needle-like or rhomboid structures in the cytoplasm. They are difficult to visualize in histologic sections but are more readily seen in touch-preps made from the freshly cut tumor surface. This touch-prep was air-dried and stained with Diff-Quik stain. Several plump rod-shaped or rhomboid intracytoplasmic crystals of Reinke can be seen in the center of the image.