Myoepithelial and basal cells were identified by a monoclonal antibody raised against keratin. This antibody (CK B1) which detects myoepithelial cells in normal salivary glands, labels spindle shaped and polygonal cells in pleomorphic adenomas. Most cells in adenoid cystic carcinomas and some basal cells in adenolymphomas were also positive for this antibody. The oncocytic epithelium of adenolymphoma was negative. An inverse reaction was seen with an antibody against cytokeratin 18. The antibody CK B1 seems to be of interest for the detection of myoepithelial/basal cells in salivary glands and salivary gland tumours.

We studied human middle ears from Wittmaack's temporal bone collection in the ENT Department of the University of Hamburg. In the 12-week-old fetus, cells from the embryonic middle ear mesenchyme form a tiny semi-circle around the tympanic part of the developing facial nerve. During the following weeks, the production of fibrillar material increases until the facial nerve is surrounded by a dense fibrous semi-canal. Intramembranous ossification starts from ossification centers in the anlage of the membranous facial canal. Bone appears first in the form of spicules surrounded by osteoblasts. At this time, so-called aplastic areas (aplastische Zonen) can be identified between these spicules. Their importance in the latter occurrence of dehiscenses in the mature facial canal is discussed.

The normal pneumatization in human middle ears from Wittmaack’s temporal bone collection (ENT Clinic, University of Hamburg Medical School) is investigated by means of light microscopy and compared with electron-microscopic findings in the rat. The fetal middle ear in man and rats is completely filled with mesenchyme. The compartmentalization of the middle ear by the associated mucosal folds of the ossicular chain and the middle ear pneumatization are results of the resorption of the mesenchyme present. Ultrastructural findings in the rat’s middle ear reinforce light-microscopic studies and provide evidence of the fibrillogenesis which characterizes the transformation of the mesenchyme into the tunica propria of the middle ear mucosa. The microtopography of mesenchymal remnants in middle ears of neonates and in children during the first year of life and their relevance as to the pathogenesis of the primary acquired keratoma (cholesteatoma) are discussed.

The endochondral layer of the osseous labyrinth in the rat, golden hamster, mouse, guingea pig, pig, rabbit, cat, dog and monkey was studied and compared with that of man. (1) With the exception of the mouse and golden hamster, interglobular spaces were found. (2) In all species but the rat, the interglobular spaces contain acid mucopolysaccharides. An analogy between these structures and the ‘basophilic islands’ (basophile Inseln) is discussed. (3) Extension, arrangement, direction, occurrence and frequency of interglobular spaces vary within each species so that no constant relations could be found, which are also lacking in man. Possible reasons for the persistence throughout life of interglobular spaces in the osseous labyrinth of man and some mammals are discussed.

In regard to prognosis of external auditory meatus carcinoma, early diagnosis is of vital importance. Especially older patients (50-80 years) who previously have had no history of ear disease should undergo early computer tomographical examination and biopsy in cases of recurrent external otitis.