Primary Mandibular Tuberculous Osteomyelitis Mimicking Ameloblastoma: A Case Report and Literature Review of Mandibular Tuberculous Osteomyelitis

Primary tuberculous osteomyelitis involving the mandible represents less than 2% of skeletal locations. In this paper, we report a case of mandibular tuberculosis (TB) detected after histopathological analysis of the surgically resected specimen during surgical management of a suspected case of ameloblastoma. A 14-year-old male patient presented to us with history of right-sided chin swelling. The clinical examination revealed a swelling, involving right body and parasymphysis of mandible, measuring approximately 6 cm in length and 2 cm in width, extending from right lateral incisor till the first molar. Radiological scans revealed a large multiloculated osteolytic expansive lesion measuring 52 × 20 × 18 mm. Excision of the lesion was performed and reconstruction was done with iliac bone grafting. The histopathological findings revealed a granulomatous lesion, suggestive of tuberculous osteomyelitis. The patient was successfully treated with standard multidrug therapy. One year after completion of therapy, there were no signs of recurrence. Primary mandibular TB is an extremely rare entity. Its clinical presentation is not specific. Radiologically, TB has no characteristic appearance. The positive diagnosis is based on histology. Primary mandibular TB is rare and should be kept among differential diagnoses in susceptible population and in endemic areas.


Introduction
Primary tuberculosis (TB) of the mandible is rare.2][3] TB of the mandible usually presents as a part of multifocal lesions in the body, involving other bones and lungs. 4A total of 1.6 million people died from TB in 2021 (including 187,000 people with HIV).In 2021, an estimated 10.6 million people were infected with TB worldwide. 5Mandibular TB is uncommon and often diagnosed late because of nonspecific clinical presentation and the absence of pathognomonic signs. 6,7The mainstay of treatment is antitubercular multidrug therapy.Surgery is indicated in only some cases. 8,9We report the case of a 14-year-old male patient managed for mandibular swelling, with provisional diagnosis of benign mandibular etiology, likely ameloblastoma.Primary mandibular TB was detected incidentally on the histopathological examination. 10ase A 14-year-old male patient presented to us with a history of painless, gradually increasing swelling on the right side of chin for 1 year (►Fig.1A-D).He did not have any history of trauma, discharge, sinus, or redness in the region or any sudden increase in size.There was a scar of previous biopsies over the right side of his chin.There was no history of TB or family history of any chronic disease.Clinical examination revealed a swelling involving right parasymphysis and body of mandible, measuring approximately 6 cm in length and 2 cm in width, extending from right lateral incisor till the first molar, with normal overlying skin.On palpation, the swelling was firm in consistency.It was noncompressible, nonfluctuant, and slightly tender.The oral examination of the patient showed good mouth opening with normal occlusion and fair hygiene.His canine and first premolar over the involved bone were loose.There were no palpable lymph nodes.Systemic examination was normal.
The blood investigations and serology were within normal limits.The orthopantomogram (►Fig.2A) showed a multilocular osteolytic lesion involving the right parasymphysis and body of the mandible.Computed tomography (CT) scan (►Fig.2B-F) revealed a large multiloculated osteolytic expansive lesion arising from the right parasymphysis and body of mandible measuring 52 Â 20 Â 18 mm.The posterior cortex was not involved by the disease process.No enlarged lymph nodes were identified.The patient had undergone biopsies of the lesion at two different centers on separate occasions.These biopsies did not show any cellular atypia.However, they were inconclusive for any definitive ethology.Chest X-ray was found to be normal.Positron emission tomography scan was donelytic lesion is noted in body of right mandible with soft tissue and fat stranding-there is significant cortical breech and minimal periosteal reaction known as osteomyelitis involvement.Few tiny, right-sided, cervical level IB, Il and Bilateral level V nodes are noted and appeared reactive.Enlarged prevascular lymph node is noted measuring 2.0 Â 1.5 cm; similar left-sided hilar node is also noted.Rest of the bones were visualized and bilateral lungs appeared unremarkable.Remainder of the survey showed unremarkable tracer distribution.Our provisional diagnosis was benign mandibular ethology, likely ameloblastoma.
Informed consent was taken from the patient and his father for publication.The surgical management involved excision of the lesion with external approach (►Fig.3A).The specimen   Corticocancellous iliac crest bone graft, measuring 5.5 Â 2 cm was used for reconstruction of the defect (►Fig.3C).A single, continuous, 2.5-mm miniplate was used for fixation of bone graft using 2.5-mm screws (►Fig.3D).The postoperative period was uneventful.
The histopathological analysis of the excised specimen revealed a granulomatous lesion, consistent with tuberculous osteomyelitis.On gross examination, a 1.6 Â 1.2-cm cystic cavity was seen at one extreme, lined by necrotic material.On microscopy, multiple sections showed epithelioid granulomas, giant cells, and caseous necrosis.Necrotic bone was noted.Patient was started on category I of antituberculosis therapy (ATT) as per The National Tuberculosis Elimination Programme regimen.It included intensive phase therapy for 2 months, consisting of rifampicin, isoniazid, pyrazinamide, and ethambutol, followed by rifampicin, isoniazid, and ethambutol as continuation phase therapy for 4 months.
On follow-up (►Fig.1E-H) at 1 year after completion of ATT (18 months after surgery), the patient had no complaints and no evidence of recurrence.He has good mouth opening, normal occlusion, and good aesthetic outcome.Radiological evaluation (►Fig. 4)showed integration of bone graft.Patient is now being worked up for dental rehabilitation.

Discussion
Ameloblastoma is a benign odontogenic tumor. 11It is usually asymptomatic but when it attains considerable size, it can present with jaw expansion.Radiologically, it shows an osteolytic pattern.Approximately 80% of these tumors are found in the mandible, but the maxilla is infrequently affected. 12ral TB may manifest as swelling, pain, loosening of teeth, displacement of tooth buds, ulcers, granulomas, involvement of salivary glands and temporomandibular joint, and tuberculous lymphadenitis. 13The lesions of primary orofacial TB could be the only presentation of the disease. 14Primary TB of the mandible is an uncommon entity which represents less than 2% of all skeletal TB. [1][2][3] As the mandible contains less cancellous bone, the chances of involvement of the mandible are very less in comparison to maxilla, except that the alveolar and angle regions have greater affinity. 15In orofacial region, the mandible is affected more often than the maxilla and the angle and alveolus of the mandible are commonly affected areas. 7ifferent mechanisms of extension of the infection to the mandible involve direct inoculation through dental extraction or lesions of mucosa or perforation of an erupting tooth, extension from a nearby soft tissue lesion which involves the underlying bone and hematogenous seeding. 16,17Mandibular TB is often difficult to diagnose because of the uncommon and nonspecific presentation and absence of pathognomonic signs.In a few cases, it appears as an acute inflammatory swelling. 7In countries like India, TB can never be left out of the differential diagnoses.Elzouiti et al reported a patient of ameloblastoma whose mandibular TB was diagnosed incidentally on histopathology, which is extremely rare. 6    Radiologically, there is no characteristic appearance of TB. 16 Mandibular TB starts as an area of rarefaction and trabecular blurring.Slowly, there is erosion of cortical bone and it is replaced by soft granulation tissue and subsequently subperiosteal abscess formation takes place ending with a visible painful swelling.Pathological fractures of the mandible or sequestration have also been reported. 18he cases with minimally destructive lesions of TB can be managed by ATT.The medical treatment includes rifampicin, isoniazid, pyrazinamide, and ethambutol initially as an intensive phase regimen followed by rifampicin, isoniazid, and ethambutol as continuation phase for a total period of 6 to 18 months with clinical and biological monitoring. 19Surgical modalities described are for abscess developing in the soft tissue and removal of the sequestered necrotic bone.Decortication of bone is indicated for moderately destructive lesions because of medullary bone destruction and/or cortical bone perforation. 2Early detection of the disease results in complete cure and can lead to reversal of all destructive bony changes.If detected late, this can lead to serious complications like tuberculous meningitis. 4ifficulty in differentiating primary tuberculous osteomyelitis of mandible from ameloblastoma stems from the fact that both can present as slowly growing expansile osteolytic lesion in the mandible.Discharging sinuses and signs of TB elsewhere in body may point to tuberculous osteomyelitis.But as in our case, primary tuberculous osteomyelitis of mandible may present without any of these.Bone sequestration, abscess formation are common in tuberculous involvement, however these are not pathognomic and can rarely be found in ameloblastoma.Definitive diagnosis in absence of systemic findings of TB rests on histopathological examination.
We have carried out a review of 20 cases of primary TB of the mandible (►Fig. 5,[20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] We excluded all the cases which had signs of secondary involvement of the mandible and included cases which had no signs suggestive of TB anywhere else in the body.Although tuberculous osteomyelitis is more prevalent in endemic areas, it is present all over the world and among all age groups.It usually begins as a localized swelling and is associated with pain and enlarged cervical lymph nodes.While cytological examination is mostly inconclusive, biopsy could provide the necessary information to diagnose tuberculous osteomyelitis.However, biopsy is not always conclusive for TB, like in our scenario.Radiological imaging with findings like radiolucency, bone destruction, osteolytic and expansile bone lesions or sequestrum should raise the suspicion of osteomyelitis.In cases with raised erythrocyte sedimentation rate and positive tuberculin test, along with findings of osteomyelitis on imaging and pathological examination, one should always rule out TB in endemic regions.We observed that ATT was sufficient for complete resolution of the symptoms in most of the studies.Surgery was done in cases where there was diagnostic uncertainty.

Conclusion
We have shared our experience of incidental detection of primary mandibular TB in a patient presenting with ameloblastoma-like picture.Clinical and radiological presentation of primary mandibular TB is not specific, making it a diagnostic challenge for clinicians.The histopathologic analysis is diagnostic for tuberculous osteomyelitis.It should form a part of differential diagnoses in endemic areas.If biopsy reveals tuberculous osteomyelitis, ATT can avoid the need of surgical intervention.

Fig. 2
Fig. 2 Radiological investigations.(A) Preoperative orthopantomogram showing the multilocular osteolytic lesion of right parasymphysis and body of mandible.(B) Cone beam CT showing the lytic lesion involving right side of the mandible from lateral incisor till first molar.(C) CT three-dimensional reconstruction showing multiloculated osteolytic expansive lesion arising from the right parasymphysis and body of mandible.(D) CT plate showing involvement of anterior cortex of mandible.(E) CT plate showing sparing of posterior cortex of mandible.(F) CT plate showing involvement of right side of the mandible from lateral incisor till first molar.CT, computed tomography.Archives of Plastic Surgery Vol.51 No. 2/2024 © 2024.The Author(s).

Primary
Mandibular Tuberculosis Chalwade et al. 189 was greyish, gritty, and with destruction of the anterior cortex of the mandible.The canine and first premolar were involved.The specimen measurements were 5 Â 2 Â 1.8 cm (►Fig.3B).

Fig. 5
Fig. 5 Comparative chart showing the number of patients with various findings in terms of enlarged lymph nodes, radiological finding, FNAC, biopsy, evidence pointing towards TB, gender and age of the patient.ESR, erythrocyte sedimentation rate; TB, tuberculosis; yrs, years; FNAC, fine needle aspiration cytology.