Large erupted complex odontoma mimicking maxillary osteomyelitis

Abstract

Odontoma is the most common benign odontogenic hamartoma. Odontomas are of two types, such as viz compound and complex odontoma. The complex type is a conglomeration of hard tissues of dental origin. They are primarily intraosseous and usually present in the second decade of life. Most odontomas are asymptomatic, but those erupting in the oral cavity may cause severe infection. They are often associated with impacted teeth and are present with the anterior maxilla showing the highest propensity.

The present case report is of a male patient in his early 60s with a substantial solitary sclerotic odontoma of the middle and posterior segments of the maxilla erupted into the oral cavity communicating with the right maxillary sinus. The delayed presentation, size, location and active suppuration can misguide clinicians.

Background

The present case reports a rare case of erupted paranasal sinus tumour. It is an infrequent entity and was seen to involve a significant part of the maxillary bone. The tumour was a hamartomatous growth composed of enamel, dentin, cementum and pulp. According to the WHO classification of 2017, there are two types of odontomas, such as complex and compound odontomas.¹ Patients presenting with odontomas are always symptomless but often associated with teeth eruption disturbances. Usually, the odontomas are diagnosed on routine examination due to their intraosseous location. Still, some odontomas appear in the oral cavity due to the eruptive forces offered by perilesional reactive tissue. Complex odontoma is a conglomeration of enamel and dentine matrix, that is, although indigenous to alveolar complex, not organised into definite layers. The compound odontomas resemble more normal tooth anatomy with the deposition of distinct layers of enamel and dentine but vary in morphometrics.² Odontoma can be associated with an impacted tooth, and susceptibility to secondary infection in a bone-covered tumour has rarely been reported; however, the erupted forms can be secondarily infected due to oral microflora. The treatment is quite simple and resolves after simple surgical excision of the tumour with negligible recurrence potential.²

Case presentation

An elderly man in his 60s reported with a mass in his upper right side visible intraorally for over 45 years. The patient gave a history of yellowish-brown mass being present without change in size and shape over the years. His early childhood trauma with baseball was reported over the right side of the face, accompanied by swelling and pain. There was a discharging sinus tract for which the patient had undergone treatment at the time of trauma.

On extraoral examination, there was mild facial asymmetry on the right side with no changes in the overlying skin (figure 1). Intraorally, the lesion was grossly irregular, extending anteroposteriorly from the right maxillary canine to the right maxillary tuberosity, mediolaterally obliterating the buccal vestibule with mild involvement of the palatine bone. Oroantral communication was confirmed with the regurgitation of fluids (figure 2).

Figure 1.

Preoperative image showing a scar and gross facial asymmetry of right side of face.

Figure 2.

Intraorally erupted complex odontoma with irregular hard calcified surface.

General medical examination revealed hemiparesis of the left side associated with a history of cerebrovascular accident, circular red, itchy and patchy lesions of the lower abdomen, groin and inner thighs more likely to be a concurrent fungal infection, the dorsal surface of the anterior two-thirds of the tongue showed bull’s eye lesions, multiple skin tags were also evident in the axillary region. The signs did not indicate any known syndrome, thus negating any possible association. The patient had a history of past COVID-19 infection, although it did not require oxygen and steroidal therapy.

History of recurrent swelling, pus discharge, inflamed gingival tissue associated with pain masqueraded like an exposed bony necrotic sequestrum of odontogenic origin leading to a differential diagnosis of chronic suppurative osteomyelitis of right maxilla due to traumatic aetiology.

No history of dental extraction was reported, and no evident maxillary posterior dentate structures were present.

Compiling clinical and radiographic findings established the working diagnosis of chronic osteomyelitis with exposed necrotic right maxillary bone. Differential diagnosis of an odontogenic tumour of the maxillary sinus and fibro-osseous lesion was also sought-after confirmation of missing permanent teeth buds on CT. The recommended intervention was an urgent need for surgical debridement using the intraoral approach with excision of the surrounding inflamed cuff of tissue and sinus lavage.

The working diagnosis of chronic osteomyelitis with suppuration was justifiable.

Investigations

Non-contrast CT of the face revealed a radiopaque mass of the right maxillary sinus with a radiolucent halo representing the residual sinus cavity. The surrounding sinus mucosa was minimally inflamed and thickened. There were signs of subperiosteal reactive bone formation with a breach of anterior and posterior walls and floor of the maxillary sinus. The lesion was confirmed to communicate with the oral cavity (figures 3 and 4).

Figure 3.

Axial section of non-contrast CT. face showing radiodense lesion within the right maxillary sinus.

Figure 4.

Coronal section of NCCT face showing radiopaque lesion extending up to the floor of orbit. NCCT, non-contrast CT.

The sample obtained was sent for histological analysis and potassium hydroxide mount to rule out fungal osteomyelitis. No fungal hyphae were detected. The tumour was reported to be aseptic necrosis with bony trabeculae by a medical pathologist, initially adding to perplexity. The histological examination by a maxillofacial pathologist established the diagnosis of complex odontoma of the posterior maxilla (figure 5). Thus, what was considered to be infective osteomyelitis of the jaw had proven to be a secondarily infected odontogenic tumour.

Figure 5.

Photomicrograph of H&E-stained decalcified section showing dentin arranged in irregular manner with interspersed numerous empty spaces representative of enamel.

Differential diagnosis

Differential diagnosis of osteoma, osteonecrosis and the fibro-osseous lesion was negated based on the presence of perilesional halo, no associated history of radiation and medication related to the tooth structure, respectively. The possibility of a wide variety of other tumours of odontogenic epithelium origin could not be ruled out clinically.

Due to the prevailing post-COVID-19 mucormycosis endemic in India and the injudicious use of antibiotics, steroids and non-modifiable immunocompromised state in the geriatric group, a differential diagnosis of maxillary osteomyelitis secondary to Mucor was considered. The incidence of such cases without comorbidity was also reported during the endemic.

Treatment

The lesion extended up to the orbit floor without any erosion on surgical exploration done under general anaesthesia on an inpatient basis. The lesion was removed in toto using the existing defect with a small releasing incision extending onto the palate (figure 6). The lesion could be easily separated along its junction of normal surrounding mucosa with bimanual mobilisation. The lesion’s foul smell and darkened appearance at the base were additionally noted. Closure of the lesion was done with a surgical obturator until the signs of infections subsided with empirical antibiotics (injection amoxicillin+clavulanic acid 1.2 g, injection metronidazole 500 mg intravenously). The sinus wall had healthy granulation tissue at the follow-up with no signs of recurrence or residual tumour mass (figures 7 and 8). Definitive closure of the defect was done with a buccal myomucosal flap at a later stage (figure 9). A multidisciplinary team approach helped resolve coexisting fungal infection of the thighs using topical antifungals, and tongue lesions subsided spontaneously.

Figure 6.

The excised sample measuring 7×5×7 cm in dimension.

Figure 7.

Follow-up orthopantomogram showing no residual tumour mass.

Figure 8.

Follow-up image showing oroantral defect of right hemimaxilla.

Figure 9.

Postoperative follow-up after definitive closure.

Outcome and follow-up

• Closure of the defect helped resolve the oroantral communication.

• No recurrence of the lesion or presence of residual lesion was noted after 1 year of follow-up.

Discussion

Complex odontoma is a painless tumour of odontogenic origin. Despite being quite prevalent, it usually does not exceed the size of a tooth on most clinical presentations and is discovered on routine examination.

Budnick found that 61% of the cases of odontomas are usually associated with impacted teeth.² The origin of a complex odontoma is unknown, and some suggest trauma or infection be the cause. In the present case, the patient had a history of trauma with a baseball in his early childhood and developed a swelling with a draining sinus tract and active pus. There are incidences of a large solitary odontoma of the posterior mandible, but a lesion of the posterior maxilla is exceedingly rare.³

There are two types of odontomas, such as complex odontomas and compound odontomas. Compound odontomas show a predilection for the anterior sector of the upper maxilla. They are twice as common compared with the former. In contrast, complex odontomas are often found in the posterior mandibular region, thereby making the posterior maxilla, in our case, an unusual site of presentation.^{4 5} Odontomas are mostly diagnosed during the first two decades of life in the literature review by Zhuoying and Fengguo⁶ and the present case due to delayed presentation is the oldest reported case in the seventh decade of life.

In a retrospective study by Isola et al,⁷ it was found that clinical characteristics ranged from the delayed eruption of permanent teeth pain, swellings and sometimes no symptoms. Most of the patients were incidentally diagnosed with odontoma on a routine radiograph. The mean age of presentation is 15 years, mostly near the incisive region in 20% of cases and less than 15% in the posterior maxilla when the lesion involves the maxilla. In a meta-analysis by Hidalgo-Sánchez et al,¹ agenesis of permanent teeth was found in 7.2% of cases only.

It has been stated that the radiologic manifestation of an odontoma is unique even on plain film radiographs like an orthopantomogram appearing as a hyperdense, non-cystic, well-defined mass with a radiolucent margin.⁸ The associated history of physical trauma to the maxilla with active pus discharge intraorally on presentation is gimmicked like bony infection with exposed necrotic bone requiring debridement. CT revealed the absence of the maxillary sinus anterior, posterior walls and floor with a radiopaque filling surrounded by a radiolucent area with minimal mucosal thickening. The central mass of radiopacity presented like a bony sequestrum with increased calcification.

Suppurative osteomyelitis is primarily due to odontogenic infections characterised by pus, fistula and sequestrations.⁹ According to Mac Beth, maxillary osteomyelitis is classified as traumatic (following surgery or injury with the primary site of infection being antrum, teeth or lacrimal sac), rhinogenic (spontaneous spread of infection from antrum and postoperative rhinogenic cases) and odontogenic (root sepsis).¹⁰

The lesion, in our case, is not related to dentate structure and clinically presents as exposed necrotic bone. There were multiple missing posterior teeth of the right maxilla confirmed radiographically, with no history of dental extraction reported. In the most cases of odontoma, the lesion is pericoronal to the impacted tooth. However, other non-odontogenic expansile lesions of the bone can be easily differentiated by the presence of a perilesional halo found in odontoma.¹¹

Complex odontomas are associated with alterations in tooth eruption patterns, with an incidence of association ranging from 41%, according to Katz¹² in a series of 396 odontomas to 87%, according to Tomizawa et al.¹³

The trauma in the developing stage of the tooth bud could be hypothesised for leading to the formation of an amorphous hyperattenuating conglomerate mass of enamel and dentin in our case. The added peculiarity is the size ranging from about 7 cm (anteroposteriorly) to 5 cm (mediolaterally), with a height of 7 cm contained in the maxillary sinus. Such a large, erupted solitary complex odontoma of the maxilla in the oral cavity has not been reported yet. In a study by López-Areal et al,¹⁴ they found that a child developed multiple odontomas after experiencing trauma with the intrusion of incisor teeth at the age of 10 months.

Recurrent infection following eruption has been reported.¹⁵ This recurrent infection can resorb the surrounding maxillary sinus walls and lead to the thickening of mucosal tissue, further increasing the exposure. However, it cannot be determined whether infection led to the conglomerate’s exposure or its antagonistic origin. The present case also shows suppuration with its exposure to the oral cavity.

Erupting odontomas are uncommon, with the first report in 1980.¹⁶ The reason for eruptive forces can be ascribed to impacted teeth. However, due to the absence of tooth buds, remodelling of alveolar bone, sequestration of surrounding bone or reactive growth of the capsule encapsulating an odontoma may contribute to this phenomenon. The suggested reasons for the eruption of odontoma do fit well with the present case. It differs from the regular eruptive forces generated by the root development and periodontal ligament, thus varying from the inherent contractility of fibroblasts as in normal dentition.

Odontomas are common tumours that can be easily diagnosed and treated by surgical excision. However, it becomes difficult to establish a clinical diagnosis once it erupts until histologically proven. This case is an aberration from the usual age characteristics and has presented a significant diagnostic challenge. Compilation of essential features like the age of the initial onset of the lesion can only aid in arriving at a diagnosis in an elderly patient.

Learning points.

• The rarity lies in the multiple clinical characteristic presentations viz the geriatric age group, history of COVID-19 infection, absence of permanent teeth and a large portion of the lesion erupted into the oral cavity with recurrent signs of infection.

• This case report broadens the spectrum of age in which the lesion usually occurs.

• Radiographically, a complex odontoma is usually an intraosseous tooth-related sclerotic hamartoma with a conglomeration of enamel and dentin located pericoronally with an impacted tooth. The presentation here is atypical.

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