[Spindle cell lipoma--light and electron microscopic studies of two cases]

Two spindle cell lipomas, one in the subcutis of the posterior neck and the other in the deeper site of the right supraclavicular fossa below the brachial plexus, were studied by light and electron microscopy. Both were histologically composed of a mixture of mature lipocytes and uniform spindle cells within mucinous matrix associated with scattered birefringent collagen fibers. Ultrastructural observation revealed lipid droplets and discontinuous extracellular lamina in the small part of the spindle cells, indicating the earliest differentiation towards adipocyte.