Kenichi Nakamura

A Japanese family showing high-frequency hearing loss with KCNQ4 and TECTA mutations.

Abstract Conclusions: We describe a Japanese family with high-frequency sensorineural hearing loss (SNHL) harboring a c.211delC mutation in the KCNQ4 gene. Families showing progressive high-frequency SNHL should be investigated for mutations in the KCNQ4 gene. Objective: To determine the responsible deafness gene in a Japanese family with dominantly inherited high-frequency SNHL of unknown etiology. Methods: We performed hearing tests for five members of the family, and the three affected with hearing loss underwent further audiological and vestibular examinations. Genetic analysis was performed to identify any possible causative mutations, as well as analysis of detailed clinical findings to determine the phenotype. Results: The three affected subjects showed high-frequency SNHL. Extensive audiologic evaluation suggested cochlear involvement and progressive hearing loss. As for bilateral caloric testing, two of the three affected subjects showed hyporeflexia with recurrent vestibular symptoms. We identified the c.211delC mutation in the KCNQ4 gene and the c.2967C>A (p.H989Q) mutation in the TECTA gene. Based on the genotype–phenotype correlation, the c.211delC mutation in the KCNQ4 gene was associated with high-frequency SNHL in this family.

POU4F3 mutation screening in Japanese hearing loss patients: Massively parallel DNA sequencing-based analysis identified novel variants associated with autosomal dominant hearing loss

A variant in a transcription factor gene, POU4F3, is responsible for autosomal dominant nonsyndromic hereditary hearing loss, DFNA15. To date, 14 variants, including a whole deletion of POU4F3, have been reported to cause HL in various ethnic groups. In the present study, genetic screening for POU4F3 variants was carried out for a large series of Japanese hearing loss (HL) patients to clarify the prevalence and clinical characteristics of DFNA15 in the Japanese population. Massively parallel DNA sequencing of 68 target candidate genes was utilized in 2,549 unrelated Japanese HL patients (probands) to identify genomic variations responsible for HL. The detailed clinical features in patients with POU4F3 variants were collected from medical charts and analyzed. Novel 12 POU4F3 likely pathogenic variants (six missense variants, three frameshift variants, and three nonsense variants) were successfully identified in 15 probands (2.5%) among 602 families exhibiting autosomal dominant HL, whereas no variants were detected in the other 1,947 probands with autosomal recessive or inheritance pattern unknown HL. To obtain the audiovestibular configuration of the patients harboring POU4F3 variants, we collected audiograms and vestibular symptoms of the probands and their affected family members. Audiovestibular phenotypes in a total of 24 individuals from the 15 families possessing variants were characterized by progressive HL, with a large variation in the onset age and severity with or without vestibular symptoms observed. Pure-tone audiograms indicated the most prevalent configuration as mid-frequency HL type followed by high-frequency HL type, with asymmetry observed in approximately 20% of affected individuals. Analysis of the relationship between age and pure-tone average suggested that individuals with truncating variants showed earlier onset and slower progression of HL than did those with non-truncating variants. The present study showed that variants in POU4F3 were a common cause of autosomal dominant HL.

Primary Pleomorphic Adenoma of the External Auditory Canal: A Case Report and Review of the Literature

Background. Pleomorphic adenoma (PA) is a benign tumour that mainly arises from salivary glands, and PA of the external auditory canal (EAC) is very rare. The objective of this study was to clarify the clinical presentation and treatment of PA of the EAC. Method. The authors present a case of PA arising from the EAC together with a literature review. Results. A 40-year-old man complained of hearing loss and foreign-body sensation of the right ear. Clinical and radiological examinations revealed a well-defined tumour limited to the EAC, with no connection to the parotid gland. Preoperative fine-needle aspiration cytology findings were characteristic of PA. The tumour was removed en bloc with the overlying skin. Conclusion. PA of the EAC is very rare, and methods to rule out malignancy before treatment are lacking. Thus, long-term follow-up is necessary, because malignant tumours are common in the EAC and PA has malignant potential.

A Melanocytic Lesion Extending From the Right Ear to the Nasopharynx in a Pediatric Patient: A Case Report

Background: Blue nevus is a benign dermal melanocyte tumor that mainly arises from the skin. We report an extremely rare case of blue nevus in a pediatric patient with extensive progression from the middle ear and inner ear to the nasopharynx through the Eustachian tube. Case Report: A 2-year-old girl with blue tympanum was referred to our department. Computed tomography scans and magnetic resonance imaging were performed, followed by a tissue biopsy and histopathologic evaluations. Radiologic examinations revealed that the lesion had progressed beyond the middle ear into the inner ear and the nasopharynx through the Eustachian tube. Subsequent histopathologic examinations indicated dermal dendritic melanocytic proliferations, but no evidence of malignancy. Based on the clinical and histopathologic findings, we concluded that the lesion was consistent with blue nevus. Discussion: Blue nevus is a relatively common skin lesion. However, no prior reports have described the extension of blue nevus from the auditory organ to the nasopharynx in a pediatric patient. Despite the benign nature of the lesion, the patient experienced profound hearing loss in the affected ear, which necessitates continued monitoring as the lesion may expand with patient growth.

Usefulness of reconstructed 3D images for cochlear implantation in a case with a facial nerve anomaly

Facial nerve anomalies are a potential problem in patients with cochleovestibular malformations. A case of cochlear implant (CI) surgery in the presence of intra-temporalbone facial nerve bifurcation is presented. During the first surgery, the facial nerve bifurcation obscured the promontory and round window. It was difficult to perform cochleostomy because of the lack of landmarks of the basal turn of the cochlea, and the first surgical attempt at cochleostomy was abandoned. A repeat CT scan was performed after the first surgery with reconstructed 3D images of the temporal bone and the cochlea, and then the cochlea was successfully opened at revision surgery. Reconstructed 3D CT images were very useful to identify the site of cochleostomy in this case with such difficult temporal bone anatomy.

Retroperitoneal and Mediastinal Pancreatic Pseudocyst Accompanied by Pancreas Divisum

症例は 68歳のアルコール多飲歴のある男性で,呼吸困難を主訴に近医を受診し,右胸水貯留を指摘さ れ,当院紹介となった.当院初診時の単純 CTで右胸水貯留に加え,後腹膜から縦隔内の低吸収域,膵石 を認めた.胸水中のアミラーゼは高値であった.胸水ドレナージ後の造影 CTで,後腹膜から縦隔内の低 吸収域は囊胞性病変と判断した.また,膵体尾部頭側には膵仮性囊胞を認めた.以上から,慢性膵炎に伴 う,後腹膜・縦隔内膵仮性囊胞と診断した.膵管癒合不全のため,ERCPで縦隔内,肝背側囊胞への内瘻 を描出できなかったが,MRCPでは膵体尾部頭側の囊胞から後腹膜囊胞への内瘻の存在を疑った.脾合併 膵体尾部切除術を施行し,術後 4か月の CTでは後腹膜,縦隔内囊胞は消失した.膵管癒合不全のため, 縦隔内膵仮性囊胞への内瘻が ERCPで確認困難な症例であったが,MRCPではその存在を疑うことがで き,治療方針の決定に有用であった.

A case report of malignant lymphoma in the accessory parotid gland

The accessory parotid gland is independent of the parotid gland. In the present case, a 43-year-old man was referred to our hospital for further investigation of a mass in his right cheek. A malignant tumor was suspected and it was excised. The tumor arose from the accessory parotid gland and the pathological diagnosis was follicular lymphoma. The rate of occurrence of malignant tumors in the accessory parotid gland is higher than in the parotid gland. A malignant tumor in the accessory parotid gland should be suspected when there is a mass in the cheek. The tumor was suspected of being a malignant lymphoma which arose from the accessory parotid gland because the first clinical manifestation of the disease was involvement of the salivary gland and there was no lymph node near the accessory parotid gland tumor.

A case of congenital unilateral facial nerve aplasia

Abstract The most frequent cause of unilateral congenital facial paralysis is birth injury, and this injury recovers completely within several weeks. On the other hand, congenital facial paralysis due to facial nerve aplasia is irreversible. After a normal pregnancy and a smooth cesarean section, a 2-month-old girl presented with left facial paralysis. Grading of her facial paralysis was House–Brackmann Grade V and Sunnybrook Grading Score 9. She was diagnosed with complete congenital unilateral facial paralysis. The facial nerve aplasia diagnosis was observed with magnetic resonance imaging and computed tomography. Three-dimensional constructive interference in steady state magnetic resonance imaging and high-resolution computed tomography scanning are very useful for diagnosing congenital facial paralysis due to anatomic anomalies. Facial nerve aplasia has been considered a very rare condition, but it is likely a more frequent diagnosis in cases with irreversible congenital facial paralysis.