An eruption cyst (EC) is a benign developmental odontogenic cyst that accompanies an erupting primary or permanent tooth, appearing shortly before the tooth emerges in the oral cavity. According to World Health Organisation classification of Odontogenic tumours, the EC is a separate entity. It is a type of Dentigerous cyst located in the soft tissues without any bone involvement [1]. In some cases, this unusual lesion is associated with natal teeth. Eruption cysts may develop from remnants of the enamel organ epithelium after enamel formation is complete, or from remnants of the dental lamina that surrounds erupting teeth; however, the exact cause remains unknown [2]. Also, they can be very disconcerting to the parents making it crucial for clinicians to accurately diagnose the lesion to avoid unnecessary surgical interventions.

A 2-day-old male infant, born full term through spontaneous vaginal delivery with insignificant antenatal period was noted to have a swelling on the lower gum where the primary central incisor was erupting. The lesion, identified during a routine neonatal examination by the paediatrician, was asymptomatic on initial assessment. It presented as a soft tissue mass in the anterior region of both the upper and lower gingiva, measuring 4 mm x 2 mm x 2 mm, and was uninflamed and fluctuant. The rest of the oral cavity appeared normal, and all other parameters were within normal limits. There were no developmental anomalies or syndromes in the family history.

The infant experienced no difficulties with feeding. However, the mother and other family members were highly concerned. After counseling, they readily agreed to periodic monitoring, initially every 7 days for 1 month and later once a month for six months.

Figure 1: Gingival bulge in the anterior mandible and maxilla, equivalent to the presence of central incisors.

On Day 1, the cyst appeared transparent. The parents were reassured about the benign nature of the lesion and advised on maintaining proper oral hygiene. A radiograph taken revealed the presence of primary teeth in the arch inside the cyst. A provisional diagnosis of an eruption cyst was made based on the clinical and radiographic findings.

Figure 2: Radiographic appearance of the reported area in mandible and maxilla.

One week post birth, the cyst showed no significant change in size or colour and the infant continued to feed normally without any discomfort.

Figure 3: Gingival bulge in the anterior mandible and maxilla 1 week post birth.

During the third visit, two weeks later, the cyst began to spontaneously decrease in size, and its transparency became less pronounced, indicating ongoing resolution.

Figure 4: 2 weeks post birth, showing a spontaneous reduction in lesion size in the anterior mandible and maxilla.

By one month post-birth, the cyst had further decreased in size, revealing a more normal color with diminished transparency.

Figure 5: One-month follow-up, showing a significant reduction in lesion size in the anterior mandible and maxilla.

By the fourth month, the lesion had completely disappeared, and the mandibular deciduous central incisors erupted without any complications.

Figure 6: Four months follow-up, showing normal eruption of the mandibular deciduous central incisors.

Follow-up radiographs indicated normal root development of the central incisors. The patient remains under observation, showing a normal eruption sequence and complete regression of the initial lesion.

Figure 7: Four months follow-up, radiographic appearance of the reported area in mandible and maxilla.

Eruption cysts are rare in newborns but are more commonly observed between the ages of 6-9 years, coinciding with the eruption of permanent incisors and molars [3]. Eruption cysts with natal teeth may be associated with certain syndromes and hence it is essential for any newborn to undergo a thorough intraoral examination. Clinically, the eruption cyst appears as a circumscribed, floating, often translucent volumetric bulge on the mucosa at the site of tooth eruption. Discomfort is rare; however, the presence of this lesion can hinder or even harm the appearance of teeth in the oral cavity [4].

Our case presented a typical eruption cyst that gradually decreased in size over a period of four months. Several radiographs were taken to confirm the presence of normal deciduous central incisors and to rule out any bony involvement. Most eruption cysts do not require treatment and resolve spontaneously [4]. The repeated compression from feeding may help reduce lesion size and cause rupture [5].

The current treatment options for eruption cysts include no procedure and monitoring, marsupialisation, or surgical extraction of the involved tooth [2,6,7]. When these cysts prevent the eruption of a deciduous tooth, marsupialization may be considered. Extraction is indicated when the teeth present mobility or interfere with lactation [8]. In this case of congenital eruption cyst, the treatment of choice was monitoring of the lesion, without any surgical intervention or tooth extraction.

Our report highlights the self-limiting nature of the lesion and stresses the importance of clinical observation and parental reassurance. Early identification and proper management by healthcare providers can help reduce parental anxiety and ensure optimal oral health monitoring during early infancy.

Eruption cysts are benign lesions that can be managed conservatively. It is important to reassure and counsel parents about the benign and self-resolving nature of these cysts. By documenting the clinical course and conducting follow-up visits, healthcare providers can improve their understanding and offer informed care for infants experiencing similar oral conditions early in life. Periodic oral assessments and radiographic follow-up visits are essential.

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