Lingual hamartomatous lesions can be divided into 4 types depending on the predominant tissue. They are (1) neurovascular, (2) predominantly fatty, (3) smooth muscle, and (4) fatty and predominantly smooth muscle hamartomas which are also called leiomyomatous hamartomas [1]. As per the histopathological description, the present case can be classified as a smooth muscle hamartoma. The majority of lingual hamartomatous lesions have been observed in children and adolescents [4]. In a review by Kreiger et al. [1], the dorsal anterior tongue was the most commonly affected site. In a literature review by Liu et al. [3], most of these types of lesions were located at the base of the tongue in the midline, while the second most affected area after that was the back of the tongue. Hamartomas of the tongue have been described in the medical literature in patients with tuberous sclerosis and orofacial-digital syndrome [3, 4]. Lingual hamartomas can be pedunculated, polypoid, or sessile.
Patients with lingual hamartomas are usually asymptomatic. Symptomatic children may have feeding difficulties and even failure to thrive [3]. A lingual hamartoma located posteriorly should be thoroughly investigated particularly when the lesion is adjacent to the foramen cecum. A lingual thyroid can be located in the same area, and surgical excision of the mass without adequate work up may render the child hypothyroid as it may be the patient’s only functioning thyroid tissue [3]. Clinical examination and ultrasound of the neck can confirm whether the cervical thyroid is present. Lingual thyroid tissue can however coexist with a normal carotid thyroid. In the event of any doubt, a thyroid uptake scans can be done for confirmation [3]. In our case, the anterior tongue lesion ruled out the possibility of a lingual thyroid, and hence, no further imaging study was carried out.
The differential diagnosis of congenital lesions of the tongue include lingual thyroid, vascular and lymphatic lesions (capillary hemangioma, lymphangioma, pyogenic granuloma), traumatic lesions and benign and malignant neoplasms [1, 3]. Because lingual hamartomas can clinically resemble other lesions, histopathologic evaluation is required for a definitive diagnosis [3]. In some cases, CT and MRI are used, although their usefulness is limited for two reasons. The first is that since the oropharynx is often apparent on inspection, CT and MRI findings are less useful in characterizing lingual hamartomas. The second reason is that radiation exposure, especially in children, carries a high risk [3, 5].
Complete excision of the tumor is the treatment of choice with the inclusion of margin when there is suspicion of malignancy in the differential diagnoses [3]. Surgical approach is usually transoral using either conventional methods or a laser if the size of the tumor does not exceed 3 cm [6, 7]. In the case of a large tumor involving the tongue base and the vallecula, a suprahyoid pharyngotomy approach is recommended by some authors because it allows for better vascular control in richly vascular lesions [4]. The prognosis is favorable with no recurrence of cases after complete excision surgery [8,9,10].
