Histiocytosis X of the temporal bone: CT findings.

The preoperative diagnosis of temporal bone histiocytosis X has been based traditionally on clinical examination, plain radiography, and pluridirectional tomography. Clinical misdiagnosis is common because otologic findings can mimic those of acute and chronic infectious ear disease. Similarly, plain radiographic and tomographic findings may be confused with those of mastoiditis, cholesteatoma, and temporal bone metastasis. The three cases of histiocytosis X presented here illustrate the advantages of CT compared with traditional radiographic methods in the diagnosis and staging of this disease. Computed tomography clearly delineates osseous involvement, including erosion of the bony labyrinth. Computed tomography also better defines the soft tissue margins of the granulomatous mass in relationship to the central nervous system and extratemporal tissues.