A Large Cystic Lesion of the Hard Palate Extending to the Maxilla: A Case Report

Significance Statement

Hard palate cysts are relatively uncommon, requiring consideration of several potential differential diagnoses, such as nasopalatine duct cysts, radicular cysts, and primary or secondary mucoceles. Endoscopic trans-nasal marsupialization is a safe and cost-effective treatment option for hard palate cysts, with low rates of recurrence and complications. Here, we present the clinical characteristics, differential diagnosis, and treatment modalities for cystic lesions of the hard palate.

Rhinoscopic Clinic

An 18-year-old man presented to our hospital with a chief complaint of right-side facial swelling. He did not experience any associated facial pain or tenderness; moreover, he had no relevant medical or trauma history. Endoscopic examination revealed swelling in the hard palate, without specific findings in the nasal cavities. Computed tomography (CT) and magnetic resonance imaging revealed a well-defined cystic lesion (5.9 cm × 3.0 cm × 2.5 cm) in the hard palate, extending to the right maxilla and nasolabial fold. Moreover, bony erosion of the hard palate and right maxilla was observed (Figure 1A and B).

Figure 1.

Preoperative findings. (A) Coronal view on computed tomography reveals a well-defined cystic lesion in the hard palate, extending to the right maxillary sinus. (B) Coronal T2-weighted magnetic resonance imaging shows the same cystic lesion.

The patient underwent endoscopic trans-nasal marsupialization while under general anesthesia. A small perforation was made at the roof of the cyst on the right nasal floor using a seeker. Subsequently, the opening was enlarged using various cutting forceps, and the margins were trimmed using a microdebrider. The cyst, containing dark brown fluid, was aspirated via suction and cleaned by saline irrigation.

A sample of the epithelial lining within the cyst was obtained and sent for histological examination. However, the examination only revealed nonspecific inflammatory findings, and a definitive diagnosis could not be established. At 1 month post-surgery, endoscopic examination demonstrated an enlarged opening with a completely epithelialized edge. Subsequently, follow-up CT revealed a clear cyst cavity (Figure 2A). Additional follow-up examinations revealed no signs of recurrence within 12 months post-surgery (Figure 2B). Notably, the patient did not report any symptoms related to the accumulation of nasal secretions within the cyst (Figure 2C).

Figure 2.

Postoperative findings. (A) Follow-up computed tomography 4 weeks after surgery shows a clear cyst cavity with mild mucosal thickening. (B) Endoscopic view 12 months after surgery, showing no signs of recurrence. (C) Clear cyst cavity is observed under the 70° endoscopes 12 months after the procedure.

Cystic lesions of the hard palate are relatively uncommon and typically regarded as maxillary cysts.^1,2 These benign lesions are classified as odontogenic and non-odontogenic cysts based on the 1992 World Health Organization guidelines. ³ Radicular and nasopalatine duct cysts are the most common types of odontogenic and non-odontogenic cysts, respectively. ⁴

Usually asymptomatic, hard palate cystic lesions are often incidentally found through radiological imaging or physical examinations. However, these lesions can cause symptoms such as facial or hard palate swelling, pain, and discharge; the presence and severity of these symptoms are associated with the size, location, and inflammatory status of the lesions. ¹

Despite their diverse origins, these cystic lesions exhibit similar clinical features. ³ Therefore, radiological examinations play a key role in differential diagnosis. Notably, hard palate cysts are characterized by well-defined round or oval-shaped lesions; the degree of displacement of adjacent structures depends on the size of these cysts.^1,4

Surgical resection through a trans-oral or trans-nasal approach is the recommended treatment for hard palate cystic lesions because of its low recurrence rate. However, it can be time-consuming and is associated with complications, such as oroantral fistula, loss of dental components, hematoma, and wound infection.^2,5,6 Since the introduction of endoscopic trans-nasal marsupialization in 1999, ⁷ this technique has become a primary treatment option, particularly for large cysts, due to its simplicity and safety.

In our study, although the results of histologic examination did not support a definitive diagnosis, a non-odontogenic origin was suspected due to the absence of tooth root invasion on CT. However, the possibility of other cystic lesions, such as radicular cysts, mucoceles, or developmental abnormalities, should be considered. We have presented the clinical findings, differential diagnosis, and treatment modalities for hard palate cystic lesions, providing insights for rhinologists who encounter similar cases in clinical practice.