Introduction

The size of a tongue varies with age, experiencing the most significant growth in the first eight years of life and reaching full size by age 18.¹ Macroglossia refers to a long-term, painless enlargement of the tongue.² This condition, meaning "large tongue," has been recognized for centuries. Formerly, Virchow called it a form of elephantiasis.

In the past century, Butlin and Spencer linked it to lymphatic dilation, muscle hypertrophy, or inflammation.³ The incidence of macroglossia is estimated at 1%.⁴ However, a study on tongue disorders in children found macroglossia to be one of the most common diagnoses, accounting for 24% of cases.⁵

The prevalence of congenital macroglossia is reported to be fewer than 5 per 100,000 births, being twice as common in females as in males and twice as common in African-Americans compared to the European genealogy.⁶ Additionally, macroglossia has a positive family history in 6% of cases.⁷

What is Macroglossia?

Macroglossia is an abnormal enlargement of the tongue. It is clinically diagnosed when the tongue protrudes beyond the teeth during resting posture. This condition can occur in isolation or in association with other conditions or syndromes.⁸

Macroglossia can be classified into two main categories:⁹

• True macroglossia: a genuine enlargement of the tongue
• Relative macroglossia (or pseudomacroglossia): where a normal-sized tongue appears large relative to adjacent anatomical structures

There is also a third classification known as the functional type of macroglossia, which occurs when the tongue does not properly adapt to the oral cavity following a surgical procedure that reduces the volume of the cavity.¹⁰

True or relative macroglossia can be categorized into two main sub-types: congenital and acquired. Congenital macroglossia may result from Down syndrome, idiopathic muscular hypertrophy, Beckwith-Wiedemann syndrome, Crouzon syndrome, Hurler syndrome, Maroteaux-Lamy syndrome, among others.

Acquired macroglossia, on the other hand, can be caused by metabolic disorders such as diabetes mellitus, hypothyroidism, cretinism, and acromegaly. It can also arise from inflammatory conditions like pneumonia, glossitis, tuberculosis, head and neck infections, allergic reactions, trauma, surgical procedures, haemorrhage, radiation, hemangioma, lipoma, and amyloidosis.¹¹

Signs and symptoms of macroglossia include noisy breathing (dyspnea), difficulty swallowing and eating (dysphagia), disrupted speech (dysphonia), drooling, and sores at the corners of the mouth (angular cheilitis). Additional symptoms are indentations on the lateral borders of the tongue caused by pressure from the teeth (crenated tongue or "pie crust tongue"), malocclusion of the teeth, an enlarged mandible, and mouth breathing. The tongue constantly protrudes from the mouth and is vulnerable to drying out, ulceration, infection, or necrosis.¹²

Diagnosis

Clinical diagnosis

Various clinical and cephalometric features can help a clinician recognize the presence or absence of macroglossia. Clinical diagnosis considers signs such as an enlarged or elongated, broad, flat tongue, spacing between front teeth (diastema) or posterior tooth spacing, chronic positioning of the tongue between the teeth at rest, malocclusion, crenations on the tongue (impression marks from contact with the teeth), glossitis (inflammation of the tongue), speech articulation disorders, asymmetry in the upper and lower arches, eating and swallowing difficulties, instability in orthodontic instruments or orthognathic surgical procedures that would normally be stable, respiratory problems like obstructive sleep apnea, and drooling.

A typical clinical examination for macroglossia includes assessing a patient's ability to extend their tongue to reach their chin or the tip of their nose.¹³ However, in edentulous patients, clinical and radiographic diagnosis of macroglossia is challenging because dental or occlusal relations are difficult to determine.¹⁴

In addition to clinical examination, cephalometric radiographic features can aid in diagnosing macroglossia, such as disproportionate mandibular growth with dentoalveolar protrusion.¹⁵ However, McKenna et al. studied the structure and morphology of the tongue and claimed that no diagnostic assessment is more effective than a thorough clinical examination.¹⁶

Symptomatic diagnosis

Thoroughly reviewing the patient's medical history and conducting a detailed physical examination are essential to identify any undiagnosed syndromes. Examination of the tongue should assess changes in colour and consistency, as well as the presence of any masses. Additional laboratory and imaging tests should be performed based on clinical suspicion of a specific condition.

For instance, thyroid function tests, isotopic imaging of the thyroid gland, chromosomal studies, molecular studies for Beckwith-Wiedemann syndrome, metabolic profile analysis, urinary mucopolysaccharide assay, and abdominal ultrasound may be warranted.¹⁷

Functional tests may be performed to detect changes in eating, speech, or airway function. For instance, a polysomnogram may be conducted to assess for sleep apnea and dysphagia tests may be utilized to evaluate the risk of swallowing difficulties.

Additionally, when the aetiology of macroglossia is unknown, a biopsy of the tongue may be performed to rule out conditions such as tumours, amyloidosis or lymphoma.¹⁸ Sleep endoscopy and imaging techniques may also be employed to assess obstructive sleep apnea.¹⁹

Suppose neoplasia is suspected based on the examination. In that case, a diagnosis can often be made by an experienced professional obtaining samples of the tongue lesion via fine needle aspiration in the clinic. For larger lesions, a biopsy in an operating theatre may be required. Computed tomography (CT) and magnetic resonance imaging (MRI) can be useful for delineating soft tissues and determining the extent of tumours and other masses.

Additionally, an electrocardiogram (ECG), echocardiogram, chest X-ray, and arterial blood gas analysis may be necessary for patients presenting with symptoms of chronic airway obstruction to rule out underlying cardiac complications.²⁰

Differential diagnosis

Relative macroglossia is the primary differential diagnosis for true macroglossia. Acute tongue swelling may result from angioedema or a local inflammatory condition causing glossitis.²¹

Treatment

The treatment of macroglossia varies depending on its underlying cause. In some cases, children with macroglossia may naturally "outgrow" the condition as their facial bones develop and their mouths accommodate their tongues.²² When macroglossia is associated with a congenital disorder, treatment typically includes orthodontic intervention and speech therapy to help manage tongue positioning during various functions.

Surgery may be recommended if macroglossia causes breathing difficulties or feeding problems. A common surgical approach performed by maxillofacial surgeons is partial glossectomy, which involves reducing the size of the tongue.

Summary

Macroglossia, characterized by an abnormal enlargement of the tongue, presents a complex diagnostic and treatment challenge. The condition's prevalence and aetiology vary widely, with congenital and acquired factors contributing to its manifestation. Clinical examination remains pivotal in identifying macroglossia, considering features such as tongue size, dental spacing, and associated symptoms like dyspnea and dysphagia.

Diagnostic investigations, including imaging and functional tests, aid in confirming the diagnosis and evaluating underlying causes. Differential diagnosis distinguishes true macroglossia from other conditions causing tongue enlargement. Treatment strategies range from observation to surgical intervention, tailored to address the underlying cause and alleviate symptoms.

Early recognition and appropriate management are crucial for improving patient outcomes and quality of life in individuals affected by macroglossia. Collaboration among medical specialists ensures comprehensive care and optimal treatment outcomes.