Biomedical subjects

Yutaka Koga

Publications and source records attributed to Yutaka Koga.

5 recordsLinked to original sources

PubMed2006

Complete extirpation of a bronchogenic cyst causing recurrent laryngeal nerve palsy by thoracoscopy: report of a case.

We excised a bronchogenic cyst causing recurrent laryngeal nerve palsy using thoracoscopic surgery. A 28-year-old woman presented after the sudden onset of hoarseness, and laryngoscopic examination showed left vocal cord palsy. Computed tomography and magnetic resonance imaging showed a cystic mass, 4 cm in diameter, in the aortopulmonary window. Thoracoscopic examination revealed that the mass was adhered to the recurrent laryngeal nerve below the aortic arch. We extirpated the cyst via thoracoscopy without any injury to the nerves or major blood vessels. This case illustrates the benefits of thoracoscopic surgery for providing good visualization of the perineural structures and as a safe surgical treatment for a cystic mass in the aortopulmonary window.

Adult↗

PubMed2006

Metachronous mature cystic teratomas in the left ovary and bilateral diaphragm: Report of a case.

Mature cystic teratomas are found often in gonadal sites, but rarely in extragonadal sites, such as the retroperitoneum, mediastinum, central nerve system, lung, and liver. To our knowledge, only seven cases of pathologically benign mature cystic teratoma originating in the diaphragm have been reported. We report the case of a 45-year-old woman found to have a mature cystic teratoma below the left side of her diaphragm. She had undergone oophorectomy for a huge mature cystic teratoma in the left ovary 34 years earlier, followed 1 year later by excision of a tumor in the right side of the diaphragm. All sections of the pathological specimen showed evidence of a mature cystic teratoma and pathologically resembled the specimens obtained in the previous two operations. Although this tumor might have been a recurrence of the mature cystic teratoma in the left ovary, it is more likely that multicentric teratomatous foci metachronously developed in the gonadal and extragonadal sites.

Diagnosis, Differential↗

PubMed2005

Thyroid evaluation in patients with primary hyperparathyroidism.

We evaluated the efficacy of preoperative high-resolution ultrasonography (US) for diagnosing possible concomitant thyroid disease which affects the surgical management in patients with primary hyperparathyroidism (pHPT). One hundred and nine patients with sporadic pHPT underwent US with or without ultrasound-guided fine-needle aspiration biopsy (US-FNAB). Diagnosis of concomitant thyroid nodules by US and US-FNAB were compared with the histopathological findings. Of the 109 patients, 19 (17.4%) had malignant thyroid nodules, 26 (23.9%) had benign thyroid nodules alone, and 12 (11.0%) had diffuse goiter. The sensitivity, specificity, and accuracy of diagnosing 72 thyroid nodules were 91.3%, 91.8%, and 91.7% for US, 57.9%, 94.3%, and 81.5% for US-FNAB, and 95.7%, 91.8%, and 93.1% for combined US and US-FNAB, respectively. True positive/false negative ratio of US-FNAB diagnosis was significantly lower in nodules of 5-9 mm than nodules of 10 mm or more. Four unexpected thyroid cancers existed at a different site in 3 of the 39 patients with palpable thyroid disease. Five thyroid cancers were histopathologically confirmed in 5 (7.1%) of 70 patients without palpable thyroid disease. Eight (88.9%) of the 9 non-palpable thyroid cancers were accurately diagnosed by combined US and US-FNAB. Preoperative US is useful for evaluation of possible concomitant thyroid disease, especially for prediction of malignancy.

Adenoma↗

PubMed2002

Vitamin D status in Japanese patients with hyperparathyroidism: seasonal changes and effect on clinical presentation.

The disturbance of vitamin D metabolism plays an important role in determining the clinical presentation of hyperthyroidism. We studied 72 patients (65 women, 7 men) with primary hyperparathyroidism (pHPT). Clinical presentation, biochemical indices, and bone mineral density (BMD) were compared in three patient groups classified according to their serum 25-hydroxyvitamin D (25OHD) levels: 23 patients whose 25OHD level was <25 nmol/L comprised the low group, 26 whose level was 25 to 40 nmol/L made up the intermediate group, and 23 whose level was > 40 nmol/L comprised the high group. The mean serum calcium level was 10.8 +/- 0.9 mg/dl, and the mean weight of the resected parathyroids was 684 +/- 749 mg. The mean serum 25OHD level was 36.5 +/- 16.3 nmol/L (normal 25-100 nmol/L). Levels were below normal in 23 patients (32%). No between-group differences existed for clinical presentation, biochemistry, or BMD. Only differences in mean patient age were statistically significant between groups. Vitamin D deficiency is common among Japanese patients with pHPT, but the effects of HPT on clinical, biochemical, and densitometric indices are not pronounced. Our study population was at an early stage of pHPT, so the vitamin D deficiency may not be associated with the effects of HPT.

Adult↗

PubMed2002

Autoimmune pancreatitis starting as a localized form.

Autoimmune pancreatitis is a rare type of pancreatitis that is characterized by diffuse swelling of the pancreas and irregular stenosis of the pancreatic ductal system ("sclerosing" pantreatitis), caused by autoimmune processes. Previous reports have shown the complete form of the disease, but very few have presented follow-up imagings from the beginning to the complete form. We, herein, report a case of autoimmune pancreatitis starting as a localized form. A-56-year-old Japanese man developed obstructive jaundice. Ultrasonography showed a hypoechoic mass in the head of the pancreas, and endoscopic retrograde pancreatography (ERP) showed localized stenosis of the pancreatic duct in the head of the pancreas. Computed tomography (CT) showed enlargement, with a capsule-like rim, in the head of the pancreas. Internal biliary tube drainage was performed to relieve the obstructive jaundice. The patient was followed-up under the tentative diagnosis of localized "mass-forming" pancreatitis. Four months after the drainage, CT showed diffuse swelling of the pancreas, with a capsule-like rim, and ERP demonstrated diffuse irregular narrowing of the pancreatic duct. Glucose intolerance was noted for the first time. Steroid was given as a diagnostic treatment for autoimmune pancreatitis. Two months after initiation of the steroid treatment, the ERP findings were normal, and CT showed a normal pancreas. The biliary tube was removed, and the glucose intolerance was subsequently alleviated. To summarize, we report a case of autoimmune pancreatitis starting as localized "mass-forming" pancreatitis with a peripheral rim on imagings. It is very important to be well aware of the presence of the localized form of autoimmune pancreatitis.

Autoimmune Diseases↗