The relationship between mandibular involvement by tumor (MI), the histological mode of tumor invasion (MTI), and the distribution of extracellular matrix in tumor (DECM) was clinically and immunohistologically investigated in a retrospective series of 37 patients with squamous cell carcinoma (SCC) of the lower alveolus and gingiva.
Mandibular involvement by tumor (MI) was evaluated based on the roentogenographic mode of mandibular resorption (RMMR) and the degree of mandibular resorption (DMR) . RMMR and DMR were classified according to the classification systems established by Swearingen (1966) and Totsuka (1985) . The mode of tumor invation (MTI) was assessed according to the classification system established by Yamamoto and Kohama (1983) . Furthermore, MIII was subclassified into two groups, MIIIa and MIIIb, according to the distribution of extracellular matrix.
Laminin, type-IV collagen, heparan-sulfate proteoglycan, fibronection, tenascin, vitronectin, and decorin in extracellular matrix were immunohistologically investigated.
The results obtained were as follows; 1) A clear relationship was found between the T-grade and the MI. 2) A positive relationship between MTI and MI was observed. 3) A relationship between RMMR and DECM was recognized.
These results suggested that detailed analysis of these factors could provide us with information useful in determining treatment plans for SCC of the lower gum.

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Fourteen patients, 80 years of age and older, with head and neck cancer who had visited our clinic from May 1974 to September 1992, were clinically assessed. Ten of those patients had visited our clinic within the last five years. One patient had multiple heterochronic oral cancers (lower gingiva and cheek mucosa) . Nine were male and five were female. Five carcinomas arose in the cheek mucosa, three in the upper gingiva, two each in the lower gingiva, maxillary sinus, and tongue, and one in the submandibular gland. Fourteen cancers (thirteen patients) were histologically squamous cell carcinoma and the other was adenocarcinoma. Two carcinomas were classified as stage I, four as stage II, two as stage III, and seven as stage IV. Seven patients (eight carcinomas) received primarily surgical treatment, six patients received primarily radiotherapy, and one patient received only chemotherapy because of alcoholism. It was possible to perform radical treatment in the early stages, but advanced cases were difficult to treat by radical therapy. However, the cases that had received semi-radical therapy tended to take a good course. Severe complications did not occur in our treatment, but hypoproteinemia and anemia arose frequently. The one-year, three-year, and five-year cumulative survival rates determined by Kaplan-Meier's method were 68.6%, 54.9%, and 36.6%, respectively.

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MRI (magnetic resonance imaging), along with CT (computed tomography), has become an essential imaging tool in the evaluation of head and neck tumors. Especially, since MRI has several advantages over CT, such as its superior soft tissue contrast and its less artifact from the base of the skull, air in the paranasal sinuses, and dental fillings, we feel that MRI is an excellent modality in the evaluation of oral and maxillo-facial lesions. However, it is felt that MRI has relatively low lesion specificity.
This investigation was undertaken to evaluate the clinical utility of MRI with Gd-DTPA (Gadolinium-diethylenetriamine pentaacetic acid) in the head and neck tumors. Ten patients with head and neck tumors were analyzed in this study. The results were as follows:
1) In cases of squamous cell carcinoma, tumors were weakly enhanced and showed low signal intensity compared with fat signal intensity.
2) In this study, there was a tumor that we could evaluate lesion conspicuity neither on non enhanced T1 and T2 weighted images nor on Gd-DTPA-enhanced T1 weighted images.
3) In the case of squamous cell carcinoma of the maxillary sinus, we could differentiate the tumor itself from secretions on Gd-DTPA-enhanced T1 weighted images.
4) In cases of squamous cell carcinoma of the tongue, which were easily affected by motion artifacts, we felt that Gd-DTPA-enhanced T1 weighted images were superior in terms of signal-to-noise ratio to T2 weighted images. We also felt that the Gd-DTPA-enhanced T1 weighted images were superior to T1 weighted images in terms of contrast between the tumor and the surrounding tissues.
5) In the recurrent case of adenoid cystic carcinoma, since the tumor were surrounded by fat degenerated tissues, the contrast between the tumor and the surrounding tissues was inferior to noncontrast T1 weighted images.

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The expression of the epidermal growth factor (EGF) and its relationship with cancer progression, histological malignancy, and the DNA ploidy pattecn was examined immunohistologically in 22 oral squamous cell carcinomas. The results obtained were as follows:
1. Tumor size (T) was not correlated with presence of EGF and DNA ploidy patterns.
2. Regional lymph node metastasis (N) was correlated with the presence of EGF and DNA ploidy patterns, suggesting that EGF immunoreactivity and nuclear DNA content may be a useful approach in obtaining information concerning its lymph node metastasis.
3. Histological malignancy was correlated with the presence of EGF and DNA ploidy pattecns.
4. The mode of invasion and the depth of invasion showed were correlated with the presence of EGF and DNA ploidy patterns, respectively, suggesting that EGF expression in oral squamous cell carcinoma is closely correlated with nuclear DNA content and the progression to advanced cancer.

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Squamous odontogenic tumor-like proliferation (SOTP) is a peculiar but benign lesion of the jaw-bone that was first described by W right in 1979. It is sometimes very difficult to differentiate such a lesion from true squamous odontogenic tumor (SOT) by histopathological examination alone.
This study is based on the histopathological and histochemical findings concering an SOTP lesion that was associated with a radicular cyst in the premolar region of the mandible of a 42-year-old Japanese woman. The results indicate that to clarify the biological nature of SOTP, further investigation concerning the pluripotentiality of the odontogenic epithelium is necessary.
This is the first case report of SOTP in Japan.

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Multiple carcinomas are observed more frequently today than in the past due to the development of methods of diagnosis and multidisciplinary treatment for carcinomas.
Here we report on a case of synchronous triple primary carcinomas, which occurred in the oral floor (squamous cell carcinoma), the kidney (renal cell carcinoma) and the liver (hepatocellular carcinoma) .
On April 18, 1991, a 75-year-old man, who had been hospitalized in the department of the urology for renal carcinoma and hepatocarcinoma, was referred to our department after complaining of painful ulcerated lesions on the left oral floor. An incisional biopsy was performed and a diagnosis of squamous cell carinoma of the floor (T2NOMO) was made.
Under general anesthesia, marginal mandibulectomy, tumor resection of the oral floor, right radical nephrectomy, and S₆ partial resection of the liver were performed. Postoperative radio-therapy and chemotherapy were also performed as an adjuvant therapy for oral carcinoma.
No evidence of recurrence or distant metastasis was apparent, and the patient appeared free of the disease for 2 years and 3 months after the operation.

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Two advanced cases of cemento-ossifying fibroma arising in the mandible were reported. The first case was found in a 46-year-old female with a cloudy radiopaque lesion at the 6-8 region. The other case was found in a 15-year-old female with a sharply demarcated radiolucent lesion at the 54 region. The histopathological lesions were diagnosed as cementifying fibroma and ossifying fibroma, respectively. Surgical enucleation followed by marginal osteotomy of the bone surrouding the lesion were performed. In these treatments, as much of the cortical bone of the mandible as possible was conserved to prevent postoperative complications such as pathological fracture. The results were satisfactory and to date no recurrence has been observed.

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