Lipid crystals in malignant melanoma of the choroid.

The crystallization of extracellular lipid (other than cholesterol) in histologic preparation is a rarely observed phenomenon. The following case report describes lipid crystals within a necrotic uveal melanoma. Ultrastructural findings suggest that lipids released from necrotic lipidized melanoma cells were the source of the extracellular deposits. No unique lipids were identified from extracts of the tumor using thin layer chromatography. Energy dispersion microanalysis revealed elemental concentrations within the crystals comparable to intracellular organelles.