KOREASCHOLAR

Plunging ranula is a mucous retention cyst with extension below to the mylohyoid muscle. It can occur by an extravasation of saliva from the salivary gland due to trauma or obstruction of the duct. Fluid from the obstructed gland penetrate through the defect of mylohyoid muscle or through the posterior edge of mylohyoid muscle, and spreading to the cervical area. The “tail sign” has been widely reported as pathognomonic for their diagnosis. It indicates the communication between the collapsed sublingual and submandibular space over the posterior edge of the mylohyoid muscle. In this case, in addition to simple ranula in the right floor of mouth, MRI findings showed homogeneous contrast enhancement in front of the right cervical carotid artery and in the deep part of sternocleidomastoid muscle, but tail sign was not observed. Therefore it was clinically diagnosed as a branchial cleft cyst and was removed through surgical procedure. As a result of the final pathologic biopsy, the lesion, which has been suggested to be simple ranula in the floor of mouth, was diagnosed as reactive pyogenic granuloma, and the cervical lesion was diagnosed as a plunging ranula. This is a case report in which these two lesions are decided to have been separated from one before surgery. This report indicate that plunging ranula can be observed without tail sign and how to make an accurate diagnosis of plunging ranula by reporting misdiagnosis case.

Abstract
Ⅰ. INTRODUCTION
Ⅱ. CASE REPORT
Ⅲ. DISCUSSION
Ⅳ. CONCLUSION
REFERENCES

• 오태경(연세대학교 치과대학 구강악안면외과학교실) | Tae-Gyeong Oh (Department of Oral & Maxillofacial Surgery, Yonsei University College of Dentistry)
• 차인호(연세대학교 치과대학 구강악안면외과학교실) | In-ho Cha (Department of Oral & Maxillofacial Surgery, Yonsei University College of Dentistry)
• 한승용(연세대학교 치과대학 구강병리학교실) | Seung-Yong Han (Department of Oral pathology, Yonsei University College of Dentistry)
• 조은애산드라(연세대학교 치과대학 구강병리학교실) | Eunae Cho (Department of Oral pathology, Yonsei University College of Dentistry)
• 남웅(연세대학교 치과대학 구강악안면외과학교실) | Woong Nam (Department of Oral & Maxillofacial Surgery, Yonsei University College of Dentistry) Corresponding author