Granular cell tumors (GCTs) are rare, soft tissue tumors, and their histogenesis is still controversial, although the neurogenic theory, especially Schwann cell derivation, is considered the most plausible at present.
We studied eight cases of GCT clinicopathologically and immunohistochemically. The results were as follows:
1. Granular cells of GCT had a variety of sizes and shapes, were filled with fine eosinophilic granules, and showed lysosome-like characteristics, also with a variety of sizes and shapes, on electron microscopic observation.
2. Immunohistochemically, the intracytoplasmic granules showed positive reactions for S-100 protein, NSE, Kp-1 and diastase-resistant PAS staining but a negative reaction for a 1-antichymotrypsin. Additional lipid staining, such as oil red O, Sudan black B, and Nile blue, was performed in two cases, but was all negative.
3. In three cases, an appearance of transition from striated muscle fibers to granular cells, and the accumulation of intracytoplasmic granules with the shape of striated muscle fibers remaining were seen at the margin of GCT masses. In addition, four cases out of eight showed weakly positive reactions for myoglobin.
Thus, several cases were suggested to have a myogenic origin, and neither 5-100 protein nor NSE provided conclusive evidence of neurogenic origin due to their poor specificity. It was, therefore difficult to limit their derivation to neurogenic origin, and further examinations are required.
The accumulation of intracytoplasmic granules in other tumors, such as neurofibroma, which was referred to as granular cell neurofibroma by Enzinger and Weiss (1983), and leiomyoma, were previously reported. The neoplastic proliferation of granular cells seems unlikely in view of their few cell organelles on electron microscopic observation.
In order to explain our results and those of previous studies, it is most reasonable to consider that GCT is not a neoplastic lesion, that the accumulation of intracytoplasmic granules in GCT is the result of degenerative or reprocessing changes (Whitten, 1968), and that such “granular cell changes” occur in various tissues (Shear, 1960 and Millar, 1977).
Furthermore, previously reported “malignant” GCTs, which showed histological malignancy and remote metastasis and were often diagnosed with much difficulty, may include pre-existing malignant tumors with “granular cell changes”.

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The mandible, scapula, ilium, rib, and fibula of 36 cadavers for anatomic study were morphometrically analyzed and compared to determine the best suited free bone graft for reconstruction of the mandible. The thickness of the bone at the mandibular first molar region was 12±2mm. In contrast, the thickness of the central portion of the scapula was 11±1 mm, the ilium 15±2mm, the fibula 11±2mm, and the rib 9±2mm. The thickness of the body of the mandible at the first molar region was 24±6 mm, while the distance from the lateral margin of the central part of the scapula to the disappearance of cancellous bone on the medial side was 20±3mm. For the ilium, marrow was present from the supracrestal margin to 30mm inferiorly, and this region was harvestable. The sagittal diameter of the fibula was 14±2mm, and that of the rib 17±2mm. The results indicated that the ilium was relatively well suited for reconstruction of the body of the mandible. The scapula and fibula could be used for reconstruction judging from the thickness of the bone, but their height was not always sufficient.
The outer diameter of the vascular pedicle of the bone graft was generally about 3-4mm. The longest length of the graft vessels was 72±27mm for the fibula, and the shortest length was 56±14mm for the scapula. Since there was thus no great difference in the length of the vascular pedicle, the material best suited for the reconstruction of the mandible should be determined based on the morphologic characteristics of the bone graft. In conclusion, the ilium was relatively well suited for reconstruction of the body of the mandible, whereas the scapula, fibula, and rib lacked sufficient height.

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Hydroxyapatite (HA), which is the major inorganic component of bones and teeth, has been suggested to be formed via precursors, such as octacalcium phosphate (OCP). Previous studies reported that synthetic OCP stimulated osteogenesis if implanted into the subperiosteal region of murine bone. The present study was designed to investigate how implantation of OCP influences osteoblastic and/or osteoblastic progenitor cell populations residing in bone marrow.
OCP or HA was implanted into the bone marrow in the tibia of 6 week-old male Wistar rats through a small hole made at the mid-shaft of the bone. Only the hole, without any implant, was made in the control group. The rats were killed 1, 2, 4, and 8 weeks after implantation of OCP or HA, and the tibia was removed. The specimens were decalcified in 10% EDTA and processed for haematoxylin-eosin staining, histochemical analysis of tartrateresistant acid phosphatase activity (TRAP), and transmission electron microscopy.
Bone formation was initiated on the OCP implant in one week, whereas bone formation was not observed until 2 weeks after implantation of HA. Both OCP and HA implants were surrounded by multinucleated giant cells (MNGC), some of which were positive for TRAP histochemically. Part of the organic matrices that accumulated on OCP were also stained with TRAP. Transmission electron microscopic observation demonstrated that MNGC on the OCP implant had structures such as a clear zone and a ruffled border, which are characteristic of osteoclasts, whereas MNGC on the HA implant had a clear-zone-like structure, but no ruffled border.
The present study suggested that OCP could be resorbed by osteoclast-like cells and could be replaced by new bone formed by stimulated osteogenesis coupled with bone resorption.

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This study was carried out to investigate changes in the mandibular condyle, femoral head and vertebral trabeculae in rats with experimental osteoporosis induced by triethylene thio-phosphoramide (TEPA).
Wistar rats were divided into 2 groups: the normal group was given distilled water, and the TEPA group was given 10mg/kg of TEPA by hypodermic injection. Histopathological observation and measurement of quantitative percentages of trabecular areas, determined by binary images of the mandibular condyle, femoral head and fourth lumbar vertebra, were made 3 days, 5 days, 7 days, 10 days, and 14 days after the injection.
Histopathological observation showed that the cartilage layers had thinned, the cells of cartilage had decreased and dwarfed, and the matrix of cartilage and bone had decreased, especially at 5 days and 7 days in the TEPA group.
By trabecula area percentages, a decrease in area was found in the TEPA group, and the largest decrease was at 5 days after the injection.
An analysis of variance was made of the trabecular area percentages between the normal group and the TEPA group at the mandibular condyle, femoral head and fourth lumbar vertebra. The contribution ratios of the factor of TEPA injection were calculated with the following results: mandibular condyle, 30.63%; femoral head, 64.14%; fourth lumbar vertebra, 10.30%.
Therefore, the greatest decrease in bone area percentages in experimental osteoporosis induced by TEPA in rats was at the femoral head, followed by the mandibular condyle; the decrease in the fourth lumbar vertebra was found to be very slight.

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Thirty-seven cases of oral lichen planus (OLP) were investigated clinically, histologically, and immunohistochemically to examine the early characteristics of malignant transformation. OLP was clinically classified into 4 types: reticular (12 cases), erosive/ulcerative (21 cases), leukoplakic (3 cases), and erythroplakic (1 case). In 3 cases of erosive/ulcerative OLP, squamous cell carcinoma (SCC) coexisted. Histologically, the degree of epithelial thickening, subepithelial cell infiltration, cellular atypism, and liquefaction of the basal cell layer were more prominent in erosive/ulcerative type, especially in cases with coexisting SCC, than in reticular type. The proliferating potential of epithelial cells was immunohistochemically investigated using monoclonal antibodies to proliferating cell nuclear antigen (PCNA) and epidermal growth factor receptor (EGFR). Generally, the staining intensities of PCNA and EGF-R in OLP were not so different from those in the healthy oral mucosa. However, an increase of PCNA-positive cells was observed in some cases of erosive/ulcerative OLP, including 3 cases with SCC. The binding of the epithelium to 3 lectins, concanavalin A (Con A), soy bean agglutinin (SBA) and wheat germ agglutinin (WGA) was examined. In healthy oral mucosal epithelia, the binding to each lectin was weak in the basal cell layer and strong in the prickle cell layer. In OLP, bindings to the 3 lectins, especially to WGA, were decreased most prominently in the upper prickle cell layer. The strongest decrease in lectin binding was observed in erosive/ulcerative type. Conversely, Con A binding to the horny cell layer was increased in OLP.
These results suggest that OLP, especially erosive/ulcerative type, has the potential to undergo malignant transformation. Therefore, extensive and prolonged follow up is necessary for this type of OLP.

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The hemostatic effect of 1-deamino-8-D-arginine vasopressin (DDAVP) on tooth extraction was investigated in 7 patients with mild and moderate hemophilia A and von Willebrand disease. Tooth extraction was performed uneventfully on 10 occasions under DDAVP treatment. Primary hemostasis was completely achieved, and postoperative bleeding was not noted in any case. Four activities (VIII: C, VIEW: Ag, VIII R: Ag, VIII R: RC) of F VIII/vWF increased several times 30-60 minutes after DDAVP injection and remained high for 1-3 hours and returned to the initial levels after 24 hours. The increase was high enough to control the hemostasis in most cases, although the cases of hemophilia A showing low VIII: C and von Willebrand Type II A showing low VIII R: RC had a poorer response. These results indicate that DDAVP is useful for the control of hemostasis after tooth extraction in patients with hemophilia A and von Willebrand disease.

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Cogenital deficiency of α 2-plasmin inhibitor (α 2-PI) is a very rare hereditary disease associated with poor hemostasis. We successfully performed hemostatic management for intraoral bleeding on 11 occasions in three sisters with this condition in the manner described below.
Hemostatic laboratory tests in these patients showed an accelerated whole blood clot lysis time (3-4 h) and a short euglobulin lysis time (1.5-2 h). A very low activity and concentration of a 2-PI were also characteristically noted.
The following policy is recommended for the management of hemostasis:
1) For surgery, hemostasis can be obtained by oral administration of 10mg/kg of tranexsamic acid (t-AMCHA) every 6 hours (40mg/kg/day) from 3 hours preoperatively to the 7 th postoperative day.
2) When urgent hemostasis is necessitated by continuous bleeding, intravenous injection of 50mg/kg of t-AMCHA followed by oral administration of 25mg/kg/day of t-AMCHA for several days is effective for the maintainance of a high level of serum α 2-PI activity and proper hemostasis.
3) Hemostasis can be achieved by oral administration of 25-35mg/kg/day of t-AMCHA for several days in the case of minor superficial bleeding and hematoma.
4) Proper local hemostatic management is necessary for intraoral bleeding, in addition to improving the abnormal fibrinolytic state by t-AMCHA.

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A prospective study was undertaken to evaluate dry socket (alveolar osteitis) in 1146 patients who surgically underwent extraction of impacted third molars. Dry socket occurred at a total rate of 5.4%; 27 cases occurred in males and 35 in females. There were no sexual differences. The prevalence of dry socket was highest: patients 40 years of age or over, followed by those from 30 to less than 40, 20 to less than 30, and under 20 years old.

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Recently, we encounted a case of lymphoepithelial cyst with calcification which developed on the floor of the oral cavity. Here, we report the clinical course of this patient. On February 17, 1995, a 24-year-old woman presented at our department because of a mass on the right side of the floor of the oral cavity. Examination revealed an elastic hard mass of 5×5×3 mm in size, which had well-defined margins and a smooth surface mucosa. The mass, which caused neither spontaneous pain nor tenderness, was regarded as a movable tumor because of the absence of adhesion to the surrounding tissues. We performed a tumorectomy under local anesthesia. The pathological diagnosis was a lymphoepithelial cyst with calcification. Five months have passed since the operation. There are no signs of recurrence, and the patient's postoperative course is satisfactory.

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Thyroglossal duct cyst (TDC) often occurs as monolocular type between the foramen caecum of the tongue and the thyroid gland. We treated a case of bilocular TDC with dysphagia arising in both upper and lower sites of the hyoid bone. The hyoid bone was found to be located at the boundary between the bilocular cystic on contrast radiography. Cystic patterns were also found at the upper anterior and lower posterior areas of the hyoid bone on CT. The patient was admitted to the emergency room of our hospital because of dysphagia shortly after the first visit, and TDC was extirpated by Sistrunk's method under general anesthesia. No recurrence has been noted as of 7 years after the operation.

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Two cases of mucous membrane pemphigoid are presented. In the both cases bullae were formed on the gingivae only, with no involvement of the skin or other mucosa. They were diagnosed as mucous membrane pemphigoid by histopathogical findings and direct immunofluorescence technique. Topical steroids were effective. Both cases healed without scar formation, and there has been no recurrence. These findings suggest the existence of a variant type of mucous membrane pemphigoid that is limited to the oral mucosa and has a good prognosis.

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We report two rare cases of pigmented nevus of the oral mucosal membrane.
Case 1. A 16-year-old boy with a black tuberous solid mass on the left hard palate, was referred to our hospital. As a malignant melanoma was suspected, an excisional biopsy with the surrounding soft tissue including the periosteum was performed under general anesthesia in preparation for radical operation. The frozen section was diagnosed as an intramucosal nevus.
Case 2. A 52-year-old woman with a dark brown, pedunculated mass on the lower surface of tongue, was referred to our hospital. As a tumor was suspected, an excisional biopsy was performed under local anesthesia. Histopathologically, a diagnosis of intramucosal nevus was made.

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Two cases of burns of the oral mucosa (one electrical and one chemical) are reported.
Case 1. A case of an electrical burn to the oral cavity in a 4-year-old boy is presented. While the child was playing with a family computer, he put the socket into his mouth. When he was first examined at our hospital, the lip, tongue, and buccal mucosa were damaged. Because of intense pain, no oral ingestion of food in any form was possible. He was treated by intravenous drip infusion of antibiotics and fluid therapy. The treatment was mainly carried out conservatively, with no surgery. At present, after 6 years, the left side of the tongue has only a slight scar, but there is no functional disturbance.
Case 2. We encoutered a case of chemical burns of the oral cavity caused by the accidental ingestion of sodium hydroxide into the mouth. A 54-year-old man visited our hospital with a complaint of erosion of the tongue. He was treated by intravenous drip infusion of antibiotics and tube feeding through the nasal cavity.
A regular diet was given the next day. The burn healed in four weeks.

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