ReinkeKristalle

Reinke crystals, also known as Reinke crystalloids, are rod-shaped cytoplasmic inclusions found in Leydig cells of the testis. They were first described by the German anatomist Friedrich Reinke in the late 19th century and are named after him. Under light microscopy they appear as eosinophilic, crystalline-like inclusions within the cytoplasm of interstitial cells.

Morphology and composition: Reinke crystals are elongated cytoplasmic structures that can vary in appearance from simple rod-shaped bodies to more complex crystalline forms. The exact biochemical composition is not fully established, and there is no consensus on their functional role. Electron microscopy has shown a paracrystalline organization in some samples, but no definitive function has been proven.

Distribution and clinical relevance: Reinke crystals are normally found in Leydig cells of the testicular interstitium, where they may occur in healthy tissue as well as in association with Leydig cell tumors. Their presence is a historical histological feature that can support the identification of Leydig cell origin in a tumor sample, though they are not essential for diagnosis and can be absent in some tumors.

Function: The physiological role of Reinke crystals remains uncertain. They are generally considered inert cytoplasmic inclusions, and their appearance does not imply a specific metabolic function.

Historical note: The crystals are named after Friedrich Reinke, reflecting their initial description in the context of testicular histology and pathology. See also Leydig cell tumor and testicular interstitial tissue.