- Email: [email protected]
Unicystic ameloblastoma in an infant: A management dilemma
Journal of Cranio-Maxillo-Facial Surgery 41 (2013) e226ee230
Contents lists available at SciVerse ScienceDirect
Journal of Cranio-Maxillo-Facial Surgery journal homepage: www.jcmfs.com
Case report
Unicystic ameloblastoma in an infant: A management dilemma Ariel Israel Hirschhorn a, *, Marilena Vered b, c, Amos Buchner a, b, Gahl Greenberg d, Ran Yahalom a a
Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. Shlomo Taicher), The Chaim Sheba Medical Center, Tel Hashomer, Israel Department of Oral Pathology and Oral Medicine (Head: Prof. Marilena Vered), School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel c The Institute of Pathology, The Chaim Sheba Medical Center, Tel Hashomer, Israel d Department of Diagnostic Imaging (Head: Prof. Dr. Eli Konen), The Chaim Sheba Medical Center, Tel Hashomer, Israel b
a r t i c l e i n f o
a b s t r a c t
Article history: Paper received 8 October 2012 Accepted 10 January 2013
The authors describe the conservative management of a rare case of unicystic ameloblastoma (mural subtype) in a 10-month-old girl, the youngest patient reported thus far in the literature. Rather than subject the infant to further surgery, it was decided to monitor her closely and perform an additional operation in the event of recurrence, thus enabling uninterrupted mandibular growth and tooth development. The patient is now 3.5 years old and periodic follow-up is ongoing, with no evidence of recurrence. Ó 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.
Keywords: Unicystic ameloblastoma Odontogenic tumours Infants and children Management
1. Introduction A unicystic ameloblastoma (UAM) is a variant of ameloblastoma presenting as a cystic lesion that commonly occurs during the second decade of life. Clinically, it manifests as a swelling of the jaw, with a marked predilection for the mandible, especially the posterior region (Gardner et al., 2005). Three subtypes of UAM have been defined histologically: luminal, intraluminal and mural. The first two subtypes are usually treated by enucleation, while the third requires more extensive surgery. Although the individual patient’s age is not mentioned in the literature in most reported series of UAM cases, the youngest patient identified in the Englishlanguage literature thus far has been a 4-year-old girl (Keszler and Dominguez, 1986). The aim of this report is to describe the management of a rare case UAM in a 10-month-old girl, to analyze the literature on paediatric cases of UAM, and to propose treatment modalities for this age group. 2. Case report A 10-month-old girl was evaluated for a right facial swelling that was noticed by her parents after an accidental fall. The swelling did
* Corresponding author. Tel.: þ972 35303819; fax: þ972 35343432. E-mail addresses: [email protected], ariel.hirschorn_77@ hotmail.com (A.I. Hirschhorn).
not resolve and the parents reported that it had rapidly increased in size. There was no difficulty with feeding and the girl was otherwise healthy. Extra-oral examination revealed a swelling of the right cheek with considerable facial asymmetry. Intra-oral examination revealed a swelling in the right body of the mandible. The swelling had a rubbery consistency on all surfaces except for the buccal vestibular aspect where it was softer and had a bluish tinge. There was no significant tenderness on palpation and nor signs of inflammation. A magnetic resonance imaging (MRI) study was selected from among the available imaging modalities, first in order to minimize exposure of the infant to ionizing radiation, and second better to assess the soft tissue component and the extent of bony infiltration. A multiplanar multisequence MR scan of the mandible and the face was carried out under general anaesthesia, including T1- and T2weighted fat-saturated images before and after contrast administration. The scan revealed an expansile oval compound mass originating from the right mandible (Fig. 1a). It appeared to be growing in both medial and lateral directions, but causing mainly buccal expansion (Fig. 1b). The lesion had well-defined borders and measured approximately 3.0 3.0 3.5 cm. It showed a mixed cystic and solid consistency, with a dominant fluid component and an enhancing intramural solid element on the medial aspect, with a well-delineated surrounding capsule (Fig. 1c and d). The lesion appeared to be causing smooth expansion and thinning of the cortices, with evidence of pressure erosion on the remaining alveolar bone, but no signs of oedema nor infiltration into the adjacent soft tissues. There were no hemorrhagic products nor fluid levels within the lesion, nor were there any flow voids within the
1010-5182/$ e see front matter Ó 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jcms.2013.01.023
A.I. Hirschhorn et al. / Journal of Cranio-Maxillo-Facial Surgery 41 (2013) e226ee230
e227
Fig. 1. (a) Coronal fat-saturated T2-weighted scan shows a complex expansile mass of the right mandible with a dominant cystic component and an evident intramural mass arising from the medial wall. (b) Proton density image depicting the bucco-lingual expansion in the axial plane. Also noted is the smooth nature of the outer margins of the mass and the intra-lesional component on the medial aspect. (c) Coronal and (d) axial T1-weighted post-gadolinium fat-saturated images clearly showing the enhancing heterogenic mural mass and surrounding capsule.
mass. The rest of the mandible was unremarkable. There were tooth buds appropriate for the patient’s age. Given the clear-cut MRI findings of an encapsulated, predominantly cystic lesion that essentially ruled out the likelihood of malignancy, the surgeons decided to opt for a conservative surgical approach. Under general anaesthesia, a mucoperiosteal flap was raised via a vestibular approach, revealing a well-defined cystic lesion. Subperiosteal dissection was carried out and the lesion was completely enucleated. A yellowish cloudy fluid oozed from cystic lumen. Erosion of the inferior aspect of the mandible was noted during the procedure. Macroscopically, the form of the lesion was that of a collapsed cystic sac. The inner aspect of the cyst had an irregular surface. There was also a focal area of thickening in the wall of the cyst. Microscopically, the lesion was mainly cystic (Fig. 2a). The lumen was lined by non-keratinizing stratified squamous epithelium of a regular width for the most part and showed no rete-ridge formation. In some regions, the basal layer had a palisading appearance with subtle reverse polarity, and the suprabasal layers had a stellate reticulum-like (almost acantholytic) appearance (Fig. 2b).
In addition, the lining epithelium was hyperplastic and formed occasional papillary projections into the lumen (Fig. 2c). There were also areas in which the lining epithelium grew into the connective tissue wall and formed solid islands and nests (Fig. 3a). The epithelial cells in those solid areas were more densely packed and had aneosinophilic-to-amphophilic cytoplasm with indistinguishable intercellular borders. The nuclei were either vacuolated or hyperchromatic or pleomorphic (Fig. 3b). Occasional mitotic figures were also noted (Fig. 3c). The epithelial-connective tissue interface was occasionally hyalinized. The overall morphological and cytological findings were compatible with a diagnosis of UAM (mural subtype) with atypical cytological features. The patient was released from hospital on the 5th postoperative day and she was routinely followed-up. A decrease in the swelling of the right buccal space was noted at the 2-month postoperative visit. A follow-up MRI scan performed 13 months after surgery (Fig. 4aec) did not reveal any residual cystic component, and showed only focal oedematous changes and enhancement in the surgical bed, which could be attributed to the surgical intervention. The patient is now 3.5 years old and periodic follow-up is ongoing.
e228
A.I. Hirschhorn et al. / Journal of Cranio-Maxillo-Facial Surgery 41 (2013) e226ee230
Fig. 2. (a) Microscopically the lesion is lined by non-keratinized, stratified squamous epithelium of a regular width in the predominantly cystic area. (b) The basal layer is reminiscent of a palisading arrangement, and the overlying oedematous (almost acantholytic) epithelial layers appear similar to the stellate reticulum. (c) Papillary intraluminal projections are occasionally present (a and c 4 original magnification, b 10 original magnification).
Fig. 3. (a) Solid epithelial areas consisting of proliferation of the lining epithelium into the connective tissue wall. (b) The nuclei show hyperchromatism and occasional pleomorphism in the solid areas. (c) Occasional mitotic figures are observed (arrow) (a 4 original magnification, b 10 original magnification, c 20 original magnification).
3. Discussion The present case is unusual due to the very young age of the patient at diagnosis of a unicystic ameloblastoma (10 months). The
youngest patient reported thus far in the literature was a 4-year-old girl (Keszler and Dominguez, 1986). Treating infants and children for odontogenic lesions in the jawbones poses difficult management dilemmas for the surgeon (Butt et al., 2012). Surgical
A.I. Hirschhorn et al. / Journal of Cranio-Maxillo-Facial Surgery 41 (2013) e226ee230
e229
Fig. 4. Follow-up MRI scans of the mandible 13 months after the operation (a) coronal T1-weighted post-gadolinium fat-saturated and (b) T2-weighted fat-saturated coronal views. The cystic compound mass was removed, leaving residual oedema and enhancement at the surgical bed compatible with postoperative changes. (c) Axial T2-weighted fat-saturated image at the level of the mandible showing only focal oedematous changes at the surgical site.
management of intraosseous benign odontogenic lesions in children is generally complicated by a number of factors; the most important ones being the concern to minimize morbidity, to permit jaw function and to enable uninterrupted facial growth and tooth development. Another factor is the different bone physiology in children that is characterized by a higher percentage of cancellous bone, increased bone turnover and a reactive periosteum, which might permit the lesion to grow more rapidly and cause more extensive destruction of the jawbone, thus making surgery even more difficult (Keszler and Dominguez, 1986). The management chosen for the present case was not based on an incisional biopsy since additional and undesirable general anaesthesia of an infant would have been required. The findings of the MRI, which clearly indicated the presence of an encapsulated, predominantly cystic lesion, essentially ruled out the likelihood of malignancy, and this consideration supported the surgeons’ decision to perform a conservative surgical procedure consisting of a complete enucleation of the lesion. The surgical approach to a UAM is usually dependent upon the histopathological subtype of the tumour. Luminal and intraluminal subtypes are treated by a conservative method of enucleation or curettage, while the mural subtype is usually treated more aggressively, particularly in cases in which there is considerable proliferation of tumour islands close to the surrounding cancellous bone. In these latter cases, many authors have suggested approaching the lesion as a solid/multicystic ameloblastoma (Robinson and Martinez, 1977; Huang et al., 2007; Zhang et al., 2010). Some studies have shown that the recurrence rate of mural subtype UAM after conservative surgical treatment ranged from 10% to 43% (Lee et al., 2004). Recurrences have been observed
mainly after 4 years and may occur after 20 years (Ghandhi et al., 2006) and even 35 years (Eckardt et al., 2009). These data suggest that the mural subtype is a tumour of an unpredictable biologic behaviour, and so the postoperative histopathological diagnosis of a mural subtype UAM in our patient further complicated the dilemma of how to manage such a young child. The final diagnosis of a mural subtype UAM can be made only after surgery and after the thorough histopathologic examination of the entire specimen. The dilemma was whether to subject the infant to an immediate additional and more aggressive surgical treatment or to follow her closely with serial radiographs and clinical examinations. The decision was made that a second surgical intervention would be performed only if and when there was convincing evidence of recurrence. In the meantime, mandibular function and tooth development would remain uninterrupted. It should be borne in mind that the mandible has the most delayed growth of all the facial bones and that most of its growth occurs after birth. Furthermore, unlike the craniofacial skeletal unit whose growth is least determined by extrinsic forces, the growth of the mandible is highly dependent on postnatal functional demands that are placed on it (Spalding, 2004). A search of the literature for more specific recommendations for the treatment of infant patients with UAM revealed many difficulties in interpreting the available data, mainly due to the following reasons: a. Many studies on UAM include patients of all ages (paediatric to elderly) without differentiating between the recommendations for treatment modalities according to age groups (Ghandhi et al., 2006).
e230
A.I. Hirschhorn et al. / Journal of Cranio-Maxillo-Facial Surgery 41 (2013) e226ee230
b. There are studies in which therapeutic options for UAM are not differentiated according to the various histopathological subtypes (Huang et al., 2007; Zhang et al., 2010). c. UAM is a relatively uncommon tumour and treatment options are usually based on single case reports or limited series in the relevant literature. d. Several surgical approaches for UAM are described in the literature, among them marsupialization followed by conservative surgical enucleation alone (Zhang et al., 2010). Enucleation and physiochemical curettage (Ord et al., 2002) and resection (marginal/segmental/en bloc) (Ord et al., 2002; Ghandhi et al., 2006). Since these studies are mostly small series of cases, no firm or specific conclusions could be reached on treatment outcomes. The conclusion of this search is that the current literature lacks studies on adequately large groups of paediatric patients and none on infants diagnosed as having UAM of a known histopathological subtype who were treated by a unified approach and followed-up for an adequate period of time. The dilemma of whether to perform an immediate second and more aggressive surgery or to closely follow-up an infant has been discussed in only a few papers dealing with UAM in children. Escande et al. (2009) stated that conservative treatment is reasonable for patients in their first decade. Zhang et al. (2010) recommended conservative treatment at initial presentation of a UAM, reserving a more aggressive therapy in the event of a recurrence. Lee et al. (2004) advocated against further aggressive surgery after receiving a histopathological diagnosis of UAM due to the inevitable morbidity. Takahashi et al. (1998) stated that conservative treatment is an acceptable initial treatment of ameloblastoma in children who can be followed-up in a precise, detailed manner. 4. Conclusion In spite of expectations of a considerable recurrence rate in the mural subtype UAM, we join the others in the sparse literature in advocating that children, especially infants, should first be treated conservatively, reserving a more aggressive surgical approach in the event of recurrence This protocol mandates a very close followup period of at least 5 years, and preferably up to 20 years, for detecting the earliest signs of recurrence, whereupon further intervention is mandated.
Ethical approval None required. Funding None. Competing interests None declared. Acknowledgements The authors would like to Prof. James Scuibba for his contribution to the histopathological diagnosis, and Ms. Esther Eshkol for editorial assistance. References Butt FM, Guthua SW, Awange DA, Dimba EA, Macigo FG: The pattern and occurrence of ameloblastoma in adolescents treated at a university teaching hospital, in Kenya: a 13-year study. J Craniomaxillofac Surg 40: e39ee45, 2012 Eckardt AM, Kokemüller H, Flemming P, Schultze A: Recurrent ameloblastoma following osseous reconstruction e a review of twenty years. J Craniomaxillofac Surg 37: 36e41, 2009 Escande C, Chaine A, Menard P, Ernenwein D, Ghoul S, Bouattour A, et al: A treatment algorithm for adult ameloblastomas according to the Pitié-Salpêtrière Hospital experience. J Craniomaxillofac Surg 37: 363e369, 2009 Gardner DG, Heikinheino K, Shear M, Philipsen HP, Coleman H: Ameloblastoma. In: Barnes L, Eveson JW, Reichart P, Sidransky D (eds), World health organization classification of tumours. Pathology and genetics head and neck tumors. Lyon: IARC Press, 300, 2005 Ghandhi D, Ayoub AF, Pogrel MA, MacDonald G, Brocklebank LM, Moos KF: Ameloblastoma: a surgeon’s dilemma. J Oral Maxillofac Surg 64: 1010e1014, 2006 Huang IY, Lai ST, Chen CH, Chen CM, Wu CW, Shen YH: Surgical management of ameloblastoma in children. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 104: 478e485, 2007 Keszler A, Dominguez FV: Ameloblastoma in childhood. J Oral Maxillofac Surg 44: 609e613, 1986 Lee PK, Samman N, Ng IO: Unicystic ameloblastoma e use of Carnoy’s solution after enucleation. Int J Oral Maxillofac Surg 33: 263e267, 2004 Ord RA, Blanchaert RH, Nikitakis NG, Sauk JJ: Ameloblastoma in children. J Oral Maxillofac Surg 60: 762e770, 2002 Robinson L, Martinez MG: Unicystic ameloblastoma a prognostically distinct entity. Cancer 40: 2278e2285, 1977 Spalding PM: Craniofacial growth and development: current understanding and clinical considerations. In: Miloro M (ed.), Peterson’s principles of oral and maxillofacial surgery. London: BC Decker, 1051, 2004 Takahashi K, Miyauchi K, Sato K: Treatment of ameloblastoma in children. Br J Oral Maxillofac Surg 36: 453e456, 1998 Zhang J, Gu Z, Jiang L, Zhao J, Tian M, Zhou J, et al: Ameloblastoma in children and adolescents. Br J Oral Maxillofac Surg 48: 549e554, 2010
Contents lists available at SciVerse ScienceDirect
Journal of Cranio-Maxillo-Facial Surgery journal homepage: www.jcmfs.com
Case report
Unicystic ameloblastoma in an infant: A management dilemma Ariel Israel Hirschhorn a, *, Marilena Vered b, c, Amos Buchner a, b, Gahl Greenberg d, Ran Yahalom a a
Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. Shlomo Taicher), The Chaim Sheba Medical Center, Tel Hashomer, Israel Department of Oral Pathology and Oral Medicine (Head: Prof. Marilena Vered), School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel c The Institute of Pathology, The Chaim Sheba Medical Center, Tel Hashomer, Israel d Department of Diagnostic Imaging (Head: Prof. Dr. Eli Konen), The Chaim Sheba Medical Center, Tel Hashomer, Israel b
a r t i c l e i n f o
a b s t r a c t
Article history: Paper received 8 October 2012 Accepted 10 January 2013
The authors describe the conservative management of a rare case of unicystic ameloblastoma (mural subtype) in a 10-month-old girl, the youngest patient reported thus far in the literature. Rather than subject the infant to further surgery, it was decided to monitor her closely and perform an additional operation in the event of recurrence, thus enabling uninterrupted mandibular growth and tooth development. The patient is now 3.5 years old and periodic follow-up is ongoing, with no evidence of recurrence. Ó 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.
Keywords: Unicystic ameloblastoma Odontogenic tumours Infants and children Management
1. Introduction A unicystic ameloblastoma (UAM) is a variant of ameloblastoma presenting as a cystic lesion that commonly occurs during the second decade of life. Clinically, it manifests as a swelling of the jaw, with a marked predilection for the mandible, especially the posterior region (Gardner et al., 2005). Three subtypes of UAM have been defined histologically: luminal, intraluminal and mural. The first two subtypes are usually treated by enucleation, while the third requires more extensive surgery. Although the individual patient’s age is not mentioned in the literature in most reported series of UAM cases, the youngest patient identified in the Englishlanguage literature thus far has been a 4-year-old girl (Keszler and Dominguez, 1986). The aim of this report is to describe the management of a rare case UAM in a 10-month-old girl, to analyze the literature on paediatric cases of UAM, and to propose treatment modalities for this age group. 2. Case report A 10-month-old girl was evaluated for a right facial swelling that was noticed by her parents after an accidental fall. The swelling did
* Corresponding author. Tel.: þ972 35303819; fax: þ972 35343432. E-mail addresses: [email protected], ariel.hirschorn_77@ hotmail.com (A.I. Hirschhorn).
not resolve and the parents reported that it had rapidly increased in size. There was no difficulty with feeding and the girl was otherwise healthy. Extra-oral examination revealed a swelling of the right cheek with considerable facial asymmetry. Intra-oral examination revealed a swelling in the right body of the mandible. The swelling had a rubbery consistency on all surfaces except for the buccal vestibular aspect where it was softer and had a bluish tinge. There was no significant tenderness on palpation and nor signs of inflammation. A magnetic resonance imaging (MRI) study was selected from among the available imaging modalities, first in order to minimize exposure of the infant to ionizing radiation, and second better to assess the soft tissue component and the extent of bony infiltration. A multiplanar multisequence MR scan of the mandible and the face was carried out under general anaesthesia, including T1- and T2weighted fat-saturated images before and after contrast administration. The scan revealed an expansile oval compound mass originating from the right mandible (Fig. 1a). It appeared to be growing in both medial and lateral directions, but causing mainly buccal expansion (Fig. 1b). The lesion had well-defined borders and measured approximately 3.0 3.0 3.5 cm. It showed a mixed cystic and solid consistency, with a dominant fluid component and an enhancing intramural solid element on the medial aspect, with a well-delineated surrounding capsule (Fig. 1c and d). The lesion appeared to be causing smooth expansion and thinning of the cortices, with evidence of pressure erosion on the remaining alveolar bone, but no signs of oedema nor infiltration into the adjacent soft tissues. There were no hemorrhagic products nor fluid levels within the lesion, nor were there any flow voids within the
1010-5182/$ e see front matter Ó 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jcms.2013.01.023
A.I. Hirschhorn et al. / Journal of Cranio-Maxillo-Facial Surgery 41 (2013) e226ee230
e227
Fig. 1. (a) Coronal fat-saturated T2-weighted scan shows a complex expansile mass of the right mandible with a dominant cystic component and an evident intramural mass arising from the medial wall. (b) Proton density image depicting the bucco-lingual expansion in the axial plane. Also noted is the smooth nature of the outer margins of the mass and the intra-lesional component on the medial aspect. (c) Coronal and (d) axial T1-weighted post-gadolinium fat-saturated images clearly showing the enhancing heterogenic mural mass and surrounding capsule.
mass. The rest of the mandible was unremarkable. There were tooth buds appropriate for the patient’s age. Given the clear-cut MRI findings of an encapsulated, predominantly cystic lesion that essentially ruled out the likelihood of malignancy, the surgeons decided to opt for a conservative surgical approach. Under general anaesthesia, a mucoperiosteal flap was raised via a vestibular approach, revealing a well-defined cystic lesion. Subperiosteal dissection was carried out and the lesion was completely enucleated. A yellowish cloudy fluid oozed from cystic lumen. Erosion of the inferior aspect of the mandible was noted during the procedure. Macroscopically, the form of the lesion was that of a collapsed cystic sac. The inner aspect of the cyst had an irregular surface. There was also a focal area of thickening in the wall of the cyst. Microscopically, the lesion was mainly cystic (Fig. 2a). The lumen was lined by non-keratinizing stratified squamous epithelium of a regular width for the most part and showed no rete-ridge formation. In some regions, the basal layer had a palisading appearance with subtle reverse polarity, and the suprabasal layers had a stellate reticulum-like (almost acantholytic) appearance (Fig. 2b).
In addition, the lining epithelium was hyperplastic and formed occasional papillary projections into the lumen (Fig. 2c). There were also areas in which the lining epithelium grew into the connective tissue wall and formed solid islands and nests (Fig. 3a). The epithelial cells in those solid areas were more densely packed and had aneosinophilic-to-amphophilic cytoplasm with indistinguishable intercellular borders. The nuclei were either vacuolated or hyperchromatic or pleomorphic (Fig. 3b). Occasional mitotic figures were also noted (Fig. 3c). The epithelial-connective tissue interface was occasionally hyalinized. The overall morphological and cytological findings were compatible with a diagnosis of UAM (mural subtype) with atypical cytological features. The patient was released from hospital on the 5th postoperative day and she was routinely followed-up. A decrease in the swelling of the right buccal space was noted at the 2-month postoperative visit. A follow-up MRI scan performed 13 months after surgery (Fig. 4aec) did not reveal any residual cystic component, and showed only focal oedematous changes and enhancement in the surgical bed, which could be attributed to the surgical intervention. The patient is now 3.5 years old and periodic follow-up is ongoing.
e228
A.I. Hirschhorn et al. / Journal of Cranio-Maxillo-Facial Surgery 41 (2013) e226ee230
Fig. 2. (a) Microscopically the lesion is lined by non-keratinized, stratified squamous epithelium of a regular width in the predominantly cystic area. (b) The basal layer is reminiscent of a palisading arrangement, and the overlying oedematous (almost acantholytic) epithelial layers appear similar to the stellate reticulum. (c) Papillary intraluminal projections are occasionally present (a and c 4 original magnification, b 10 original magnification).
Fig. 3. (a) Solid epithelial areas consisting of proliferation of the lining epithelium into the connective tissue wall. (b) The nuclei show hyperchromatism and occasional pleomorphism in the solid areas. (c) Occasional mitotic figures are observed (arrow) (a 4 original magnification, b 10 original magnification, c 20 original magnification).
3. Discussion The present case is unusual due to the very young age of the patient at diagnosis of a unicystic ameloblastoma (10 months). The
youngest patient reported thus far in the literature was a 4-year-old girl (Keszler and Dominguez, 1986). Treating infants and children for odontogenic lesions in the jawbones poses difficult management dilemmas for the surgeon (Butt et al., 2012). Surgical
A.I. Hirschhorn et al. / Journal of Cranio-Maxillo-Facial Surgery 41 (2013) e226ee230
e229
Fig. 4. Follow-up MRI scans of the mandible 13 months after the operation (a) coronal T1-weighted post-gadolinium fat-saturated and (b) T2-weighted fat-saturated coronal views. The cystic compound mass was removed, leaving residual oedema and enhancement at the surgical bed compatible with postoperative changes. (c) Axial T2-weighted fat-saturated image at the level of the mandible showing only focal oedematous changes at the surgical site.
management of intraosseous benign odontogenic lesions in children is generally complicated by a number of factors; the most important ones being the concern to minimize morbidity, to permit jaw function and to enable uninterrupted facial growth and tooth development. Another factor is the different bone physiology in children that is characterized by a higher percentage of cancellous bone, increased bone turnover and a reactive periosteum, which might permit the lesion to grow more rapidly and cause more extensive destruction of the jawbone, thus making surgery even more difficult (Keszler and Dominguez, 1986). The management chosen for the present case was not based on an incisional biopsy since additional and undesirable general anaesthesia of an infant would have been required. The findings of the MRI, which clearly indicated the presence of an encapsulated, predominantly cystic lesion, essentially ruled out the likelihood of malignancy, and this consideration supported the surgeons’ decision to perform a conservative surgical procedure consisting of a complete enucleation of the lesion. The surgical approach to a UAM is usually dependent upon the histopathological subtype of the tumour. Luminal and intraluminal subtypes are treated by a conservative method of enucleation or curettage, while the mural subtype is usually treated more aggressively, particularly in cases in which there is considerable proliferation of tumour islands close to the surrounding cancellous bone. In these latter cases, many authors have suggested approaching the lesion as a solid/multicystic ameloblastoma (Robinson and Martinez, 1977; Huang et al., 2007; Zhang et al., 2010). Some studies have shown that the recurrence rate of mural subtype UAM after conservative surgical treatment ranged from 10% to 43% (Lee et al., 2004). Recurrences have been observed
mainly after 4 years and may occur after 20 years (Ghandhi et al., 2006) and even 35 years (Eckardt et al., 2009). These data suggest that the mural subtype is a tumour of an unpredictable biologic behaviour, and so the postoperative histopathological diagnosis of a mural subtype UAM in our patient further complicated the dilemma of how to manage such a young child. The final diagnosis of a mural subtype UAM can be made only after surgery and after the thorough histopathologic examination of the entire specimen. The dilemma was whether to subject the infant to an immediate additional and more aggressive surgical treatment or to follow her closely with serial radiographs and clinical examinations. The decision was made that a second surgical intervention would be performed only if and when there was convincing evidence of recurrence. In the meantime, mandibular function and tooth development would remain uninterrupted. It should be borne in mind that the mandible has the most delayed growth of all the facial bones and that most of its growth occurs after birth. Furthermore, unlike the craniofacial skeletal unit whose growth is least determined by extrinsic forces, the growth of the mandible is highly dependent on postnatal functional demands that are placed on it (Spalding, 2004). A search of the literature for more specific recommendations for the treatment of infant patients with UAM revealed many difficulties in interpreting the available data, mainly due to the following reasons: a. Many studies on UAM include patients of all ages (paediatric to elderly) without differentiating between the recommendations for treatment modalities according to age groups (Ghandhi et al., 2006).
e230
A.I. Hirschhorn et al. / Journal of Cranio-Maxillo-Facial Surgery 41 (2013) e226ee230
b. There are studies in which therapeutic options for UAM are not differentiated according to the various histopathological subtypes (Huang et al., 2007; Zhang et al., 2010). c. UAM is a relatively uncommon tumour and treatment options are usually based on single case reports or limited series in the relevant literature. d. Several surgical approaches for UAM are described in the literature, among them marsupialization followed by conservative surgical enucleation alone (Zhang et al., 2010). Enucleation and physiochemical curettage (Ord et al., 2002) and resection (marginal/segmental/en bloc) (Ord et al., 2002; Ghandhi et al., 2006). Since these studies are mostly small series of cases, no firm or specific conclusions could be reached on treatment outcomes. The conclusion of this search is that the current literature lacks studies on adequately large groups of paediatric patients and none on infants diagnosed as having UAM of a known histopathological subtype who were treated by a unified approach and followed-up for an adequate period of time. The dilemma of whether to perform an immediate second and more aggressive surgery or to closely follow-up an infant has been discussed in only a few papers dealing with UAM in children. Escande et al. (2009) stated that conservative treatment is reasonable for patients in their first decade. Zhang et al. (2010) recommended conservative treatment at initial presentation of a UAM, reserving a more aggressive therapy in the event of a recurrence. Lee et al. (2004) advocated against further aggressive surgery after receiving a histopathological diagnosis of UAM due to the inevitable morbidity. Takahashi et al. (1998) stated that conservative treatment is an acceptable initial treatment of ameloblastoma in children who can be followed-up in a precise, detailed manner. 4. Conclusion In spite of expectations of a considerable recurrence rate in the mural subtype UAM, we join the others in the sparse literature in advocating that children, especially infants, should first be treated conservatively, reserving a more aggressive surgical approach in the event of recurrence This protocol mandates a very close followup period of at least 5 years, and preferably up to 20 years, for detecting the earliest signs of recurrence, whereupon further intervention is mandated.
Ethical approval None required. Funding None. Competing interests None declared. Acknowledgements The authors would like to Prof. James Scuibba for his contribution to the histopathological diagnosis, and Ms. Esther Eshkol for editorial assistance. References Butt FM, Guthua SW, Awange DA, Dimba EA, Macigo FG: The pattern and occurrence of ameloblastoma in adolescents treated at a university teaching hospital, in Kenya: a 13-year study. J Craniomaxillofac Surg 40: e39ee45, 2012 Eckardt AM, Kokemüller H, Flemming P, Schultze A: Recurrent ameloblastoma following osseous reconstruction e a review of twenty years. J Craniomaxillofac Surg 37: 36e41, 2009 Escande C, Chaine A, Menard P, Ernenwein D, Ghoul S, Bouattour A, et al: A treatment algorithm for adult ameloblastomas according to the Pitié-Salpêtrière Hospital experience. J Craniomaxillofac Surg 37: 363e369, 2009 Gardner DG, Heikinheino K, Shear M, Philipsen HP, Coleman H: Ameloblastoma. In: Barnes L, Eveson JW, Reichart P, Sidransky D (eds), World health organization classification of tumours. Pathology and genetics head and neck tumors. Lyon: IARC Press, 300, 2005 Ghandhi D, Ayoub AF, Pogrel MA, MacDonald G, Brocklebank LM, Moos KF: Ameloblastoma: a surgeon’s dilemma. J Oral Maxillofac Surg 64: 1010e1014, 2006 Huang IY, Lai ST, Chen CH, Chen CM, Wu CW, Shen YH: Surgical management of ameloblastoma in children. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 104: 478e485, 2007 Keszler A, Dominguez FV: Ameloblastoma in childhood. J Oral Maxillofac Surg 44: 609e613, 1986 Lee PK, Samman N, Ng IO: Unicystic ameloblastoma e use of Carnoy’s solution after enucleation. Int J Oral Maxillofac Surg 33: 263e267, 2004 Ord RA, Blanchaert RH, Nikitakis NG, Sauk JJ: Ameloblastoma in children. J Oral Maxillofac Surg 60: 762e770, 2002 Robinson L, Martinez MG: Unicystic ameloblastoma a prognostically distinct entity. Cancer 40: 2278e2285, 1977 Spalding PM: Craniofacial growth and development: current understanding and clinical considerations. In: Miloro M (ed.), Peterson’s principles of oral and maxillofacial surgery. London: BC Decker, 1051, 2004 Takahashi K, Miyauchi K, Sato K: Treatment of ameloblastoma in children. Br J Oral Maxillofac Surg 36: 453e456, 1998 Zhang J, Gu Z, Jiang L, Zhao J, Tian M, Zhou J, et al: Ameloblastoma in children and adolescents. Br J Oral Maxillofac Surg 48: 549e554, 2010