Ranulas are mucous cysts that arise from the sublingual gland due to ductal obstruction or trauma. Plunging ranulas, a rare variant, extend into the neck and often present diagnostic challenges. Definitive surgical management is necessary to prevent recurrence and ensure successful outcomes.

A 20-year-old female presented with a slowly enlarging, painless mass in the floor of her mouth extending into the submandibular region and anterior neck. The mass had progressively increased in size over five years, affecting her appearance and mastication. MRI confirmed a large plunging ranula. The patient underwent complete surgical excision of the cyst and the sublingual gland under general anesthesia. She recovered well, with no immediate postoperative complications. Follow-up at 12 months showed no recurrence, and the patient reported full resolution of symptoms.

This case highlights the importance of early recognition and accurate diagnosis of plunging ranulas to guide appropriate surgical intervention. Complete excision of the sublingual gland remains the treatment of choice for preventing recurrence. In line with similar cases in the literature, this approach resulted in a successful outcome with no evidence of recurrence during follow-up. The findings underscore the clinical significance of individualized treatment strategies based on the extent of anatomical involvement.