Mucous Gland Cyst in the Uncinate Process: A Comprehensive Case Study and Clinical Insights
Mucous gland cysts within the paranasal sinuses are a well-documented clinical entity, most frequently observed in the maxillary sinus. However, their occurrence in the uncinate process—a critical anatomical structure in the nasal cavity—has remained unreported in medical literature until this case. This article presents a detailed analysis of a rare mucous gland cyst localized within the uncinate process, emphasizing its clinical presentation, diagnostic challenges, surgical management, and histopathological findings. The report underscores the importance of recognizing this rare pathology to guide appropriate treatment and avoid misdiagnosis.
Clinical Presentation and Diagnostic Evaluation
A 46-year-old male presented with a five-month history of progressive right-sided nasal obstruction. The onset of symptoms followed an episode of upper respiratory tract infection, during which he developed complete nasal blockage unresponsive to decongestants. Accompanying symptoms included intermittent right-sided headaches, though rhinorrhea was notably absent. Initial nasal endoscopy revealed a light reddish, firm mass obstructing the right nasal cavity, extending to the limen nasi. The mass failed to shrink after topical decongestant application, preventing further endoscopic visualization of deeper nasal structures.
Preoperative sinus computed tomography (CT) imaging demonstrated a homogeneous soft tissue density occupying the anterior right nasal cavity (Figure 1A). Notably, the lesion exhibited no evidence of bony erosion or invasion, complicating its differentiation from benign neoplasms or polyps. Differential diagnoses included nasal polyps, antrochoanal polyps, or benign tumors. The absence of comorbidities such as hypertension, diabetes, or coronary artery disease simplified preoperative risk stratification.
Surgical Intervention and Intraoperative Findings
Given the unresolved obstruction and diagnostic uncertainty, the patient underwent endoscopic exploration under general anesthesia. Intraoperative examination revealed a cystic mass adherent to the lateral nasal wall. During manipulation with cutting forceps, the lesion ruptured spontaneously, releasing 5–6 mL of thick, milky-white fluid (Figure 1C). Subsequent collapse of the cyst facilitated identification of its pedicle, which originated from the superior aspect of the right uncinate process (Figure 1B). Complete excision of the cyst and its pedicle was achieved using elevators and monopolar electrocautery to ablate residual tissue at the uncinate process stump (Figure 1D). Gelatin sponge packing was applied to the surgical site, and the patient was discharged five days postoperatively without complications.
Histopathological Confirmation
Gross examination of the resected specimen revealed a grayish-white cyst measuring 3.0 × 2.0 × 1.8 cm, with a rough internal lining and a wall thickness of 0.1–0.2 cm (Figure 1C). Microscopic analysis confirmed the diagnosis of a mucous gland cyst, characterized by pseudostratified ciliated columnar epithelial lining and submucosal glandular dilatation filled with eosinophilic secretions (Figure 1E). The cyst wall exhibited stromal hyperemia, edema, and mixed inflammatory infiltrates (lymphocytes, plasma cells, neutrophils, and eosinophils), consistent with chronic inflammation. No evidence of malignant transformation or polypoid degeneration was identified.
Pathogenesis and Differential Considerations
The etiology of mucous gland cysts in the uncinate process aligns with proposed mechanisms for sinonasal mucosal cysts. Obstruction of seromucinous gland ducts—secondary to chronic inflammation, allergic rhinitis, or recurrent infections—leads to mucus accumulation and gradual cystic expansion. The uncinate process, with its narrow anatomical confines and dense glandular network, may be predisposed to such obstructive events, though this hypothesis requires further investigation.
This case highlights the diagnostic ambiguity inherent to cystic lesions of the uncinate process. Unlike maxillary sinus cysts, which often present with facial pressure or postnasal drip, uncinate process cysts may mimic neoplasms due to their anterior location and solid appearance on imaging. The absence of bony erosion on CT, combined with a homogeneous density, initially favored benign tumors over cystic lesions. Enhanced CT or magnetic resonance imaging (MRI) could improve preoperative characterization by differentiating fluid-filled cysts from solid masses. The intraoperative discovery of milky fluid remains pathognomonic for mucous gland cysts and should prompt thorough exploration of the uncinate process for residual glandular tissue.
Surgical Management and Technical Nuances
Endoscopic resection is the cornerstone of treatment for uncinate process mucous gland cysts. Key principles include complete removal of the cyst lining to prevent recurrence and meticulous preservation of adjacent mucosa to minimize postoperative synechiae. In this case, intraoperative rupture complicated pedicle identification but inadvertently facilitated targeted dissection. Electrocautery of the uncinate stump ensured eradication of residual glandular epithelium while maintaining sinus ventilation pathways.
Postoperative follow-up at 12 months confirmed complete mucosal healing without recurrence, underscoring the efficacy of this approach. Nevertheless, surgeons must remain vigilant for intraoperative cyst rupture, which may obscure anatomical landmarks and necessitate careful suctioning to maintain visualization.
Clinical Implications and Lessons Learned
This report provides the first documented evidence of a mucous gland cyst arising within the uncinate process, expanding the differential diagnosis for anterior nasal masses. Clinicians should consider this entity in patients with progressive unilateral nasal obstruction unresponsive to medical therapy, particularly when imaging reveals homogeneous anterior nasal lesions without bony destruction.
The case also highlights limitations in preoperative imaging. While CT offers excellent bony detail, its inability to distinguish cystic from solid lesions in this region underscores the value of MRI for T2-weighted hyperintensity—a hallmark of fluid-filled cysts. Intraoperative frozen section analysis may further aid in real-time diagnosis, though histopathological examination remains definitive.
Conclusion
Mucous gland cysts of the uncinate process represent a rare but clinically significant cause of nasal obstruction. Their atypical presentation and imaging features necessitate a high index of suspicion, particularly when conventional diagnoses such as polyps or tumors are inconclusive. Endoscopic excision with histopathological confirmation remains the gold standard for management, ensuring both symptomatic relief and definitive diagnosis. This case underscores the importance of integrating clinical, radiological, and intraoperative findings to optimize outcomes in sinonasal pathology.
doi.org/10.1097/CM9.0000000000000104
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