Cytology is one of the useful pathological examinations for oral lesions. Recently, liquid-based cytology is used instead of conventional smear cytology because it offers several advantages over the conventional method in cytological diagnosis. Furthermore, liquid-based cytology specimens can be applied to immunohistochemical and molecular analyses. This review summarizes the use of liquid-based cytology for oral diseases, along with possible applications for immunohistochemical and molecular diagnosis.

View full abstract

Dysfunction in the oral cavity caused by drugs, such as taste disorder and xerostomia, may affect a patient’s life. In the future, the number of patients with drug-induced taste disorder who have multiple diseases is expected to increase due to the aging of society. In order to clarify the condition of drug-induced taste disorder in dentistry, we compared it with past reports and conducted an analysis, including an overview. It is important for dentists to identify the cause of taste disorder and provide appropriate medical care.

View full abstract

Taste disorder in the anterior two-thirds of the tongue is caused by injury to the chorda tympani nerve （CTN）. We report a case of taste disorder following surgery for otitis media caused by middle ear cholesteatoma （MEC）. A female in her 60s presented to our department with persistent dysgeusia since dental treatment. A taste test, electrogustometry （EGM） and the filter paper disc method （FPD） revealed the taste disorder only in the unilateral CTN area. Although she insisted that the dysgeusia was associated with dental treatment, a detailed dental examination and history of dental diseases revealed no abnormalities. A detailed medical interview revealed that she had undergone ear surgery around the same time as dental treatment. Surgical and imaging findings provided by an otolaryngologist indicated that she had received surgery for otitis media following MEC that had caused CTN dysfunction. During prolonged follow-up, dysgeusia showed a better correlation with FPD than EMG. FPD may be useful for assessing dysgeusia caused by injury to CTN. Dentists should pay close attention to dental treatment and cooperate with an otolaryngologist when middle ear surgery is undergone at the same time.

View full abstract

Schwannoma is a benign tumor originating from Schwann cells, occurring rarely in the masseter muscle. In this report, we describe a case of schwannoma in the masseter muscle. A 35-year-old man was referred to our hospital because of swelling of the left cheek. A painless elastic hard mass was palpable in the left cheek. No abnormalities were found in the skin, oral mucosa, or cervical lymph nodes. MRI T2-weighted images showed a high signal area with 43×37mm internal nonuniformity and clear boundaries. Although malignant atypical cells were not detected by fine-needle aspiration and incisional biopsy, no definitive diagnosis was obtained. The lesion was diagnosed as a benign tumor of the masseter muscle and resection was performed under general anesthesia. It was located in the masseter muscle without any adhesion to surrounding tissues. No nerves were continuous with the tumor. The tumor was 45×40×30mm in size and was covered with a capsule. Histopathological diagnosis was schwannoma. After the operation, left facial nerve palsy was recognized, but it was completely cured 3 months after the operation. In addition, neither masseter atrophy nor masticatory function was observed. Two years have passed since the operation without recurrence of the tumor.

View full abstract

Neurofibroma is a benign peripheral nerve sheath tumor consisting of an admixture of Schwann cells, fibroblasts, perineurial-like cells, and axons. It is usually considered as a part of neurofibromatosis type-1 （von Recklinghausen disease）. Solitary neurofibroma is an uncommon tumor of the oral and maxillofacial region. A man in his 40s was referred to our hospital with the chief complaint of a mass in the right cheek. Physical examinations revealed a well-defined, elastic-soft, mobile, painless 25-mm mass in the cheek. Ultrasonography revealed a hyperechoic mass with clear borders, internal nonuniformity, and a low blood flow signal. Magnetic resonance imaging revealed that the mass was adjacent to the masseter muscle, and had a relatively homogenous and equal signal intensity with the muscle on T1-weighted image, and high signal intensity on T2-weighted image. The tumor was surgically resected under general anesthesia. Microscopic examination showed random rearrangement of spindle cell proliferation, and positive immunostaining for the S-100 protein and CD34. The tumor was diagnosed as a neurofibroma. Neither café au lait spots nor other tumors were observed on physical examination. The final diagnosis was solitary neurofibroma arising in the cheek. Three years after the surgery, the patient showed no signs of tumor recurrence.

View full abstract

Lateral periodontal cyst （LPC） can rarely cause a loss of cortical bone in the jaws. We report cases of LPC and odontogenic keratocyst that showed similar clinical findings. Case 1 involved a 70-year-old woman who presented with gingival swelling in the right mandibular molar region. CT showed clear bone resorption in the right mandibular molar region, absorption of buccal cortical bone, and progression of the lesion beyond the bone. Cystectomy was performed under local anesthesia. Pathological findings revealed clear cells, and LPC was diagnosed. Case 2 involved a 40-year-old man who presented with gingival swelling in the lower premolar region. Buccal cortical bone of the right mandible absorbed on CT, and the lesion that resorbed the buccal cortical bone spread to surrounding soft tissues. Cystectomy was performed under general anesthesia. Pathological findings revealed lining epithelium comprising thin, parakeratotic, stratified squamous epithelium and columnar cells arranged in a palisade pattern in the basal layer. As of 2 years 6 months and 2 years 2 months postoperatively, respectively, neither case showed any evidence of recurrence.

View full abstract

Arteriovenous malformations （AVM） are vascular malformations, characterized by direct communication between arteries and veins, lacking a normal capillary network. We describe a rare case of AVM of the lower lip. A woman in her 60s was referred to our department because of swelling and contact pain of the lower lip. The size of the lesion was that of the little finger, the head was large, and pulsation was felt on palpation of the lip. The lesion was preoperatively diagnosed as AVM by computed tomography angiography （CTA）, magnetic resonance imaging （MRI） and digital subtraction angiography （DSA）. Though we planned to perform surgical resection following endovascular embolization, it seemed to be difficult to embolize the right facial artery （feeding artery） because the artery was highly tortuous. Therefore, we ligated it and resected the AVM. Recurrence has not occurred as of about 4 years after surgery.

View full abstract

Resection of maxillary malignant tumors frequently extends from the oral cavity to the maxillary sinus and to the nasal cavity. The defects caused during resections are restored using dento-maxillary prostheses. However, in some cases, support for and stability of the prostheses cannot be achieved, leading to influx of water and food fragments into the maxillary sinus and nasal cavity. The present report describes patients in whom buccal fat pad transplantation was performed to treat oroantral and oronasal fistulas formed after partial maxillary resection. Among the patients diagnosed with maxillary gingival cancer and palatal cancer at the authors’ hospital department between May 2012 and July 2020, eight elderly patients with complicating diseases were selected as the subjects for the present study. For all eight patients, buccal fat pad transplantation was performed to treat post-resection oroantral and oronasal fistulas, with immediate closure of the fistulas postoperatively. The post-transplantation outcome showed complete closure of the fistulas in five subjects, and partial closure in three subjects. The partial dentures were stable in all subjects, and the invasiveness of the surgery was low. Therefore, this method could be useful to treat elderly people with complicating diseases.

View full abstract

Necrotizing sialometaplasia is a rare benign lesion that is characterized by squamous metaplasia, necrosis, and inflammation of the salivary glands. Clinically and histopathologically, differential diagnosis is necessary because it is similar to squamous cell carcinoma or mucoepidermoid carcinoma. In this report, the clinical course of a necrotizing sialometaplasia in the hard palate is described. A 22-year-old woman was referred to our department with complaints of swelling and pain of the left palate. A swollen lesion, 30×20mm in diameter, with a crater-like ulceration was observed in the posterior part of the left hard palate. A biopsy was performed and the histopathological diagnosis was necrotizing sialometaplasia. After 2 months, the lesion spontaneously healed without any medical treatment.

View full abstract

We report a case of schwannoma of the left lower lip in a 17-year-old female. A schwannoma is a tumor thought to be derived from Schwann cells and is rarely seen in the lip. On initial visual and palpation examination, a nodular, elastic hard, mobile mass was found on the left lower labial mucosa, which was suspected to be a benign tumor. Contrast-enhanced magnetic resonance imaging （MRI） showed a homogeneous contrast effect on T1-weighted images, negating malignant findings. Aspiration cytology showed no atypical cells. There was no rapid growth of the tumor during follow-up. The patient was diagnosed as having a benign tumor of the lower lip and the tumor was enucleated under local anesthesia. The pathological diagnosis was an Antoni A-type schwannoma. The patient is progressing well with no postoperative motor or sensory deficits.

View full abstract

Intravascular papillary endothelial hyperplasia is an intravascular lesion characterized by the papillary proliferation of endothelial cells, and is rarely seen in the oral region. We present a case of intravascular papillary endothelial hyperplasia in a 21-year-old man. Physical examination revealed an elastic and slightly hard, dark purple swelling, measuring 8×7mm, on the left side of the dorsum of the tongue, and resection was performed under the clinical diagnosis of hemangioma. Postoperative pathological examination revealed papillary proliferation of endothelial cells close to the thrombus in a large single blood vessel. Based on these findings, the case was diagnosed as a pure form of intravascular papillary endothelial hyperplasia. The postoperative course was uneventful without recurrence for four years.

View full abstract

We report two cases of impacted mandibular second molars. Case 1: A 25-year-old woman presented to our hospital upon being referred by her family dental clinic. A panoramic X-ray revealed complete impaction of the bilateral mandibular second molars. As the patient preferred orthodontics, the bilateral mandibular second molars were treated via the open technique and intra-oral elastic traction. Two years after the surgery, the right mandibular second molar was upright, but the left mandibular second molar became unsalvageable and was extracted. The patient continues to use full arch orthodontics. Case 2: A 16-year-old man presented to our hospital with delayed eruption of the left mandibular second molar. A panoramic X-ray revealed horizontal impaction of the left mandibular second molar. The axis of the molar was tilted buccolingually and eruption was difficult. According to the patient’s wishes, the left mandibular second molar was extracted at the referral hospital. There are various treatment plans for treating an impacted tooth, such as tooth extraction, replantation, and making upright. Long-term neglect of an impacted mandibular second molar may cause malocclusion that might be unexpected by the patient. Therefore, it is suggested that early diagnosis and treatment of an impacted mandibular second molar might be necessary.

View full abstract

Lipomas are the most common type of benign tumor and frequently occur in the head and neck region. The clinical course may develop over a period of years in the form of a gradually enlarging, painless mass. We report a relatively uncommon case of lipoma of the buccal region with penetration of the facial artery in the tumor. We conducted preoperative imaging based on previous reports and suggest that the combination of ultrasonography and magnetic resonance imaging might be necessary for proper diagnosis and treatment.

View full abstract

Myelodysplastic syndrome （MDS）, an acquired hematopoietic disorder that is commonly referred to as preleukemia, often manifests as refractory anemia. Patients with this condition undergoing dental procedures may exhibit a bleeding tendency because of pancytopenia, infection, etc., necessitating a cautious approach. A man in his 70s presenting with upper left buccal swelling was referred to our department for detailed examination and treatment.
Based on X-ray and CT findings （diagnostic imaging）, the patient was diagnosed as having left upper phlegmon, caused by a periapical lesion of the maximally left second molar. Further, the results of several laboratory examinations led to the suspicion of a systemic disease, and so the patient was referred to the hematology department; a bone marrow puncture was performed and the patient was diagnosed as having MDS. Thirteen teeth extractions and two pulp extractions were performed under local anesthesia, under cover of platelet transfusions during hospitalization.
The patient, who was diagnosed with MDS due to an odontogenic infection, received successful dental treatment in cooperation with the hematology department, and good results were obtained.

View full abstract

Gender identity disorder （GID） is defined as “a condition in which biological gender （sex） does not match gender self-consciousness or gender identity.” One of the main symptoms is “dislike or avoidance of one’s gender.” That is, GID patients will want to acquire physical characteristics that are closer to their gender identity. Facial morphology centered on the maxilla and mandible is one such characteristic. The present case was a 51-year-old man. He visited Tokyo Dental College Suidobashi Hospital with the chief complaint of “wishing to improve prognathism and facial asymmetry”. We started surgical orthodontic treatment to improve the patient’s occlusion and facial esthetics, but along the way, it turned out that the patient was being treated for GID. As orthognathic surgery, Le Fort Ⅰ osteotomy and sagittal split ramus osteotomy were performed to improve facial asymmetry and mandibular prognathism. The patient then underwent sex reassignment surgery （SRS） abroad. The patient is continuing to visit our hospital. Here, we report on considerations when planning orthognathic surgery for GID patients, which is expected to increase in the future.

View full abstract