Macroglossia (2024)

Abstract

Macroglossia is defined as an enlarged tongue and it is usually clinically diagnosed. Pseudomacryglossia concerns a tongue that is of normal size but gives a false impression of being too large in relation to adjacent anatomical structures. The causes of macroglossia are numerous and this is why various classifications have been proposed for this condition. The consequences of macroglossia usually include a possible malfunction of the stomatognathic system, breathing and speech problems, increased mandible size, tooth spacing, diastema and other orthodontic abnormalities. The treatment of macroglossia depends on its aetiology and generally includes correcting the systemic disease underlying the increase in lingual mass, surgical treatment, radiotherapy and treatment of orthodontic abnormalities that might have been caused by the condition.

Key words: Macroglossia, abnormalities, malfunction

INTRODUCTION

Boucher defines macroglossia as an enlarged tongue due to muscular hypertrophy, tumour or endocrine disorder1., 2.. Other authors define it as a clinical condition where the resting tongue protrudes from the alveolar crest3., 4.. Macroglossia is an anatomical abnormality and it is usually clinically diagnosed and confirmed with cephalometric analysis. Quite often macroglossia coexists with anterior open bite and tooth spacing.

Pseudomacroglossia is a condition in which the tongue may be of normal size but appears to be large in relation to adjacent anatomical structures4., 5.. This happens in cases when the tongue interferes with the teeth, when there is hypertrophy of the tonsils, which forces the tongue forward, when the palatal vault is low and leads to reduced oral cavity volume, when there is deficiency of mandibular or maxillary dental arches which leads to reduced oral cavity dimensions or when the presence of tumours force the tongue forwards6., 7., 8.. It is important that pseudomacroglossia should be differentially diagnosed from true macroglossia, because the treatment of the two conditions might be differ4.

Macroglossia is considered to be rare among children9. However, according to a study on tongue disorders in a child population, macroglossia was one of the most common diagnoses (24%)10. It is difficult to determine the accurate incidence of macroglossia because of its multiple causes. Various syndrome phenotypes include macroglossia, such as Down syndrome11., 12. (incidence: 1 per 700 live births) and the Beckwith-Wiedemann syndrome13., 14. (incidence: 0.07 per 1000 live births).

CLASSIFICATION: AETIOLOGY

References to the aetiology of macroglossia are numerous and various classifications have been proposed due to the wide range of possible causes of the condition. Macroglossia might be congenital or acquired and may be further distinguished into hypertrophic, inflammatory or neoplastic3., 15.. However, the systematic use of such a distinction is not easy.

An aetiological classification distinguishes three types of macroglossia: true macroglossia, relative macroglossia and functional macroglossia16. In true macroglossia cases there is usually an underlying disease or syndrome that causes a pronounced tongue enlargement17. The functional type of macroglossia is due to the fact that the tongue does not properly adapt to the oral cavity after a surgical procedure that reduced the volume of the cavity18. Diagnosis of these two types is relatively easy. In cases of relative macroglossia, the tongue is slightly larger than normal and it is not easy to recognise, which usually makes diagnosis unclear19.

True or relative macroglossia may be distinguished into two main sub-types: congenital and acquired: Congenital macroglossia might be caused by idiopathic muscular hypertrophy20, adenoid hyperplasia21, haemangiomas22, lymphangiomas23, Down syndrome24, Beckwith Wiedemann syndrome25, Hurler syndrome26, Maroteux-Lamy syndrome27, Crouzon syndrome28, hypertelorism29, Becker and duch*enne dystrophies30, Pompe’s Disease31 and other causes.

In acquired macroglossia, the causes are metabolic disorders, such as hypothyroidism32, cretinism33, diabetes melitus34, acromegaly35 as well as inflammatory conditions, such as pneumonia36, glossitis37, tuberculosis38, head and neck infections23, as well as allergic reactions7, neurofibromatosis39, polymyositis40, venal congestion41, trauma42, surgical procedures43, haemorrhage44, radiation45, lymphangioma46, haemangioma47, lipoma48 and amyloeidosis49.

There are two interesting cases reports in relevant literature of two families with macroglossia due to dominant autosomal heredity50. Besides, macroglossia is an unusual but potentially fatal post-operative complication that might follow endocranial neurosurgical procedures in the posterior cranial fossa. The incidence of this complication is estimated at 1%41. Acquired macroglossia has also been reported in serum HIV positive patients due to treatment with Lopinavir and Ritonavir51.

DIAGNOSIS

Clinical diagnosis of macroglossia is not always easy, since the tongue sometimes adapts to the limited space available within the oral cavity following orthodontic treatment.52 The size of the tongue may be assessed either by direct measurement or indirectly by measuring its impression on an appropriate impression material. Recently magnetic resonance imaging (MRI) has also started being used for such measurements53.

There are various clinical and cephalometric features that can help a clinician to recognise the presence or absence of macroglossia. All these features are not always present, nor are their presence necessarily pathognomonic for macroglossia diagnosis. Clinical signs indicative of macroglossia are intensely enlarged and/or elongated, broad, flat tongue, diastema or posterior tooth spacing, mandibular protrusion, Class III malocclusion, chronic posturing of the tongue between the teeth at rest, buccal tipping of posterior teeth (increased curve of Wilson in the upper arch, reversed curve in the lower arch), accentuated curve of Spee in the maxillary arch, reversed curve of Spee in the mandibular dental arch, increased transverse width of upper and lower dento-alveolar arch, crenations on the tongue (impression marks at the points of contact with the teeth), glossitis (due to chronic mouth breathing), speech articulation disorders, assymetry in maxillary and mandibular arches (related to asymmetrical tongue), eating and swallowing difficulty, instability in orthodontic mechanics or orthognathic surgical procedures that in normal circ*mstances would be stable, respiratory problems (such as obstructive sleep apnea) and drooling5.

Besides clinical examination, there are also cephalometric radiographic radiological features that help in the diagnosis of macroglossia, such as an increased gonial angle, an increased mandibular plane angle and disproportionate mandibular growth with dentoalveolar protrusion54. In order to assess the tongue size on a lateral cephalometric radiograph, four specified points are marked on it. Using these points measurements and comparisons are performed using a commercially available transparent model-tablet which is placed on the radiograph 55. Nevertheless, some researchers claim that cephalometric assessment alone is not sufficient for the diagnosis of macroglossia56. McKenna et al. studied the morphology and structure of the tongue and claimed that no diagnostic assessment can be more effective than sound clinical examination.57 A typical clinical examination to confirm macroglossia is a patient’s capacity to extend his/her tongue so as to reach their chin or nose tip (Figure 1)5. On the other hand, in cases of edentulous patients, clinical and radiographic diagnosis of macroglossia is difficult, because dental or occlusal relations are difficult to determine58.

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Figure 1.

Patient with macroglossia who can extend his tongue to his nose tip (a) and chin (b).

A diagnostic investigation must always take into account the possibility of tongue neoplasia and in this case the role of biopsy is important. For large lesions, biopsy material harvesting is performed in the operating theatre, while for smaller lesions biopsy material may be safely harvested at the clinic or surgery, although by an experienced professional. Fine Needle Aspiration (FNA) is considered to be quite reliable as a diagnostic technique for such cases59.

Complications

An enlarged tongue may obstruct the nasopharynx and lead to total obstruction of the airway and cerebral anoxia60. Such an obstruction of the airway is usually exacerbated when the person is in a supine position, because, due to gravity, the enlarged tongue base may more easily obstruct the oropharynx and the hypopharynx61 and might even affect swallowing62.

Other morphological changes due to macroglossia include mandibular protrusion, Class III malocclusion5, anterior or/and posterior cross-bite54, impressions by posterior teeth cusps, accentuated curve of Spee in the maxillary arch, reversed curve of Spee in the mandibular arch, increased transverse maxillary and/or mandibular width2, irregular obtuse mandibular angle and increased mandibular length63 and dentoalveolar protrusion of the lower incisors (Figure 2)5. Additionally, patients have difficulty in chewing which might cause pain in the temporomandibular joint, while macroglossia may also be responsible for generalised teeth spacing (Figure 2)64., 65.. Finally, the position and size of the tongue may have a negative impact on articulation66.

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Figure 2.

Patient with macroglossia (a) that has caused anterior tooth spacing, open bite and labial tilt of anterior teeth (b).

Several authors have described the role of the tongue in the oral cavity23., 67., 68.. It is suggested that when the tongue is at rest there might well be a balance between external and internal forces exerted on the teeth69. According to Profitt70, however, teeth are subjected to a variety of forces from mastication, lips, cheeks and tongue. Whether intermittent or continuous, these forces are large enough to produce tooth movement70. A large tongue exerts force on the dental arches or interferes between them and this is considered a significant aetiological factor that causes or maintains an open bite5. Harvold, using animal studies, proved the impact of the tongue on the growth and development of jaws and dental-osseous structures71.

If true macroglossia is present along with open bite, instability of the orthognathic treatment and orthognathic surgery may be likely occur and there will be a tendency for the open bite to return5. Therefore, in some cases, tongue reduction might be necessary to ensure a positive post-treatment prognosis.

TREATMENT

The treatment of macroglossia depends on its aetiology and generally entails the correction of the systemic disease underlying the increased tongue mass, orthodontic treatment, surgery and radiotherapy. Conservative treatment includes medication, the use of leeches, apparatus application, specific training and effort to give up parafunctional habits. As for treating pseudomacroglossia, the treatment depends on its cause. For example, if the problem is caused due to distended tonsils, which force the tongue forward, then the treatment indicated is tonsilectomy so as to increase the oropharyngeal space that contains the tongue. If in another case there is a serious mandibular deficit (retrognathism-micrognathism) which creates relative macroglossia, then orthognathic surgery is indicated so as to increase the mandibular size and thus increase the volume of the oral cavity. If the aetiological factor is a cyst or a tumour, then the lesion should be excised72.

The most frequently reported treatment of macroglossia is surgery (glossectomy) which needs to be applied only in cases when the desirable effect cannot be achieved by conservative treatment. Glossectomy should be strictly selective, since the number of patients indicated for surgery is limited and probably under 10% of all patients, when their case is one of serious mandibular protrusion or/and open bite73. Indications for surgical treatment of macroglossia include: extremely sizeable tongue mass, tooth impressions on the tongue periphery, patient’s ability to extend their tongue to the chin or the nose tip, speech problems or psychological problems5. The decision to proceed to surgical treatment for macroglossia, however, needs to be based on the presence and the severity of functional deficiencies (e.g. difficulties in swallowing, speech), dentoskeletal changes due to the excessive force exercised by the tongue on surrounding anatomical structures, such as, increased mandibular angle and anterior facial height with open bite, and its psychological consequences (due to the patient’s appearance, tongue protrusion and probable involuntary salivation)74.

Many surgical techniques have been described in the literature for the treatment of glossectomy and these may be subdivided in two groups depending on the position: glossectomy along the median line and peripheral glossectomy. Both techniques entail excision of a part of the tissue and subsequent suturing of the excision margins75. Depending on the type of excision, there are different sub-types of glossectomy, such as wedge glossectomy, key-hole glossectomy, reversed key-hole glossectomy or w-shaped glossectomy.

Classical wedge glossectomy has presented very good results in recent studies67., 76.. Morgan et al. proposed key-hole shaped glossectomies16, while Harada and Enomoto described the reversed key-hole type incision77. Additionally, Mixter et al. performed W-shaped incisions24.

Most authors propose that orthodontic treatment should be performed first and only proceed with glossectomy if the tongue seems to be playing a significant role in relapsing to the pre-orthodontic treatment state. In such cases, glossectomy is performed as soon as the first relapse appears, but this is rather rare75. Furthermore, in cases of orthognathic surgery, even if the tongue is of normal size, the surgical reduction of its size might reduce the likelihood of post-operative relapse to the previous position of the mandible78.

When it is necessary to combine glossectomy with orthognathic surgery it is preferable, from an orthodontic point of view, to perform glossectomy first, followed by the surgical intervention, so that the post-operative orthodontic outcome might be more stable and predictable. An absolute indication for this sequence of events is when extensive orthodontic treatment is necessary before the orthognathic surgery and the size of the tongue impedes the required orthodontic movements. In these cases glossectomy aims to facilitate the stability of the presurgical orthodontics. The reverse sequence, i.e. orthognathic surgery followed by glossectomy would be indicated, if occlusal instability develops after orthodontics and orthognathic surgery. Additionally, the appearance of dentoskeletal changes directly related to the size of the tongue, such as open bite or a tendency for Class III malocclusion to appear, would be indications for glossectomy52. Proffit and Mason support this approach; according to them, when a sizeable tongue rests between upper and lower teeth, it may cause open bite and indicate the need for conservative or surgical treatment of macroglossia70. So, cases of open bite due to macroglossia have been reported, which, following surgical treatment of the latter, presented reduced open bite79. In other cases, the reduction of the tongue volume was followed by the use of orthodontic apparatus, i.e. chin cap, tongue crib or edgewise appliance for tooth alignment80.

Naturally, glossectomy is associated with potential risks and possible complications. These include extensive bleeding due to the rich blood supply of the tongue, airway obstruction (due to tongue oedema), tongue anaesthesia and loss of taste (due to lingual nerve injury), motor dysfunction of the tongue (due to hypoglossal nerve injury), decrease of tongue mobility (due to scarring), salivary gland duct injury, speech and mastication problems due to scarring. Furthermore, the removal of part of the tongue may affect its position at rest, which might reflect the position of the hyoid bone, as well as the mandibular position at rest. A change in muscular balance may even alter the natural head position and the position of the cervical spine81.

According to Wolford and Cottrell, following glossectomy, the lateral, downward and protrusive movements of the tongue usually remain unchanged5, while Bressman et al. support the hypothesis that good mobility of the tongue is a prerequisite condition for unimpeded speech following glossectomy82. According to Wang et al., the sense of taste and tongue mobility are rarely affected by reduction of tongue volume83. Revision surgery may be necessary if the surgical trauma does not heal due to post-surgical edema84 or if the muscular hyperplasia of the tongue persists, as in the Beckwith-Wiedemann syndrome85.

Laser use has been widely reported in the literature for the treatment of macroglossia and can be used to ensure haemostasis or to sublimate or remove tissue. Various techniques have been described mainly for CO₂ and Nd lasers86., 87.. Laser glossectomy is considered a particularly safe and reliable technique and continues to gain acceptance88., 89..

In the literature, cases of macroglossia are reported to have been successfully treated with medication. These reports concerned cases of infectious or allergic aetiology or even cases of immunodeficiency90., 91., 92..

Furthermore, in some patients, macroglossia is spontaneously corrected with growth, due to various parameters, such as more pronounced oro-facial growth or reposition of the base of the tongue23. Even the use of leeches has been reported to treat vascular congestion which might lead to macroglossia. Blood sucking by leeches results in the improvement of both the appearance and the mobility of the tongue93.

The literature also refers to the use of various orthodontic appliances for the treatment of macroglossia42., 94.. The type of appliances to be used is selected on the basis of the particular features of each case. Another technique reported is that of Castillo Morales. Although the use of this technique is considered to be treating relative macroglossia due to hypotony of the muscles, it has also been used in treating true macroglossia95.

Ruscello et al. report a different strategy for dealing with children with congenital macroglossia. After speech and eating were checked, surgery was excluded. However, the authors emphasised that, due to other features of individuals with macroglossia, it might be necessary to proceed with surgery and speech therapy later on in their lives65.

Radiation treatment is another possible solution for some forms of macroglossia. However, radiation will harm all vascular walls to a certain extent, depending on the dosage, and there might be mucosal erythema, tissue oedema, bleeding and delayed tissue healing, as well as thickening of the basal cellular membrane and extra-vascular fibrosis. Despite all these disadvantages of radiation, it still remains an effective treatment for those lesions that do not respond to other forms of treatment96.

CONCLUSIONS

Macroglossia is an anatomical disorder, the diagnosis of which is mainly determined clinically with one of its features being that the patient is capable of extending his/her tongue to their chin or nose tip. It is important that pseudo-macroglossia should be differentially diagnosed from true macroglossia, because they are treated differently. Causes leading to macroglossia might be congenital or acquired. The consequences of macroglossia usually include possible dysfunction of the orthognathic system, breathing and speech problems, increased mandibular size, open bite, tooth spacing and other dentoskeletal problems. Macroglossia treatment depends on its aetiology and includes the correction of the underlying systemic disease, if that is the case, surgery and radiotherapy.

REFERENCES