Nasolabial cyst (Klestadt's cyst) is a rare, non-odontogenic, developmental cystic lesion located beneath the nasolabial sulcus, lateral to the nasal floor. It originates from embryological remnants of the nasolacrimal duct (remnants of the fetal nasolacrimal groove between the inferior nasal meatus and upper lip). Its prevalence is approximately 0.7% and it is 4:1 more common in females. It presents as a slowly growing, painless, smooth-bordered subcutaneous mass; as it enlarges, it creates nasal floor elevation, fullness of the nasolabial sulcus, and nasal vestibule obstruction. On CT and MRI, it appears as a well-defined cystic lesion located extraosseously, anteroinferior to the piriform aperture, anterior to the premaxilla. Treatment is surgical excision (sublabial approach) or marsupialization. When infected, it may present as an abscess.
Age Range
30-60
Peak Age
45
Gender
Equal
Prevalence
Rare
Nasolabial cyst originates from epithelial remnants that occur during formation of the nasolacrimal duct during embryological development. During fetal facial development, the lateral nasal process, medial nasal process, and maxillary process merge; along this fusion line, the nasolacrimal groove (nasolacrimal duct precursor) forms. The nasolacrimal groove normally canalizes to become the nasolacrimal duct; however, epithelial remnants remaining in this process can undergo cystic degeneration to form a nasolabial cyst. The cyst wall is lined by pseudostratified columnar or squamous epithelium — this epithelial type resembles nasolacrimal duct epithelium and confirms its embryological origin. The cyst grows slowly and does not erode surrounding bony structures (extraosseous lesion) but may cause shallow remodeling on the anterior surface of the premaxilla and piriform aperture margin through pressure effect. On imaging, well-defined cystic lesion, extraosseous location, and absence of bone destruction reflect this benign developmental pathology.
Well-defined, fluid-density cystic lesion with extraosseous location on the anterior premaxilla surface, anteroinferior to the piriform aperture on CT — characteristic location and morphology of a lesion elevating the nasal floor and filling the nasolabial sulcus without bone destruction establishes the diagnosis of nasolabial cyst.
On CT, nasolabial cyst appears as a well-defined, homogeneous fluid-density (10-30 HU) cystic lesion with extraosseous location, anteroinferior to the piriform aperture, on the anterior surface of the premaxilla. The cyst wall is thin and smooth; it may not be discernible on non-contrast CT. Bone window settings confirm absence of bone destruction — pressure remodeling (shallow concavity) on the anterior premaxilla surface may accompany. The cyst elevates the nasal floor mucosa, elevating the nasal vestibule floor. Large cysts fill the nasolabial sulcus causing facial asymmetry. On axial CT, the cyst is located between the premaxilla and upper lip soft tissues. On coronal CT, the relationship between the piriform aperture and cyst and compressive effect on the nasal vestibule are evaluated. Infected cysts show wall thickening and surrounding soft tissue inflammatory changes.
Report Sentence
A well-defined, fluid-density cystic lesion measuring approximately X×Y mm with extraosseous location is observed anteroinferior to the left/right piriform aperture on the anterior premaxilla surface, compatible with nasolabial cyst.
On MRI, nasolabial cyst shows homogeneous hyperintense signal on T2-weighted sequences — reflecting free fluid content. The cyst wall appears as a thin T2 hypointense line. Cyst borders are sharp and smooth; there is no lobulation or irregularity. In infected cyst, the cyst wall thickens and T2 hyperintense inflammatory edema develops in surrounding soft tissues. Hemorrhagic cyst content may show variable T2 signal — T2 hypointense in acute hemorrhage (deoxyhemoglobin), T2 hyperintense in subacute period (extracellular methemoglobin). On STIR, the cyst appears markedly hyperintense and surrounding soft tissue inflammation is evaluated. MRI superiority over CT lies in characterization of cyst content and detailed evaluation of surrounding soft tissue relationships (upper lip muscles, nasal mucosa, nasolacrimal duct).
Report Sentence
A well-defined cystic lesion showing homogeneous hyperintense signal on T2-weighted sequences is observed in the nasolabial region, compatible with nasolabial cyst.
On T1-weighted MRI, nasolabial cyst shows variable signal depending on the nature of the content. Cyst containing simple serous fluid is T1 hypointense (long T1 — similar to water). Proteinaceous or mucous content increases T1 signal — intermediate-to-high signal intensity. Hemorrhagic cyst appears T1 hyperintense (methemoglobin effect). On post-contrast T1 fat-suppressed sequences, the cyst wall may show thin smooth enhancement; cyst content does not enhance. Infected cyst shows thickened and intensely enhancing wall with surrounding inflammatory enhancement. T1 sequence is complementary in characterizing cyst content and together with T2 helps determine the fluid/protein/hemorrhagic nature of the content.
Report Sentence
Nasolabial cyst shows hypointense/hyperintense signal on T1-weighted sequences with thin wall enhancement on post-contrast sequences.
Ultrasonography is an effective screening modality for nasolabial cyst evaluation due to its superficial location. With high-frequency linear probe (7.5-15 MHz), a well-defined, anechoic or hypoechoic cystic lesion with posterior acoustic enhancement is observed in the nasolabial sulcus. The cyst wall appears as a thin smooth echogenic line. Presence of internal echoes suggests proteinaceous content, infection, or hemorrhage. Color Doppler may show minimal vascularity in the cyst wall; no vascularity within the cyst (avascular — distinguishing from solid masses). Cyst size, location, and surrounding tissue relationships are evaluated in real-time. Ultrasound-guided aspiration can be performed for both diagnostic (cytology) and therapeutic purposes but recurrence rate is high. Fine-needle aspiration (FNA) with cytological examination of cyst fluid supports the diagnosis.
Report Sentence
A well-defined, anechoic/hypoechoic, avascular cystic lesion with posterior acoustic enhancement is observed on ultrasonography in the left/right nasolabial sulcus, compatible with nasolabial cyst.
Infected nasolabial cyst appears on contrast-enhanced CT as a hypodense collection surrounded by thickened, intensely enhancing wall. Unlike the thin, indiscernible wall of normal nasolabial cyst, in infection the cyst wall shows significant thickening (2-4mm) and intense enhancement. Intracystic density may increase (20-40 HU — purulent material). Inflammatory fat stranding (cellulitis) in surrounding soft tissues (upper lip, nasal floor, cheek) accompanies. Skin thickening and edema may be visible. In rare cases, cyst rupture with surrounding abscess formation may develop. Infected nasolabial cyst presents acutely clinically (pain, redness, swelling) and unlike simple cystic lesion may require emergent treatment. Dental pathology should be excluded — may be confused with periapical abscess.
Report Sentence
A hypodense collection surrounded by thickened and intensely enhancing wall is observed in the nasolabial region, compatible with infected nasolabial cyst; inflammatory changes are present in surrounding soft tissues.
Criteria
Slowly growing, painless cystic lesion. No signs of infection. May be incidentally detected. Thin cyst wall, homogeneous fluid content.
Distinct Features
Homogeneous fluid density on CT. T2 hyperintense, T1 hypointense on MRI. No enhancement. Elective surgical excision can be planned.
Criteria
Cyst infection has developed — pain, redness, swelling. Cyst wall thickened. Surrounding cellulitis findings. Acute presentation.
Distinct Features
Thickened enhancing wall on contrast-enhanced CT. Increased cyst density. Surrounding fat stranding. Surgical excision planned after antibiotherapy.
Criteria
Cystic lesion in both nasolabial sulci. Prevalence is approximately 10% of all cases. May be bilaterally symmetric or asymmetric.
Distinct Features
Symmetric/asymmetric cystic lesions anterior to bilateral piriform apertures on CT. Bilateral nasal floor elevation. Requires bilateral surgical excision.
Distinguishing Feature
Odontogenic cysts (radicular/dentigerous cyst) show intraosseous location within alveolar bone and are related to tooth roots. Nasolabial cyst is extraosseous, located outside bone, and no dental pathology accompanies. Location (intraosseous vs extraosseous) and dental relationship are definitive distinguishing factors.
Distinguishing Feature
Retention cyst arises from sinus mucosa within the sinus lumen and is a dome-shaped intraluminal mass. Nasolabial cyst is extraosseous, located in the nasolabial sulcus outside the sinus. Location is completely different — retention cyst is intrasinusal, nasolabial cyst is extrasinusal and extraosseous.
Distinguishing Feature
Mucocele is a cystic lesion that expansively fills the sinus lumen and causes remodeling/thinning of sinus walls. Nasolabial cyst is extraosseous, located outside the sinus, and does not affect sinus walls. Mucocele is intrasinusal and usually larger; nasolabial cyst is a small 1-3 cm extraosseous lesion.
Urgency
routineManagement
surgicalBiopsy
Not NeededFollow-up
Post-excision follow-up at 3-6 months for recurrence assessment. Recurrence rate is low (<10%) with complete excision.Nasolabial cyst is a benign developmental lesion with no risk of malignant transformation. Small asymptomatic cysts may be observed. For symptomatic cysts (nasal obstruction, facial asymmetry, infection), treatment is surgical excision. Sublabial approach (gingivobuccal sulcus incision) is the standard surgery — the cyst is totally excised. Marsupialization may be applied as an alternative but recurrence risk is higher. In infected cyst, antibiotic therapy is first applied and elective excision is planned after infection is controlled. Needle aspiration may be diagnostic but therapeutic effect is temporary — the cyst almost always recurs. Preoperative CT/MRI supports surgical planning by revealing the cyst size, location, and relationship with surrounding anatomic structures.
Nasolabial cyst is a benign lesion. Treatment is surgical excision or marsupialization via sublabial approach. Recurrence rate is very low after surgical excision. May become infected — in which case heat, swelling, and fullness of the cyst increase.