Cyclooxygenases (COXs) are rate-limiting enzymes that initiate the conversion of arachidonic acid to prostanoids. COXs are classified into two isoforms: COX-1 and COX-2. COX-2 is an inducible isoform upregulated by proinflammatory cytokines. Recently, prominent COX-2 expression has been reported in several human cancers, including carcinoma of the colon, breast, lung, head and neck, and gallbladder. Overexpression of COX-2, which is involved in cell proliferation via prostaglandin E2 (PGE2) synthesis, may play a role in tumor progression. In this study, we immunohistochemically characterized COX-2 expression in various diseases of the maxillary sinus, including 5 cases of postoperative maxillary cyst, 5 of maxillary sinusitis, 5 of inverted papilloma, and 5 of maxillary sinus carcinoma. In addition, secretory phospholipase A2-V, CD3, CD20, and CD68 expression in these lesions was also examined to clarify the relation to COX-2 upregulation. COX-2 was not expressed in the ciliated columnar epithelium in sinusitis, but was expressed in squamous cell metaplasia in maxillary cyst and inverted papilloma. In carcinoma of the maxillary sinus, COX-2 was overexpressed in numerous cancer cells. The proportions of CD3 and CD68 positive cells in carcinoma were clearly lower than those in sinusitis. These results indicated that COX-2 expression correlates with squamous cell metaplasia and epithelial cell proliferation. The end product of the arachidonic acid cascade, PGE2, may be involved in downregulation of CD3 and CD68 and the proliferation of maxillary sinus carcinoma. Further studies of COX-2 inhibitors as potential antitumor agents in maxillary sinus carcinoma are warranted.
Recent studies using novel bioengineering techniques have demonstrated the regeneration of mammalian dental tissues from tooth-derived cells. In this study, we established a novel in vitro culture system with the use of undifferentiated dental mesenchymal cells from bovine bell-staged tooth germs and promoted differentiation of these cells into functioning odontoblasts. During the. 21-day culture period, the dental mesenchymal cells were exposed to 5 μg/ml ascorbic acid and 1 mM β-glycerophosphate (β-GP). These undifferentiated mesenchymal cells exhibited characteristics of odontoblasts at all stages of differentiation, starting from the immature stage to the terminal mineralization stage. Connective tissue growth factor (CTGF/CCN2) is a potent growth factor that regulates proliferation and differentiation of both chondrocytes and osteoblasts. Since CTGF is also expressed in differentiating preodontoblasts, we examined if CTGF can promote odontoblast differentiation. Recombinant CTGF (rCTGF), in the presence of ascorbic acid and β-GP, stimulated the expressions of the early odontoblast differentiation marker alkaline phosphatase (ALP) and collagen type I mRNA. In addition, the maturation markers osteopontin and dentin sialophosphoprotein (DSPP) mRNA were also expressed during the 9-day culture period. Histological and histochemical analyses confirmed that rCTGF, in the presence of ascorbic acid and β-GP, stimulated high alkaline phosphatase activity, calcium incorporation, and hydroxyapatite deposition. These findings demonstrated that our novel culture system can maintain the osteogenic potential of undifferentiated dental mesenchymal cells and promote their differentiation into functional odontoblasts. Furthermore, rCTGF is capable of promoting the differentiation of tooth germ mesenchymal cells into odontoblasts, suggesting that CTGF may be therapeutically useful in the future for promoting tooth regeneration.
We report a case of squamous cell carcinoma of the lower lip occurring on a hemangioma. A 79-year-old woman was referred to our hospital because an ulcer had developed on her swollen lower lip. She had a birthmark extending from both sides of the lower lip to the mental region and neck. The birthmark of the lower lip started to swell 15 years ago and grew gradually. She noticed an ulcer on the surface of her enlarged lower lip 6 months ago. A biopsy of the ulcer was performed, and the diagnosis was squamous cell carcinoma occurring on a heman-gioma. We carried out lower lip excision and reconstruction with a free forearm-palmaris longus flap under general anesthesia on May 15, 2000. Histopathological examination showed squamous cell carcinoma occurring on a cavernous hemangioma. There has been no evidence of recurrence or metastasis as of 2 years 11 months postoperatively.
Benign fibrous histiocytoma occurs predominantly on sun-exposed skin, and rarely arises in the oral cavity. A case of benign fibrous histiocytoma arising in the floor of the mouth is reported. A 67-year-old man was referred to our hospital because of a painless small mass on the right side of the floor of the mouth. Clinical examination revealed a papillary tumor 8 × 8 mm in diameter on the floor of the mouth. The clinical diagnosis was fibroma, and an excisional biopsy was performed. Microscopically, the surgical specimen consisted of uniform spindle-shaped cells arranged in a storiform pattern. There was no evidence of cellular atypia or mitotic figures. Immunohistochemically, the tumor cells were negative for actin (HHF-35) and CD34. The Ki-67 index was less than 10 %. On the basis of these findings, the tumor was diagnosed to be a benign fibrous histiocytoma. No recurrence has been noted as of 1 year after surgery.
A case of a large mucous cyst occurring in the buccal mucosa of a 27-year-old woman is reported. She visited the First Department of Oral and Maxillofacial Surgery, Kyushu Dental College Hospital because of a painless swelling on the left buccal mucosa. The lesion measured 19 × 26 mm and was a soft elastic mass covered with adipose tissue. The mass was located under the buccal mucosa of the left mandibular premolar region. The mass was not fixed to the surrounding tissue. We resected the mass under general anesthesia. A benign tumor was suspected. The mass had a thin outer capsule and was filled with fluid. We diagnosed the mass to be a mucous cyst during operation. The diagnosis was confirmed histopathologically. This was a rare case of mucous cyst with respect to the site of occurrence and size. At first, we strongly suspected that the mass was a benign tumor on the basis of the clinical and MM findings. Diagnosis was difficult because there were many similarities with other types of cysts and tumors in the affected region. Preoperative examinations such as computed tomography and ultrasonography besides MRI appeared to be necessary to evaluate the contents of the lesion.
Heterotopic gastrointestinal cyst (HGIC), also referred to as gastric cystic choristoma, is extremely rare in the oral cavity. We report a case of a gastrointestinal cyst in the oral floor of a 3-month-old boy. Viscous fluid, colorless and transparent, was aspirated, and marsupialization of the lesion was performed. The tissue was submitted for histopathologic evaluation. The cyst wall was lined by simple columnar epithelium resembling that of the gastric mucosa. Most gastrointestinal cysts arising in the oral cavity have occurred in the tongue and the floor of the mouth. The histogenesis of thisc yst is related to entrapment of undifferentiated, noncommitted endoderm within the oral cavity during the 4th-5th week of fetal life. The patient has had no evidence of recurrence for 4.5 years after marsupialization of the cyst.
Blue nevus is a type of nevus pigmentosus. In Japan, this condition of the oral mucosa is rare. We describe a patient with a blue nevus arising in the hard palate. A 21-year-old man consulted our department to undergo further examination of a painless pigmented spot on the hard palate. The lesion measured about 5 × 4 mm and bulged slightly. An X-ray film showed no internal bone resorption. Under local anesthesia, the lesion with the periosteum was resected. Pathologically, the lesion was diagnosed as a blue nevus. The postoperative course has been good, without relapse during 3 year of follow-up.
We report a case of bleeding after tooth extraction caused by an inhibitor of coagulation factor V. The patient was an 81-year-old man. After tooth extraction by a local dentist, the patient had uncontrolled bleeding from the socket and was referred to our hospital. Although we repeated curettage of the socket and sutured the gingival tissue, bleeding did not stop. He was then referred to the hematology department of our hospital. Close examination revealed an acquired inhibitor of blood coagulation factor VII. Bleeding was successfully controlled by recombinant activated factor VII. The patient was given steroids to suppress coagulation inhibitor production. Wound healing was uneventful.
Human butyrylcholinesterase (BChE) is an enzyme existing in plasma and liver that dissolves various choline-ester substrates. The serum cholinesterase level indicates the activity of BChE in serum. Low BChE activity is seen in patients with functional disorders of the liver, organic phosphorus exposure and hereditary serum BChE deficiency. In patients with low BChE activity, prolonged neuromuscular block is induced by the use of depolarizing muscle relaxants, such as succinylcholine for general anesthesia, or breathing trouble can be caused by the use of ester-form local anesthetics. We report a case of tongue fibroma in a 54-year-old man who had extremely low serum BChE activity. While monitoring the circulatory system, the tumor was resected with the use of an amino-form local anesthetic. Hypertension was seen before surgical treatment, possibly due to mental stress, and an antihypertensive was used. DNA sequencing analysis of the BChE gene in this patient revealed a homozygous missense mutation at nucleotide 1093, which resulted in GGA → CGA at Gly365Arg in exon 2.