Congenital Type III Lip Sinus with Palatine Bone Cleft

ABSTRACT

Congenital lip sinuses are rare developmental anomalies that usually occur in isolation, except for lower lip sinuses, which may be associated with cleft palate. We present a rare case of a congenital upper lip sinus associated with palatine bone cleft, unilateral choanal atresia, and epibulbar dermoid in a neonate.

INTRODUCTION

Congenital lip sinuses are rare anomalies with an estimated incidence between 0.001% and 0.00001% for upper and lower lip sinuses, respectively.[1,2] They have been classified into three types based on location and associated anomalies.[3] Midline sinuses of the upper lip without associated anomalies are referred as type I, whereas those with associated anomalies are called as type II. Lateral lip sinuses of the upper lip with or without anomalies are classified as type III. Lower lip sinuses are reported more frequently compared to upper lip pits and often associated with cleft lip or palate as a part of Van der Woude syndrome.[4] Existing literature on 14 cases of lateral lip sinuses mentioned these tracts to end in the mucosa without intraoral communication.[1] Here, we report a case of left-sided lateral lip sinus in a neonate with ipsilateral palatine bone cleft, contralateral bony choanal atresia, and epibulbar dermoid that was also evaluated by whole-genome sequencing (WES).

CASE REPORT

An outborn term female neonate weighing 2750 g born by spontaneous vaginal delivery to a second gravida mother was admitted on day 3 of life with respiratory distress. On examination, the neonate was alert with mild respiratory distress (Downes score 3) with occasional stridor. Careful assessment of facial features revealed a small pit on the upper lip, left to the philtrum below the nostril. On probing the small opening with a 26-G cannula without stylet, the pit was found to be blind not opening into the oral or nasal cavity, suggestive of lip sinus [Figure 1a and b]. On nasogastric tube insertion, feeding tube failed to pass the right nostril suggestive of unilateral right-sided choanal atresia. There was a light yellow swelling on the right bulbar conjunctiva suggestive of epibulbar dermoid [Figure 1a]. A computed tomographic scan revealed right partial bony choanal atresia [Figure 1c] with a cleft in the palatine bone [Figure 1d]. Clinically, the overlying palatal mucosa was intact, with no evidence of a classical cleft palate. Echocardiography and ultrasound of the abdomen were normal. Bilateral hearing and thyroid screen were also normal. There was no history of consanguinity or dysmorphic features in the parents or elder sibling. In view of these congenital anomalies, the possibility of Goldenhar syndrome was kept, and WES was sent. In addition, plastic surgery, otorhinolaryngology, and ophthalmology consultations were taken for the surgical correction of lip sinus and concealed cleft palate, choanal atresia, and epibulbar dermoid at the appropriate age in follow-up. The baby was stable throughout the hospital stay. Continuous positive airway pressure support started for respiratory distress could be stopped after 24 h of hospital stay. Initially, feeding was started through an orogastric tube with expressed breast milk, and as the respiratory distress resolved, she started accepting direct breast feeds from day 5 of life. The baby was discharged on day 14 of life with advice for multidisciplinary follow-up.

Figure 1.

(a) Clinical photograph showing lip sinus (thick short arrow) and epibulbar dermoid (thin arrow), (b) Lip sinus probed with cannula without stylet, (c) Three-dimensional (3D) volume rendered computed tomography (CT) image showing right-sided bony choanal atresia, (d) 3D volume rendered CT image showing palatine bone cleft. 3D: Three-dimensional, CT: Computed tomography

Genetic report revealed a heterozygous missense variant in exon 40 of the KMT2D gene (chr12:g.49033121G>T; Depth: 85x) resulting in the amino acid substitution of lysine for glutamine at codon 3862 (p.Gln3862 Lys; ENST00000301067.12). The identified variant was classified as a variant of uncertain significance. To confirm its significance, parental genetic sequencing was planned. However, parents declined due to financial constraints and reported no plans for future pregnancy.

DISCUSSION

Congenital lateral lip sinuses are rare malformations predominantly reported to occur as an isolated anomaly. The hypotheses explaining the occurrence of these sinuses include either origin from embryological remnants[3] or failure of involution of epithelial remnants following the fusion of maxillary and medial nasal processes.[3] The lip sinus in our patient is morphologically distinct from the classical lip pits of Van der Woude syndrome, which are typically bilateral paramedian depressions of the lower lip vermilion. In contrast, our patient demonstrated a unilateral lateral upper lip sinus near the nasolabial junction with a patent tract, suggesting a different embryologic origin likely related to abnormal fusion between the maxillary and medial nasal processes.

Previous cases of lateral lip sinus more often affected females on the left side of the vermilion border. The present case also occurred in a female neonate, and the site of sinus was left to the philtrum. These cases manifested as a pit with intermittent whitish discharge or swelling and were treated successfully with surgery.[1,2,3,4] In cases of congenital lip sinuses, the treatment of choice remains complete excision of the sinus track with a clear margin for correction of cosmetic deformity and recurrent infections or discharge. As our neonate had an asymptomatic lip sinus, elective surgical excision was planned in follow-up.[1] Additional anomalies noted in the index were concealed cleft of the primary palate on the left side and unilateral right-sided bony choanal atresia. The palatine cleft in our case was discernible only by computed tomography scan without any clinically visible mucosal cleft, alveolar notch, feeding difficulty, or oronasal regurgitation. Hence, no immediate surgical intervention was decided in consultation with plastic surgeons. Instead, the neonate was planned to be followed up in the plastic surgery and dentistry departments for dentoalveolar growth, speech development, and future need for corrective surgery.[5] Moreover, the respiratory distress related to choanal atresia was mild and settled with continuous positive airway support over the next 24 h of hospitalization. Otorhinologists planned for elective surgical repair based on growth and persistence of symptoms.[6]

The presence of a small limbal epibulbar dermoid in the inferonasal part of the right eye did not warrant immediate management as it was not encroaching on the pupillary area. Pediatric ophthalmology consultation was sought, and she was planned for monitoring of the vision and cycloplegic refraction later in follow-up.[7]

Prior cases of lip sinuses were not syndromic, and no genetic work-up was done. In the present case, the neonate had a lip sinus that led into palatine cleft, unilateral choanal atresia, and epibulbar dermoid with WES showing a variant of KMT2D gene. Variants in KMT2D have been associated with phenotypes including branchial arch abnormalities, choanal atresia, athelia, hearing loss, and hypothyroidism (BCAHH syndrome), as well as Kabuki syndrome type 1.[8] In the index case, the typical facies of Kabuki syndrome was absent. These clinical findings either represent partial BCAHH syndrome or help us to expand the phenotypic spectrum of KMT2D gene variants beyond those seen in Kabuki syndrome.

Lateral upper lip sinuses may also be associated with a palatine cleft that may remain clinically inconspicuous along with other craniofacial anomalies as in the present case. Genetic studies in the current era are important to unravel gene variants associated with these anomalies. Management of lip sinuses and associated anomalies such as unilateral choanal atresia, concealed cleft palate, and epibulbar dermoids may not need immediate surgery in the neonatal period, especially if the neonate remains clinically asymptomatic. However, the conditions need long-term surveillance for dentoalveolar growth, speech, and development of induced astigmatisms.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the legal guardian has given his consent for images and other clinical information to be reported in the journal. The guardian understands that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.