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A rare mandibular tumour
G Model ANORL-626; No. of Pages 4
ARTICLE IN PRESS European Annals of Otorhinolaryngology, Head and Neck diseases xxx (2016) xxx–xxx
Available online at
ScienceDirect www.sciencedirect.com
What is your diagnosis?
A rare mandibular tumour H. Touil ∗ , J. Hamila , M. Bouzaiene Service de stomatologie et de chirurgie maxillo-faciale, hôpital Tahar Sfar, Hiboun, 5111 Mahdia, Tunisia
1. Case report A 54-year-old man with no notable medical history presented with isolated paraesthesia of the right half of the lower lip. This symptom had been present for six months. Clinical interview did not reveal any history of mandibular injury or dental care or systemic disease. Clinical examination did not reveal any mucocutaneous lesions. Mouth opening was normal and no bone swelling or lymph nodes were demonstrated on palpation of the neck. The imaging assessment demonstrated a unilocular defect, clearly visible on panoramic computed tomography. This clearly
demarcated lesion was associated with peripheral opacity situated over the projection of the inferior dental canal, which appeared to be enlarged (Fig. 1a). A 2-cm finger-like image was also observed in the inner cortex of the right pre-angular mandibular region, visible on the three-dimensional reconstruction (Fig. 1b). 2. Questions What are the possible diagnoses? What management would you propose?
∗ Corresponding author. Tel.: +00216 55 251 842; fax: +00216 73 671 579. E-mail address: [email protected] (H. Touil). http://dx.doi.org/10.1016/j.anorl.2016.11.010 1879-7296/© 2016 Elsevier Masson SAS. All rights reserved.
Please cite this article in press as: Touil H, et al. A rare mandibular tumour. European Annals of Otorhinolaryngology, Head and Neck diseases (2016), http://dx.doi.org/10.1016/j.anorl.2016.11.010
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Fig. 1. a: CT scan showing osteolysis continuous with the inferior alveolar canal; b: 3D CT scan showing rounded osteolysis of the pre-angular region of the mandible.
What is your diagnosis?
Please cite this article in press as: Touil H, et al. A rare mandibular tumour. European Annals of Otorhinolaryngology, Head and Neck diseases (2016), http://dx.doi.org/10.1016/j.anorl.2016.11.010
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ARTICLE IN PRESS H. Touil et al. / European Annals of Otorhinolaryngology, Head and Neck diseases xxx (2016) xxx–xxx
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3. Answer The slow course and the radiological appearance are suggestive of a benign tumour, such as bone lipoma, mandibular cyst or schwannoma. However, a malignant tumour cannot be excluded. Surgical decompression of the inferior alveolar nerve is indicated due to the presence of paraesthesia. We performed an inferior vestibular nerve approach extending over the external oblique ridge of the mandible, which allowed detachment of a mucoperiosteal flap over the right ramus. Intraoperative exploration did not reveal any periosteal reaction or cortical thinning or destruction. A cortical bone window was created underneath the roots of the premolars and molars followed by resection of the pathological tissue and cautious curettage, while sparing the inferior alveolar nerve in the ramus (Fig. 2). The mucosal flap was repositioned and sutured. Cancellous bone fragments and tumour tissue, with a fatty macroscopic appearance, were sent for histological examination which concluded on a diagnosis of mandibular intraosseous lipoma (Fig. 3). The postoperative course was marked by resolution of paraesthesia after three weeks. No recurrence has been observed with a follow-up of 2 years. Despite the abundance of intraosseous adipose tissue, lipomas and particularly intramedullary lipomas are rare bone tumours [1,2], representing only 0.1 to 2.5% of all primary bone tumours [2,3]. However, the incidence of these tumours may be severely underestimated in view of their frequently insidious clinical features. Furthermore, even when the tumour is detected, the diagnosis may be difficult to establish due to the marked heterogeneity of radiological and histopathological findings [2]. Intraosseous lipoma was reported for the first time in 1880 in the femur [4] and only about twenty cases of this tumour have subsequently been reported in the extremities. The head and neck is an exceptional site, but several rare cases have been reported in the maxillary molar region [1].
Fig. 2. Intraoperative photograph showing the residual cavity.
Fig. 3. Microscopic appearance of the tumour showing adipose tissue (HE stain × 100).
Intraosseous lipoma is a slow-growing benign tumour, composed of a mass of mature cells [4]. Intraosseous lipoma may be either intramedullary or intracortical [4]. This tumour can be observed at all ages, but predominantly in men between the ages of 30 and 60 years [2–4], which could support the hypothesis that this tumour is secondary to intraosseous fatty degeneration. The aetiopathogenesis of this tumour remains uncertain [2,4], but several hypotheses have been proposed. The most widely accepted hypothesis is that of a post-traumatic secondary bone reaction [4], although clinical interview generally does not reveal any history of injury [2]. The other hypotheses involve degeneration or necrosis [2]. However, the presence of cortical expansion, observed in more than one-half of cases, is not in favour of this hypothesis. Clinically, intraosseous lipoma can present with bone swelling [2,4], pain [2–4], neurological signs due to nerve compression, such as paraesthesia or sensory loss, as reported by our patient. However, this tumour can also be asymptomatic [1,3] with incidental discovery in 25 to 40% of cases [2]. The radiological features vary according to the stage of the tumour. Classically, conventional radiology shows a clearly demarcated filling defect of variable dimensions, suggesting a benign odontogenic tumour or cystic lesion [2]. However, large lipomas can be associated with thinning or sometimes even destruction of the cortex or periosteal reaction, resulting clinically in pain and swelling. Computed tomography demonstrates a fat-filled defect with negative densities, sometimes associated with calcifications with densities of 0 to 20 Hounsfield Units. MRI plays a major role in the diagnosis and is the most appropriate examination to characterize this tumour and eliminate certain differential diagnoses. MRI typically shows a lesion with a hypointense T1 signal, an intermediate T2 signal, and a hypointense signal on fat saturation sequences (STIR, T2 FAT-SAT). Calcifications, bony trabeculae and marginal osteosclerosis appear hypointense on all sequences. Several stages of intraosseous lipoma have been described on the basis of radio-histological correlations [2–4]. Stage 1: osteolytic image corresponding to a tumour composed of live adipocytes.
Please cite this article in press as: Touil H, et al. A rare mandibular tumour. European Annals of Otorhinolaryngology, Head and Neck diseases (2016), http://dx.doi.org/10.1016/j.anorl.2016.11.010
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ARTICLE IN PRESS H. Touil et al. / European Annals of Otorhinolaryngology, Head and Neck diseases xxx (2016) xxx–xxx
Stage 2: central calcification is observed within the osteolytic lesion with zones of fat necrosis due to focal ischaemia secondary to compression of capillaries. The associated peripheral osteosclerosis corresponds to a reaction of normal bone in contact with the tumour. Stage 3: ischaemic bone becomes more extensive, associated with images of reactive new bone formation. The differential diagnosis includes solitary bone cyst, classically observed in adolescents, and pseudocyst, which generally has less clearly defined margins. The other differential diagnoses include certain benign odontogenic tumours (myxoma), as well as bone infarction, fibrous dysplasia, osteoporosis and malignant odontogenic tumours, osteoblastoma, chondrosarcoma, or liposarcoma [4]. The fat density visible on the radiological assessment can guide the diagnosis, but the intraoperative findings and the macroscopic appearance are sometimes nonspecific [1,3]. The definitive diagnosis is based on histopathology [1,3–5], which confirms the presence of lamellar bone surrounding a central zone of adipose tissue [1] with no cellular atypias [2,4]. Histological proof is mandatory to exclude a malignant tumour. In the case reported here, inferior alveolar nerve decompression restored normal sensation. The diagnosis was only established on the basis of histopathological examination, showing adipose infiltration with rarefaction of bony trabeculae. Curative treatment is surgical [4] and is recommended in symptomatic forms [3]. A favourable course with resolution of the clinical features is generally observed [2].
Malignant transformation of mandibular intraosseous lipoma has not been reported in the literature [4]. 4. Conclusion Intraosseous lipoma must be considered in the differential diagnosis of benign tumours of the mandible. Certain malignant tumours must also be eliminated, especially in symptomatic patients. Histopathological examination is therefore required to establish the definitive diagnosis. Disclosure of interest The authors declare that they have no competing interest. References [1] Morais AL, Mendonc¸a EF, Gonc¸alves de Alencar AH, Estrela C. Intraosseous lipoma in the periapical region of a maxillary third molar. J Endod 2011;37: 554–7. [2] Aumar DK, Dadjo YB, Chagar B. Intraosseous lipoma of the calcaneus: report of a case and review of the literature. J Foot Ankle Surg 2013;52:360–3. [3] Bonnin Vilaplana M, Simón Adiego C, Molins López-Rodó L. Intraosseous lipoma of rib. Arch Bronconeumol 2005;41:236–7. [4] Shaini B, Jerly A, Shameena PM, Balan A. Intraosseous lipoma of mandible presenting as a swelling. J Oral Maxillofac Pathol 2013;17:126–8. [5] Zhu B, Liu XG, Liu ZJ, Liao HI, Jiang L, Wei F. Intraosseous lipoma of adjacent upper cervical vertebral bodies with significant paravertebral expansion. Chin Med J 2010;123:3160–2.
Please cite this article in press as: Touil H, et al. A rare mandibular tumour. European Annals of Otorhinolaryngology, Head and Neck diseases (2016), http://dx.doi.org/10.1016/j.anorl.2016.11.010
ARTICLE IN PRESS European Annals of Otorhinolaryngology, Head and Neck diseases xxx (2016) xxx–xxx
Available online at
ScienceDirect www.sciencedirect.com
What is your diagnosis?
A rare mandibular tumour H. Touil ∗ , J. Hamila , M. Bouzaiene Service de stomatologie et de chirurgie maxillo-faciale, hôpital Tahar Sfar, Hiboun, 5111 Mahdia, Tunisia
1. Case report A 54-year-old man with no notable medical history presented with isolated paraesthesia of the right half of the lower lip. This symptom had been present for six months. Clinical interview did not reveal any history of mandibular injury or dental care or systemic disease. Clinical examination did not reveal any mucocutaneous lesions. Mouth opening was normal and no bone swelling or lymph nodes were demonstrated on palpation of the neck. The imaging assessment demonstrated a unilocular defect, clearly visible on panoramic computed tomography. This clearly
demarcated lesion was associated with peripheral opacity situated over the projection of the inferior dental canal, which appeared to be enlarged (Fig. 1a). A 2-cm finger-like image was also observed in the inner cortex of the right pre-angular mandibular region, visible on the three-dimensional reconstruction (Fig. 1b). 2. Questions What are the possible diagnoses? What management would you propose?
∗ Corresponding author. Tel.: +00216 55 251 842; fax: +00216 73 671 579. E-mail address: [email protected] (H. Touil). http://dx.doi.org/10.1016/j.anorl.2016.11.010 1879-7296/© 2016 Elsevier Masson SAS. All rights reserved.
Please cite this article in press as: Touil H, et al. A rare mandibular tumour. European Annals of Otorhinolaryngology, Head and Neck diseases (2016), http://dx.doi.org/10.1016/j.anorl.2016.11.010
G Model ANORL-626; No. of Pages 4 2
ARTICLE IN PRESS H. Touil et al. / European Annals of Otorhinolaryngology, Head and Neck diseases xxx (2016) xxx–xxx
Fig. 1. a: CT scan showing osteolysis continuous with the inferior alveolar canal; b: 3D CT scan showing rounded osteolysis of the pre-angular region of the mandible.
What is your diagnosis?
Please cite this article in press as: Touil H, et al. A rare mandibular tumour. European Annals of Otorhinolaryngology, Head and Neck diseases (2016), http://dx.doi.org/10.1016/j.anorl.2016.11.010
G Model ANORL-626; No. of Pages 4
ARTICLE IN PRESS H. Touil et al. / European Annals of Otorhinolaryngology, Head and Neck diseases xxx (2016) xxx–xxx
3
3. Answer The slow course and the radiological appearance are suggestive of a benign tumour, such as bone lipoma, mandibular cyst or schwannoma. However, a malignant tumour cannot be excluded. Surgical decompression of the inferior alveolar nerve is indicated due to the presence of paraesthesia. We performed an inferior vestibular nerve approach extending over the external oblique ridge of the mandible, which allowed detachment of a mucoperiosteal flap over the right ramus. Intraoperative exploration did not reveal any periosteal reaction or cortical thinning or destruction. A cortical bone window was created underneath the roots of the premolars and molars followed by resection of the pathological tissue and cautious curettage, while sparing the inferior alveolar nerve in the ramus (Fig. 2). The mucosal flap was repositioned and sutured. Cancellous bone fragments and tumour tissue, with a fatty macroscopic appearance, were sent for histological examination which concluded on a diagnosis of mandibular intraosseous lipoma (Fig. 3). The postoperative course was marked by resolution of paraesthesia after three weeks. No recurrence has been observed with a follow-up of 2 years. Despite the abundance of intraosseous adipose tissue, lipomas and particularly intramedullary lipomas are rare bone tumours [1,2], representing only 0.1 to 2.5% of all primary bone tumours [2,3]. However, the incidence of these tumours may be severely underestimated in view of their frequently insidious clinical features. Furthermore, even when the tumour is detected, the diagnosis may be difficult to establish due to the marked heterogeneity of radiological and histopathological findings [2]. Intraosseous lipoma was reported for the first time in 1880 in the femur [4] and only about twenty cases of this tumour have subsequently been reported in the extremities. The head and neck is an exceptional site, but several rare cases have been reported in the maxillary molar region [1].
Fig. 2. Intraoperative photograph showing the residual cavity.
Fig. 3. Microscopic appearance of the tumour showing adipose tissue (HE stain × 100).
Intraosseous lipoma is a slow-growing benign tumour, composed of a mass of mature cells [4]. Intraosseous lipoma may be either intramedullary or intracortical [4]. This tumour can be observed at all ages, but predominantly in men between the ages of 30 and 60 years [2–4], which could support the hypothesis that this tumour is secondary to intraosseous fatty degeneration. The aetiopathogenesis of this tumour remains uncertain [2,4], but several hypotheses have been proposed. The most widely accepted hypothesis is that of a post-traumatic secondary bone reaction [4], although clinical interview generally does not reveal any history of injury [2]. The other hypotheses involve degeneration or necrosis [2]. However, the presence of cortical expansion, observed in more than one-half of cases, is not in favour of this hypothesis. Clinically, intraosseous lipoma can present with bone swelling [2,4], pain [2–4], neurological signs due to nerve compression, such as paraesthesia or sensory loss, as reported by our patient. However, this tumour can also be asymptomatic [1,3] with incidental discovery in 25 to 40% of cases [2]. The radiological features vary according to the stage of the tumour. Classically, conventional radiology shows a clearly demarcated filling defect of variable dimensions, suggesting a benign odontogenic tumour or cystic lesion [2]. However, large lipomas can be associated with thinning or sometimes even destruction of the cortex or periosteal reaction, resulting clinically in pain and swelling. Computed tomography demonstrates a fat-filled defect with negative densities, sometimes associated with calcifications with densities of 0 to 20 Hounsfield Units. MRI plays a major role in the diagnosis and is the most appropriate examination to characterize this tumour and eliminate certain differential diagnoses. MRI typically shows a lesion with a hypointense T1 signal, an intermediate T2 signal, and a hypointense signal on fat saturation sequences (STIR, T2 FAT-SAT). Calcifications, bony trabeculae and marginal osteosclerosis appear hypointense on all sequences. Several stages of intraosseous lipoma have been described on the basis of radio-histological correlations [2–4]. Stage 1: osteolytic image corresponding to a tumour composed of live adipocytes.
Please cite this article in press as: Touil H, et al. A rare mandibular tumour. European Annals of Otorhinolaryngology, Head and Neck diseases (2016), http://dx.doi.org/10.1016/j.anorl.2016.11.010
G Model ANORL-626; No. of Pages 4 4
ARTICLE IN PRESS H. Touil et al. / European Annals of Otorhinolaryngology, Head and Neck diseases xxx (2016) xxx–xxx
Stage 2: central calcification is observed within the osteolytic lesion with zones of fat necrosis due to focal ischaemia secondary to compression of capillaries. The associated peripheral osteosclerosis corresponds to a reaction of normal bone in contact with the tumour. Stage 3: ischaemic bone becomes more extensive, associated with images of reactive new bone formation. The differential diagnosis includes solitary bone cyst, classically observed in adolescents, and pseudocyst, which generally has less clearly defined margins. The other differential diagnoses include certain benign odontogenic tumours (myxoma), as well as bone infarction, fibrous dysplasia, osteoporosis and malignant odontogenic tumours, osteoblastoma, chondrosarcoma, or liposarcoma [4]. The fat density visible on the radiological assessment can guide the diagnosis, but the intraoperative findings and the macroscopic appearance are sometimes nonspecific [1,3]. The definitive diagnosis is based on histopathology [1,3–5], which confirms the presence of lamellar bone surrounding a central zone of adipose tissue [1] with no cellular atypias [2,4]. Histological proof is mandatory to exclude a malignant tumour. In the case reported here, inferior alveolar nerve decompression restored normal sensation. The diagnosis was only established on the basis of histopathological examination, showing adipose infiltration with rarefaction of bony trabeculae. Curative treatment is surgical [4] and is recommended in symptomatic forms [3]. A favourable course with resolution of the clinical features is generally observed [2].
Malignant transformation of mandibular intraosseous lipoma has not been reported in the literature [4]. 4. Conclusion Intraosseous lipoma must be considered in the differential diagnosis of benign tumours of the mandible. Certain malignant tumours must also be eliminated, especially in symptomatic patients. Histopathological examination is therefore required to establish the definitive diagnosis. Disclosure of interest The authors declare that they have no competing interest. References [1] Morais AL, Mendonc¸a EF, Gonc¸alves de Alencar AH, Estrela C. Intraosseous lipoma in the periapical region of a maxillary third molar. J Endod 2011;37: 554–7. [2] Aumar DK, Dadjo YB, Chagar B. Intraosseous lipoma of the calcaneus: report of a case and review of the literature. J Foot Ankle Surg 2013;52:360–3. [3] Bonnin Vilaplana M, Simón Adiego C, Molins López-Rodó L. Intraosseous lipoma of rib. Arch Bronconeumol 2005;41:236–7. [4] Shaini B, Jerly A, Shameena PM, Balan A. Intraosseous lipoma of mandible presenting as a swelling. J Oral Maxillofac Pathol 2013;17:126–8. [5] Zhu B, Liu XG, Liu ZJ, Liao HI, Jiang L, Wei F. Intraosseous lipoma of adjacent upper cervical vertebral bodies with significant paravertebral expansion. Chin Med J 2010;123:3160–2.
Please cite this article in press as: Touil H, et al. A rare mandibular tumour. European Annals of Otorhinolaryngology, Head and Neck diseases (2016), http://dx.doi.org/10.1016/j.anorl.2016.11.010