Cystadenoma is an uncommon benign epithelial neoplasm. Cystadenoma usually occurs on the palatal and buccal mucosa, but is less commonly found in the retromolar regions.A 43-year-old male patient noticed a swelling on his gingiva distal to the right mandibular second molar. Physical examination showed a diffuse poorly circumscribed swelling extending from the lingual gingiva distal to the right mandibular second molar to the floor of the mouth and pharynx. The tumor size was 20 x 27 mm. The surface mucosa was purply-blue in parts. About 4 ml of pale yellow serous fluid was aspirated. The tumor was surrounded by a capsule and was excised successfully above the periosteum, incorporating a 2 mm safety margin including the surface mucosa. The tumor consisted of a fibrous capsule with multiple cystic cavities of various sizes. The cysts were lined by a layer of columnar epithelium, with intracystic papillary proliferation in some areas. No cytologic atypia or invasion of the surrounding tissues were observed.There is no evidence of recurrence ten years after excision, suggesting that complete excision is sufficient treatment in such cases.

A 61-year-old man with consciousness disorder was transferred to our hospital. Computed tomography found acute type A aortic dissection and cardiac tamponade, and an emergency operation was performed. Operation findings indicated dissection above the commissure between the left coronary cusp and the right coronary cusp, to the ostium of the right coronary. An ascending aorta replacement and coronary aorta bypass grafting were performed. The postoperative course was good, but he did not regain clear consciousness. Results of magnetic resonance imaging showed multiple cerebral infarctions. At the same time, the platelet count had decreased and we suspected heparin-induced thrombocytopenia (HIT). Following detection of an heparin-dependent antibody, administration of an heparin was discontinued. However, the platelet count still tended to decrease. Therefore, we started continuous administration of argatroban, which resulted in the gradual increase in platelet count to within normal limits on postoperative day 26. The results indicate that in patients continuously and repeatedly treated with heparin, there is a possibility of the development of HIT and thrombosis with HIT.