[Parosteal osseous lipoma of the temporal bone concurrent with involvement of the parotid salivary gland].

The paper describes a case of parosteal lipoma of the temporal bone, by simultaneously involving the parotid salivary gland. Computed tomography performed in a 48-year-old man showed that in the area of the posterior edge of the glenoid fossa of the right temporal bone there was a massive (1.5×1.7×0.9-cm) exostosis extending down from the skull base. The exostosis was surrounded by a 3.5×3.6×5.3 soft tissue mass that was located in the projection of the right parotid salivary gland with a capsule and minor calcifications. Morphological examination determined a sessile exostosis-like mass in the area of the periosteum of the temporal bone. Foci of desmal and enchondral ossification (types III and IV according to the classification of Miller et al.) could be seen in the adjacent fatty tissue. The tumor underwent necrotic and dystrophic changes (Milgram's Stage 3). Temporal bone involvement was accompanied by osseous sialolipoma of the right parotid salivary gland. In this case, the fatty component accounted for 60-80% of salivary gland volume. Terminal secretory segments, ducts, and bone trabeculae with calcification foci and hematopoietic elements were uniformly distributed among the fatty tissue. None similar case has been found in the literature.