Nasolabial cyst: a retrospective analysis of 18 cases. (Original Article).

Abstract

Nasolabial cysts are rare but easily identifiable when they do occur. They are thought to arise from the remnants of the nasolacrimal ducts, but most of the available information on these cysts is limited to isolated case reports. The purpose of our study was to examine the clinical and pathologic features of nasolabial cysts in order to provide a basis for their correct diagnosis and treatment. Eighteen patients with nasolabial cysts were treated at Korea University's Guro Hospital between Jan. 1, 1988, and Dec. 31, 1999. We retrospectively analyzed the clinical appearance, pathologic findings, and treatment results in each case. All patients underwent surgery via the sublabial approach. The lining epithelia were identified as either pseudostratified, stratified squamous, or simple cuboidal. A cyst recurred in only one case, and there were no surgical complications on follow-up. The results of our study provide a basis for sound diagnosis and treatment.

Introduction

A nasolabial cyst is the result of an ectodermal developmental swelling that manifests as a mass on the lateral half of the floor of the nasal vestibule at the base of the nasal ala. (1, 2) It was first described in 1882. (1) It is a nonodontogenic cyst, and it rarely invades bone. Its pathogenesis is unknown, but many researchers believe that it might arise from remnants of the nasolacrimal ducts. (3)

In this article, we describe our retrospective analysis of the clinical appearance, pathologic findings, and treatment results in 18 cases of nasolabial cyst in order to assist the otolaryngologist in the diagnosis and treatment of this rare entity.

Patients and methods

Eighteen patients were diagnosed with nasolabial cyst during the 12-year span between Jan. 1, 1988, and Dec. 31, 1999, at Korea University's Guro Hospital in Seoul. The diagnosis in each case had been established by correlating the clinical, histologic, and in some cases radiologic findings. Information on the clinical picture, duration of symptoms, size and location of the cyst, and treatment was obtained from a retrospective review of each patient's medical record. The type of lining epithelium and the presence or absence of goblet cells were observed on the archived pathologic specimens.

Results

Age and sex. The 18 patients composed 13 women, four men, and one boy, aged 17 to 67 years (mean: 42.8) (table 1). The disease was most common during the fifth decade of life (n= 7 [38.9%]).

Size and sites. The size of the cysts ranged from 1 x 1 to 3 x 5 cm. The cyst was located on the left side in 10 patients (55.6%) and on the right in eight (44.4%).

Signs and symptoms. The most common complaint was swelling in the nasolabial region in 10 patients (55.6%), followed by nasal obstruction in five (27.8%) and pain in three (16.7%).

Duration of symptoms. The interval between the onset of symptoms and the first visit to an otolaryngology clinic ranged from 1 month to 6 years (table 2). Ten patients (55.6%) were seen within 6 months.

Radiologic findings. Computed tomography (CT) was performed on 11 patients, and it generally showed a well-demarcated, low-density cystic lesion lateral to the pyriform aperture (figure 1). Invasion of the adjacent bone was not observed in any of these patients, and no abnormalities of the alveolar bone were detected.

Histopathologic findings. Pseudostratified columnar epithelium was identified in 11 patients (61.1%), stratified squamous epithelium in five (27.8%) (figure 2), and simple cuboidal epithelium in two (11.1%). Goblet cells were present in 10 patients (55.6%).

Treatment and prognosis. Surgical excision via the sublabial approach was performed on all patients. Re-excision was necessary in one patient when the cyst recurred after 8 months. All patients were monitored via outpatient clinic visits and telephone calls. The duration of follow-up ranged from 6 months to 11 years. No postoperative complications or other recurrences were reported.

Discussion

Etiology. Nasolabial cysts are nonodontogenic masses that arise in maxillofacial soft tissues. (4) There are numerous theories regarding their origin. In 1913, Klestadt suggested that they arise from trapped epithelium at the point where the maxillary, medial nasal, and lateral nasal processes fuse. (5) From this concept came the term fissural cyst. However, a lack of evidence to support the idea of embryonic epithelial entrapment in this location prompted many researchers to discard this hypothesis. (2)

The fact that these lesions are located subjacent to the wing of the nose suggests that they might arise from remnants of the nasolacrimal ducts. (1,2) Bruggemann (3) suggested in 1920 that nasolabial cysts originate in the lower part of the nasolacrimal ducts, a concept that was endorsed by Roed-Petersen (6) in 1969. Trauma has also been mentioned as an initiating factor in the proliferation of the epithelial components. (1) However, the hypothesis that has garnered the most acceptance is that nasolabial cysts develop from remnants of the embryonic nasolacrimal ducts. (4,7) This theory is supported by the fact that the nasolacrimal ducts are lined with pseudostratified columnar epithelium, which is the type of epithelium found in the nasolabial cyst cavity. (2)

Incidence. Nasolabial cysts are rare. In his series of 1,345 jaw cysts, Shear found that only nine were nasolabial cysts (0.7%). (8) Likewise, Allard found only three cases in 65,000 patients (<0.01%). (4)

Clinical characteristics. Although there is a wide age distribution among affected patients, most are in the fourth or fifth decade of life. Moreover, numerous investigators have reported a greater incidence among women than men. Our findings are in line with these earlier reports.

Bilaterality has been reported in about 10% of patients (there was none in our study). (1,9) Unilateral cysts are evenly divided between the two sides of the nose, a finding that is consistent with ours.

Most nasolabial cysts appear as spherical masses embedded beneath the soft tissue of the nasal ala. (1,9) Facial deformity can occur if a cyst enlarges anteriorly or in the pyriform aperture. A mass can also extend inferiorly into the gingivolabial sulcus or laterally into the facial soft tissue and cause a widening of the nasal vestibule, swelling of the upper lip, obliteration of the nasolabial fold, elevation of the nasal floor, and swelling in the nasal and oral cavity. (4) The elevation or medialization of the inferior turbinate can cause nasal obstruction. Pain is uncommon unless the cyst is secondarily infected. Such an infection can be initiated by trauma or by surgical intervention, such as aspiration or incision. In our study, swelling of the nasolabial fold was the most common complaint, followed by nasal obstruction and pain. Some cysts are found during routine dental procedures. Although these cysts do not invade surrounding bone, a few rare cases of resorption of the apices of the teeth have bee n reported. (7)

Diagnosis. The diagnosis of nasolabial cyst is established by correlating the lesion's clinical features and histopathologic findings. Although a cyst can be palpated bimanually (i.e., with one finger on the floor of the nose and one finger in the gingivolabial sulcus), its precise dimensions are better appreciated by CT. The differential diagnosis should include periapical abscess, dentigerous cyst, and nasal furuncle. (9,10)

Routine intraoral periapical radiographs are not necessary in all patients, but they do help differentiate other dentigerous cysts. Radiographs of nasolabial cysts that have persisted for a prolonged period might demonstrate a depression on the labial surface of the maxilla. Analysis of radiographs following injection of a contrast medium into the cyst might aid in differentiating the cyst from osseous structures, but the benefits of this procedure must be carefully weighed against the risk of infection. (2,4)

Histologically, a nasolabial cyst is made up of an epithelium-lined cavity surrounded by a connective tissue wall. (2) Pseudostratified columnar epithelium is the most common type of lining. Cysts lined with stratified squamous epithelium and simple cuboidal epithelium have also been observed. The possible pluripotential character of the embryonic epithelial nests and the transformation of respiratory to squamous epithelium have been proposed to explain the various types of epithelial lining. (2,4) Goblet cells are present in some cases. In Roed-Petersen's study, goblet cells were observed in 60% of patients. (6) This finding is consistent with ours (55.6%). Although infrequent, hemorrhage or chronic inflammation has been observed.

Treatment. Simple surgical excision via the sublabial .approach is sufficient for treatment. (9,10) The incision should be made in the gingivolabial fold over the convexity of the swelling--but not through the mucoperiosteum because it is in the wrong tissue plane. When the cyst extends to the nasal floor, there is a risk of perforation. Large nasal defects should be repaired by suture. Su et al reported satisfactory results with marsupialization under endoscopy. (11) Recurrence and malignancy are very rare. (10)

In conclusion, the 18 cases in this series were clinically similar, and surgical excision yielded satisfactory results. Nasolabial cysts should be considered in the differential diagnosis in patients who have a cystic mass in the nasal vestibular area that is accompanied by swelling, nasal obstruction, and/or pain.

From the Department of Otorhinolaryngology--Head and Neck Surgery, Korea University college of Medicine, Seoul.

Reprint requests: Heung-Man Lee, MD, Department of Otorhinolaryngology--Head and Neck Surgery, Guro Hospital, Korea University College of Medicine, 80 Guro-dong, Guro-gu, Seoul 152703, Korea. Phone: [phone]; fax: [phone]; e-mail: [e-mail]

References

(1.) el-Din K, el-Hamd AA. Nasolabial cyst: A report of eight cases and a review of the literature. J Laryngol Otol 1999;113:747-9.

(2.) Vasconcelos RF, Souza PE, Mesquita RA. Retrospective analysis of 15 cases of nasolabial cyst. Quintessence Int 1999;30:629-32.

(3.) Bruggemann A. Zysten als Folge von Entwicklungsstorungenim Naseneinging. Arch Laryngol Rhinol 1920;33:l01-5.

(4.) Allard RH. Nasolabial cyst. Review of the literature and report of 7 cases. Int J Oral Surg 1982;1l:351-9.

(5.) Klestadt W. Gesichtsspaltenzystew. Ben Klin Wochenschr 1913;50: 1683-5.

(6.) Roed-Petersen BA. Nasolabial cysts. A presentation of five patients with a review of the literature. Br J Oral Surg 1969;7:84-95.

(7.) Wesley RK, Scannell T, Nathan LE. Nasolabial cyst: Presentation of a case with a review of the literature. J Oral Maxillofac Surg 1984;42:188-92.

(8.) Shear M. Cysts of the Oral Regions. 2nd ed. Bristol, U.K.: J. Wright, 1983:108-11.

(9.) Hwang SH, Park BW, Kim MG. A clinical study of nasolabial cyst. Korean Journal of Otolaryngology 1998;41:604-7.

(10.) Lopez-Rios F, Lassaletta-Atienza L, Domingo-Carrasco C, Martinez-Tello FJ. Nasolabial cyst: Report of a ease with extensive apocrine change. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997;84:404-6.

(11.) Su CY, Chien CY, Hwang CF, A new transnasal approach to endoscopic marsupialization of the nasolabial cyst. Laryngoscope 1999;109:1116-8.

Table 1

Distribution of patients according to age and sex (N = 18)

  Age     Male  Female
  (yr)    (n)    (n)

10 to 19   1      0
20 to 29   2      1
30 to 39   1      2
40 to 49   1      6
50 to 59   0      3
60 to 69   0      1

Total      5     13
Table 2

Duration of symptoms (N = 18)

Duration        n (%)

1 to 6 mo     10 (55.6)
6 mo to 1 yr   3 (16.7)
1 to 2 yr      3 (16.7)
2 to 6 yr      2 (11.1)