Epidermoid cysts of the floor of the mouth are rare benign lesions that may present a diagnostic and therapeutic challenge due to their deep anatomical location and nonspecific clinical presentation [6].

They arise either from congenital ectodermal entrapment during embryologic fusion or, less commonly, from acquired causes such as traumatic or iatrogenic implantation of epithelial cells [2,6].

Clinically, these lesions typically manifest as slow-growing, painless swellings in the midline of the floor of the mouth.

However, depending on their size and location, they may lead to functional symptoms including dysphagia, dysarthria, tongue elevation, and, in severe cases, airway compromise [5,7].

In our case, the patient presented with mild functional discomfort without respiratory distress, which is consistent with early-stage lesions.

The differential diagnosis is broad and includes ranula, thyroglossal duct cyst, lymphangioma, cystic hygroma, and benign or malignant salivary gland tumors [7].

Distinguishing between these entities is crucial, as management strategies differ significantly. For instance, ranulas are typically associated with salivary gland extravasation and may require marsupialization or gland excision, whereas epidermoid cysts require complete surgical enucleation.

Radiological imaging plays a central role in both diagnosis and preoperative planning. CT scans typically reveal well-circumscribed, hypodense, non-enhancing lesions, while MRI offers superior soft tissue resolution and can better delineate the lesion’s relationship with adjacent muscles and neurovascular structures [8]. MRI may also help differentiate epidermoid cysts from dermoid cysts based on internal content characteristics. In our case, CT imaging was sufficient to establish the diagnosis and determine the surgical approach.

The anatomical classification proposed in the literature, based on the relationship of the cyst to the mylohyoid and geniohyoid muscles, is fundamental in guiding surgical management [9,11]. Lesions located above the mylohyoid muscle (sublingual space) are generally approached intraorally, whereas those located below the geniohyoid muscle (submental or submandibular spaces) often require an extraoral cervical approach.

The intraoral approach offers several advantages, including the absence of visible scarring, reduced surgical morbidity, shorter operative time, and faster postoperative recovery [10,12].

For these reasons, it should be preferred whenever anatomically feasible. Nevertheless, this approach requires meticulous surgical technique due to the proximity of critical structures such as Wharton’s ducts, the lingual nerve, and the sublingual glands. Inadequate dissection may result in complications such as ductal injury, sensory deficits, or incomplete excision.

Traditionally, large cysts were considered indications for an extraoral approach due to concerns regarding limited exposure and risk of rupture. However, recent studies have demonstrated that even relatively large cysts can be successfully managed intraorally with careful dissection and adequate surgical expertise [10,12,13]. This trend reflects a shift toward minimally invasive techniques in head and neck surgery.

Complete surgical excision remains the gold standard treatment, as partial removal or rupture of the cyst wall may increase the risk of recurrence. Fortunately, recurrence rates are low when complete enucleation is achieved [14]. Malignant transformation of epidermoid cysts is exceedingly rare but has been reported in the literature, emphasizing the importance of histopathological examination [14].

In our case, the lesion was located between the mylohyoid muscle and the geniohyoid muscle, allowing successful management via an intraoral approach with excellent functional and aesthetic outcomes. No postoperative complications or recurrence were observed, supporting the safety and efficacy of this technique.