病棟実習の代替教育ツールとしての オンライン方式JABSOM PBLの実践 ～横浜市立大学医学部における試み～ Practice of online method JABSOM PBL as an alternative medical educational tool in a hospital -An attempt at Yokohama City University School of Medicine

新型コロナウイルス感染症拡大に伴い，オンライン方式での医学教育の必要性は日々増しており，より効果的な医学教育の方略が模索されている．当教室では，ハワイ大学（John A. Burns School of Medicine：JABSOM）において実践されている problem based learning（PBL）（JABSOM PBL）を病棟実習の一部として2019年度より導入しており，さらにコロナ禍において，オンライン方式に改良し，病棟実習の代替教育ツールとして実施している．本稿では，オンライン方式JABSOM PBLの詳細と通常のPBLとの相違点および今後の課題について概説する

A case of Giant Chondrosarcoma in the Middle Fossa

Chondromas and chondrosarcomas are rare cranial tumors that are reported to have similar clinical presentations and radiological features, but need to be treated differently. 36-year-old female, complaining of vertigo and morning headaches presented at our hospital, but had no neurological deficits. After completing a series of MRI scans, a giant tumor was evident in the middle fossa. As noted, chondromas and chondrosarcoma are radiologically very similar, if not identical, in appearance. In this case, the tumor was in fact initially diagnosed as a chondroma by histological staining, but after further examination of specimens, the diagnosis was revised, and finally found to be a chondrosarcoma. None of the MRI or CT features of these tumors appear to be useful for differentiating chondoromas from chondrosarcomas preoperatively. The former typically consists of normal cells. While the latter is generally able to be diagnosed due to the presence of either necrotic cells or cells while dividing nuclease. However, diagnosis can be very difficult due to the low number of irregular cells. Treatment in both cases typically involves resection or removal of the tumor. Due to the malign not use of the chondrosarcoma, radiotherapy or chemotherapy is undertaken after the operation. Given the radiological similarity of these two tumors, we should rely not only on diagnosis from MRI