No abstract

The effects of static tympanic air pressure gradients on hearing sensitivity was studied by introducing overpressures of 100 mm H2O to 400 mm H2O into the ear canals of 22 normal subjects. Sweep frequency threshold measures were obtained using a pressure-tight probe transducer driven by a Bekesy automatic audiometer. These gradients of tympanic pressure disequilibrium produced threshold losses through 4000 Hz, most prominently for the region of 500 to 1000 Hz, that increased systematically with the degree of overpressure. The data may be useful in estimating the degree of conductive loss associated with middle ears presenting retraction without effusion and normally compliant though negatively skewed tympanograms.

Papillary cystadenoma lymphomatosum, or Warthin's tumor, is a benign lesion of the salivary glands occurring most frequently in the parotid region. Since the initial report of this lesion in 1910, numerous reports have appeared in the literature concerning the occurrence of Warthin's tumor in many extraparotid locations, including the larynx. The vast majority of those tumors arising in the larynx have been disproved because of the absence of one or more of the histologic characteristics of this lesion within the surgical specimen. This paper will review the histologic criteria of Warthin's tumor and the typical clinical occurrence. We will discuss a case of papillary cystadenoma lymphomatosum of the larynx that satisfies all the histologic criteria of this lesion. A review of the possible origins of this tumor will demonstrate that this case may lend support to the hypothesis that papillary cystadenoma lymphomatosum may be the end result of a delayed hypersensitivity reaction.

The ultrastructural features of a juvenile ossifying fibroma of the maxilla are described. The stromal portion of the tumor was composed of osteoblasts and to a lesser extent of fibroblasts. The bone spicules were rimmed by osteoblasts and osteoclasts. Calcification was seen to occur along the collagen fiber matrix, corresponding to calcification of osteoid, and also in the form of intracellular and extracellular crystallization. The latter form of calcification corresponded to so-called psammoma-like bodies, and was considered characteristic of this subtype of ossifying fibroma.Cancer 42:2668-2674, 1978.UVENILE OSSIFYING FIBROMA is a relatively rare fibro-osseous jaw lesion that occurs mostly in children. O t h e r names used for this lesion are young ossifying f i b r~m a ,~ psammoosteoid fibroma6 or juvenile active ossifying fibroma.8 The t u m o r is locally aggressive, a n d has a tendency t o recur. Morphologically it has the basic features of a n ossifying fibroma but also forms psammoma body-like islands in a highly cellular stroma, that contains numerous osteoblasts. Both morphologically a n d clinically, juvenile ossifying fibroma differs from other fibro-osseous lesions of t h e jaws, such as fibrous dysplasia, fibro-osteoma, giant cell tumor, cherubism, aneurysmal bone cysts, Paget's disease a n d various cemento-osteoid lesions. Various aspects of differential diagnosis ofjaw bone lesions were comprehensively reviewed by Hamner et a1.8 a n d Fu and P e r~i n .~ I n this report we present the ultrastructural features of a juvenile ossifying fibroma with special emphasis o n deposition of calcium crystals a n d formation of psammoma-like bodies. JFrom the

Sebaceous cell carcinoma is an extremely uncommon tumor; fewer than 100 cases have been reported, with most of these lesions arising in the meibomian glands in the tarsal plates. Other sites in the head and neck have been noted, but this is the first reported case originating in the external auditory canal.