Magnetic resonance imaging (MRI) is superior to conventional X-ray tomography and CT scanning in detecting postoperative maxillary cysts (POMCs). We analyzed the MRI features of 51 cases (72 sides) and compared them with the operative findings of 42 cases (52 sides) of POMC. The total number of cysts diagnosed was 121. Multipe cysts were found in 37 sides (51%) and bilateral cysts were found in 21 cases (45%). According to classification of POMC based on location in the maxilla, the central cysts were found in only 38% of all cysts (peripheral ones in 62%). In the 42 patients operated on, 69 of 83 cysts which had been detected by MRI were confirmed, whereas there were two additional cysts which could not be diagnosed preoperatively. Sixty-four of 71 cysts were opened to the nasal cavity under endonasal endoscopic control. The other seven cysts (five sides) were operated on via a buccogingival incision. Detailed and accurate diagnosis by MRI and development of endoscopic instruments enabled endonasal surgery in most (91%) sides of the POMC. In five cysts of the superior type which are small, isolated and distant from the lateral wall of the nasal cavity, endoscopic endonasal surgery was not indicated. In conclusion, MRI for POMC was extremely helpful in selecting a surgical approach.

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Suppression of the 2f₁-f₂ distortion product (DP) by the third tone was measured in cochlear microphonics (CM) and otoacoustic emissions (OAEs) in guinea pigs to clarify the generation site of the DPs. The DPs were elicited by the primary tones with frequencies of 4.62 kHz (f₁) and 6 kHz (f₂). Five-dB-iso-suppression tuning curves (STCs) of the DPs were obtained by plotting the suppressor level as a function of its frequencies. The STCs in both CM-DP and DPOAE had the shape of the letter “V”with the tip centering around the frequency of f₂. The slopes of the STC on the higher frequency side were steeper than those on the lower side. As the intensity of the primary tones was decreased, the turning of the STC became sharper. These suppression properties indicate that the 2f₁-f₂ DPs were generated in the area on the basilar membrane where the characteristic frequency corresponded to those of primary tones, especially for the primaries at lower intensities. Because the suppression properties in CM-DP and DPOAE were similar to each other, we concluded that these two phenomena had a common generation site.

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Four cases of carotid body tumor are reported. Surgical removal of the tumor was performed in all cases. The internal carotid artery (ICA) was preserved in only two cases. In the other two cases ICA was unavoidably replaced by an EPTFE (expanded polytetrafluoroethylene) graft. In addition to the size and mobility in the anterior and posterior direction of the tumor, we concluded that CT and MRI were useful in decision of the surgical method. In case the ICA cannot be distinguished from the tumor at the bifurcation of the carotid artery on enhanced CT, it should be considered to be difficult to remove the tumor. MRI is suitable for discerning the inner surface of the carotid artery, but it is significant that MRI cannot necessarily reveal tumor invasion of the carotid artery wall.

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A clinical study was made of 1079 patients with previously untreated laryngeal cancer registered in our department during the 15 years between 1979 and 1993. Their mean age was 64.2 years, ranging from 22 to 91. The male to female ratio was 13: 1 and the proportion of non-smokers was 3.2%. These patients consisted of 687 with glottic carcinoma (64%), 373 with supraglottic carcinoma (35%) and 12 with subglottic carcinoma (1%). A sexual difference with regard to the proportion of glottic carcinoma was found; 66% in males and 39% in females. Therefore, the male to female ratios according to the primary sites were 22: 1 for the glottis and 8: 1 for the supraglottis.
According to the TNM classification (UICC 1987), there was a marked difference in the distribution between glottic type and supraglottic type: of the glottic type 439 cases (64%) were stage I, 159 (23%) stage II, 73 (11%) stage III, 16 (2%) stage IV, whereas of the supraglottic type 22 (6%) were stage I, 99 (27%) stage II, 136 (36%) stage III, 116 (31%) stage IV. Our treatment policy for laryngeal cancer has depended not only on the T stage but also on the cancer characteristics including the growing type, anatomical location and extension and depth of invasion. Of the 1079 patients, 1050 were treated radically, 17 palliatively and 12 were not treated. According to the T stage, radical irradiation was chosen for 410 cases (93%) of glottic T1, for 75 cases (45%) of glottic T2 and for 21 cases (81%) of supraglottic T1. Partial laryngectomy was performed in 16 patients (4%) with glottic T1, in 15 patients (10%) with glottic T2 and in 8 patients (6%) with supraglottic T2. Total laryngectomy was performed in almost all patients with T3, T4. The overall 5-year relative survival rate, cumulative crude survival rate and cause-specific survival rate were 84%, 72% and 88%, respectively. The survival rates for the glottic type were significantly higher than those for the supraglottic type (p<0.0001): the 5-year relative survival rate, cumulative crude survival rate and cause-specific survival rate for the glottic type were 93%, 80%, and 95%, whereas for the supraglottic type they were 68%, 58% and 76%, respectively. The 5-year relative survival rates for stage I through stage IV were 96%, 87%, 72% and 53% overall and they were 98%, 91%, 74% and 52% for the glottic type, whereas they were 67%, 83%, 70% and 52% for the supraglottic type, respectively. The results suggested that the better survival rate for glottic T1, which accounted for 64% of all glottic cases, made a great difference in the survival rate between glottic and supraglottic carcinoma.

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In recent years an increase in the incidence of esophageal injury due to battery ingestion by infants with miniaturization of batteries has been noted. A case of esophageal ulceration due to lithium battery ingestion is reported. Moreover, an experimental model of esophageal injury due to litium battery ingestion was produced in dogs, and the tissue damage was evaluted histologically. When the battery was inserted and left in the esophagus for one hour, the structure of the esophagus was well preserved. Minor injury was histologically found in the group in which the battery was retained for two hours. Esophageal injury from the epithelium to the muscle layer was found when the battery was retained for four hours. On the basis of our experimental findings, early extraction within four hours is desirable in the case of an esophageal foreign body of electric battery.

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The DNA ploidy patterns of fresh specimens from 145 patients with squamous cell carcinoma of the oral cavity and the pharynx were analyzed. The specimens were embedded in paraffin and the DNA ploidy patterns were analyzed mainly by flow cytometry. Aneuploid patterns were found in 70%, and they were found more frequently in hypopharyngeal carcinomas than in oral cavity carcinomas. Correlation between DNA ploidy and tumor size was statistically significant, but metastasis to lymph nodes and clinical stage were not correlated. In stage I and II oral cavity carcinomas and stage III and IV epi- and oropharyngeal carcinomas, survival was much poorer in the aneuploid than in the diploid group. Analysis of 30 patients showed better response to preoperative chemotherapy in the aneuploid than in the diploid group; the mean efficacy rates were as high as 68% in the aneuploid and 48% in the diploid group. Aneuploidy with a low DNA index did not respond well to chemotherapy compared with those with a high DNA index. DNA heterogeneity was found in 22% (4/18) of the oral cavity carcinomas and in 50% (6/12) of the hypopharyngeal carcinomas.

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