Atsumi Suzuki

Ameloblastic fibrosarcoma in the maxilla, malignant transformation of ameloblastic fibroma

This report presents a fatal case of ameloblastic fibrosarcoma arising from an ameloblastic fibroma, originating in the maxilla of 19-year-old Japanese male. An analysis of previously reported fatal cases of ameloblastic fibrosarcoma is included. In the course of the disease, the mesenchymal component of ameloblastic fibroma showed a dramatic histopathological transformation into sarcoma following multiple recurrence and the patient died of uncontrollable local infiltration of the cranial base. Although many cases have seemed to show disappearance of the epithelial component as malignant transformation progressed, many benign appearing ameloblastoid epithelial masses were scattered throughout the sarcomatous area even in the fatal stage in the present case. No distant metastases were found at autopsy. During multiple recurrences of the lesion, a little dysplastic dentin which was closely associated with both epithelial and mesenchymal components was found, though it could not be observed in autopsy material. Ultrastructural findings in autopsy material showed that the mesenchymal component consisted of undifferentiated mesenchymal cells, fibroblastic and fibrocytic cells with marked cellular and nuclear pleomorphism and that the epithelial component closely resembled the enamel organ.

Peripheral calcifying epithelial odontogenic tumor

Most of the calcifying epithelial odontogenic tumors (CEOT) are central lesions of the jaws, but the CEOT occurs infrequently on the gingiva. A cases of peripheral CEOT arising in the right upper molar gingiva of a 31-year-old Japanese woman is presented. A direct communication between the overlying gingival epithelium and the tumor was found by examination of serial sections. As a result, it was thought that one of the sources of peripheral CEOT might be gingival epithelium with potential proliferative activity.

Massive osteolysis of the mandible.

This report deals with a massive osteolysis, which is a rare disease characterized by the progressive dissolution of contiguous osseous structure, occurring in the mandible of a 46‐year‐old Japanese female. Histopathologic examination of the amputation material revealed that the mandibular body, ramus, condylar and coronoid processes were completely replaced by fibrous tissue, but inferior alveolar nerve and artery in the lesion were intact. A few small islands of osteoid tissue or immature fibrous bone were seen in the lesion. In the transitional area between the lesion and normal bone, active absorption of bone trabeculae was in progress and intertrabecular spaces were occupied by densely packed fibroblastic cells, however, angiomatous proliferation of vessels was not observed. A few bone trabeculae were surrounded by osteoclasts, but osteoclasts might not play a primary etiological role in massive osteolysis.

Harderianization is another sexual dimorphism of rat exorbital lacrimal gland.

The exorbital lacrimal glands (ELG) of rats were examined for both sexes to determine what degree of harderianization occurred as a function of age and after castration, and to investigate its time course and origin in ELG. Light microscopically, very small Harderian foci were seen in the ELG of both sexes at 3 weeks of age. As the male rats became older, the relative volume of the Harderian gland (HG) cells in the ELG increased. At age 6 months, the value was 1.25 +/- 0.31% in males and 0.13 +/- 0.05% in females (p less than 0.05). After castration, a significant decrease (0.21 +/- 0.01%, p less than 0.05) was observed in that of male ELG. In contrast, in female ELG, HG cells were inconspicuous and the relative volume of those did not vary during this experimental period or after castration. It appeared that the HG cells had developed from undifferentiated basal cells of the acini and the intercalated ducts in the ELG at age 2-6 months. Then, at age 22 months, they also probably developed from those of the excretory ducts of the ELG.

MELANOCYTES IN ODONTOGENIC KERATOCYST

Melanocytes in odontogenic keratocyst (OKC) were studied histopath‐ologically. As a result, melanocytes were observed within the basal layer of lining epithelium in five of 47 cases with OKC, with the overall prevalence being 10.6 per cent. Although no conclusion could be drawn from the present examination as to the origin of melanocytes in OKC, its possible histogenesis was discussed. ACTA PATHOL. JPN. 35: 899–903, 1985.

PIGMENTED VARIANT OF CALCIFYING ODONTOGENIC

A case of the pigmented variant of calcifying odontogenic cyst occurring in a 21‐year‐old Japanese male is reported, and a review of previously reported cases of the lesion is included. In addition to the characteristic histopathologic features of calcifying odontogenic cyst, dendritic cells containing melanin pigment were widely distributed in the epithelial layer and melanin pigment was also found in the epithelial cells including ghost cells in the present case. Although no conclusion could be drawn from the present examination as to the origin of melanin pigment in the calcifying odontogenic cyst, it is thought that the role of racial pigmentation is one of the important factors in occurrence of pigmented odontogenic lesions. ACTA PATHOL. JPN. 35 : 1023–1027, 1985.

Giant cell fibroma of the oral mucosa. Report of a case with ultrastructural study.

A case of giant cell fibroma of the oral mucosa found in a 3‐year‐old female is reported. The lesion was characterized histologically by the presence of numerous large stellate cells and multinucleated giant cells scattered in a loosely arranged collagen‐background. The large stellate cells had a large hyperchromatic nucleus, while the cytoplasm was well demarcated and frequently the cells had dendritic‐like processes. The multinucleated giant cells had similar morphology and occasionally resembled Langhans giant cells. Ultrastructural examination suggested that the multinucleated giant cells in the lesion were unusual fibroblasts. This is the first reported case of oral giant cell fibroma in a Japanese patient. ACTA PATHOL. JPN. 36: 1571‐1576,1986.

A sexual dimorphism of mucous cells in the submandibular salivary gland of rat

Submandibular glands of both sexes from one week to six months-old were serially sectioned, and mucous cells showing a strong positive stain to alcian blue pH 2.5, first detected at two weeks, showed a high degree of inter-sectional and inter-individual variability. In males, the percentage of animals having mucous cells increased with sexual maturation and attained 100 per cent at age six months. In females, the maximum (60 per cent) was reached by four weeks and then decreased with sexual maturation. Only 28.5 per cent of the glands of adult female rats contained mucous cells. In the six-month-old females, the percentage of female rats having mucous cells increased three-fold after injection of testosterone (total dose 17-21 mg; p less than 0.05, Fisher test). Mucous cells in testosterone-injected females displayed morphological features which suggest a transition from original seromucous cells to mucous cells.

Alveolar Bone Loss of Senescence-accelerated Mouse (SAM)

SAM-R/1/Iw (senescence-accelerated mouse, resistant) and Pl2/Iw (senescence-accelerated mouse, prone) under a conventional environment and eating standard pellets were examined for alveolar bone loss and the presence of periodontitis around maxillary and mandibular molars as a function of age. Neither SAM strain manifested a chronic periodontitis similar to that in humans, and no obvious plaque and calculus were observed. However, in both strains, 15% of M3 was lost after 13 months of age, and alveolar bone loss gradually increased with advancing age. Though there was no significant difference in the incidence of M3 loss between the two strains, P/2/Iw showed a higher alveolar bone loss around all molars than did Rl1/ Iw after one month of age throughout their life span. For Ml, the difference in alveolar bone loss between Pl2/Iw and Rl1/Iw was significant, and it was probably caused by the difference in degree of molar eruption. Other factors, such as occlusal trauma and gingivitis, may play some role in alveolar bone loss.

Glucocorticoid-induced growth inhibition with enhanced expression of ductal epithelium of human salivary gland adenocarcinoma cells transplanted into athymic nude mice.

The effect of glucocorticoid on growth and the histologic features of adenocarcinoma induced in nude mouse by the inoculation of neoplastic epithelial cells of salivary duct origin (HSG) were studied. Subcutaneous injection of dexamethasone (low‐dose group: 0.05 μg/g, high‐dose group: 0.25 μg/g) four times a week for 8 weeks significantly (P < 0.05) inhibited tumor growth, and in one mouse the tumor had almost completely disappeared by the middle of the sixth week of treatment. In addition, dexamethasone induced an apparent luminal structure in the tissue section of the tumor and enhanced the immunoperoxidase reaction to epithelial membrane antigen. The results indicate that dexamethasone inhibited the proliferation of HSG cells in the nude mouse transplantation system probably by inducing the cellular differentiation of the HSG cells toward the more differentiated ductal epithelia via glucocorticoid receptors.