Hybrid variant of desmoplastic ameloblastoma, a rare histomorphological entity – A case report and review of literature

Hybrid variant of desmoplastic ameloblastoma, a rare histomorphological entity – A case report and review of literature

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ARTICLE IN PRESS Journal of Oral and Maxillofacial Surgery, Medicine, and Pathology xxx (2015) xxx–xxx

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Case Report

Hybrid variant of desmoplastic ameloblastoma, a rare histomorphological entity – A case report and review of literature Sramana Mukhopadhyay a,∗ , Cecil T. Thomas b , Kavitha Bali a , Santosh Koshy c , Pranay Gaikwad b a

Department of General Pathology, Christian Medical College, Vellore, India Department of General Surgery Unit 1 – Head and Neck Oncosurgery, Christian Medical College, Vellore, India c Department of Dental and Oral Surgery, Christian Medical College, Vellore, India b

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Article history: Received 2 April 2015 Received in revised form 3 May 2015 Accepted 12 May 2015 Available online xxx Keywords: Desmoplastic Hybrid Mandible Plexiform

a b s t r a c t Desmoplastic ameloblastoma is an uncommon variant of ameloblastoma with special anatomic distribution, histomorphology and radiographic features that differ from those of conventional ameloblastoma. The “Hybrid” variant of desmoplastic ameloblastoma is a rare variant in which histologically, a follicular or plexiform pattern of conventional ameloblastoma coexists with areas of desmoplastic ameloblastoma. We report an unusual case of such a hybrid lesion presenting as a left hemi-mandibular swelling in a 41year-old female patient. The purpose of this article is to add to the existing body of literature a rarely reported condition. © 2015 Asian AOMS, ASOMP, JSOP, JSOMS, JSOM, and JAMI. Published by Elsevier Ltd. All rights reserved.夽

1. Introduction Ameloblastoma is a benign neoplasm of odontogenic epithelial origin. It arises from the remnants of the dental lamina, the enamel organ of the developing tooth, the epithelial lining of odontogenic cysts or the basal cells of the oral mucosa [1]. It is a slowly growing, locally invasive benign tumor with a high propensity for local recurrence. Vickers and Gorlin in 1970 defined the histopathological features of ameloblastoma. These features include hyperchromasia, palisading and reverse polarization of the basal nuclei of the epithelial cells with vacuolization of the cytoplasm [2]. Histological types include: follicular, plexiform, acanthomatous and the desmoplastic. Desmoplastic ameloblastoma (DA) often occurs in the anterior region of jaws with unique radiographic appearance resembling fibrosseous lesions and shows distinct histopathology characterized by extensive stromal collagenization or desmoplasia surrounding compressed islands of odontogenic epithelium. A transitional form of desmoplastic ameloblastoma, showing microscopic

夽 Asian AOMS: Asian Association of Oral and Maxillofacial Surgeons; ASOMP: Asian Society of Oral and Maxillofacial Pathology; JSOP: Japanese Society of Oral Pathology; JSOMS: Japanese Society of Oral and Maxillofacial Surgeons; JSOM: Japanese Society of Oral Medicine; JAMI: Japanese Academy of Maxillofacial Implants. ∗ Corresponding author at: Department of General Pathology, Christian Medical College, Vellore, India. Tel.: +91 0416 228 2005. E-mail address: [email protected] (S. Mukhopadhyay).

features of desmoplastic variant together with areas of classical follicular/plexiform ameloblastoma, has been described as a “hybrid lesion” [3,4]. We describe a unique case of hybrid variant of desmoplastic ameloblastoma (HA) in a 41-year-old female with details of clinical, radiographic and unusual histologic features. A detailed review of literature revealed only a handful of reported cases since the first description of HA by Waldron and El-Mofty in 1987 [5] with no recurrence of the lesion in any of the reported cases. Here, we add an additional case of HA to the existing literature as the synchronized existence of desmoplastic ameloblastoma with plexiform ameloblastoma is a rare event and this is the first case to be reported from our institution. 2. Case report A 41-year-old female presented with swelling in the left hemimandible for the past 10 years with gradual increase in size. There was no associated pain, bleeding, discharge, or difficulty in chewing and swallowing. On examination, there was a 5 cm × 5 cm noncompressible, non-pulsatile, non-fluctuant and immobile swelling over the inferior aspect of the horizontal ramus of the left hemimandible extending to the gingiva. It was globular in shape, with a smooth surface, well defined margins and firm consistency. The skin over the swelling was normal. There were no ulcers or satellite lesions. A CT scan of the head and neck region showed a large

http://dx.doi.org/10.1016/j.ajoms.2015.05.003 2212-5558/© 2015 Asian AOMS, ASOMP, JSOP, JSOMS, JSOM, and JAMI. Published by Elsevier Ltd. All rights reserved.夽

Please cite this article in press as: Mukhopadhyay S, et al. Hybrid variant of desmoplastic ameloblastoma, a rare histomorphological entity – A case report and review of literature. J Oral Maxillofac Surg Med Pathol (2015), http://dx.doi.org/10.1016/j.ajoms.2015.05.003

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exophytic, expansile, lytic lesion involving most of the mandibular body on the left side extending into the vertical ramus with focal areas of cortical breach (Fig. 1). The biopsy from the lesion was reported as desmoplastic ameloblastoma. The patient was posted for wide local excision. Intraoperatively, multiple swellings were noted in the horizontal ramus with egg shell crackling for which extended segmental mandibulectomy with free fibular osteocutaneous flap reconstruction was done. On gross pathological examination, the surgical specimen showed multiple nodular swellings in the ramus of the mandible measuring 7 cm × 6 cm × 5 cm in toto with cystic and solid cut surface. The cystic area contained greenish-mucoid material while the solid area appeared homogeneously white (Fig. 2A). Histopathologically, the lesion demonstrated solid and cystic components. The solid areas of the tumor showed islands, nests and anastomosing strands of ameloblastic epithelium with central stellate reticulum and peripheral palisading of nuclei (Fig. 2B). Few of the islands showed central squamoid differentiation and edema with formation of microcysts. Also, there were irregular shaped epithelial islands, few displaying a swirled hypercellular center with spindle shaped to squamoid epithelial cells, absent peripheral palisading and surrounded by narrow zones of loosely structured connective tissue embedded in a desmoplastic stroma (Fig. 2C and D). There was focal infiltration of tumor into the cortical bone (Fig. 2E). There was no necrosis or significant mitotic activity. The cystic component showed a fibrous cyst wall lined by ameloblastic epithelium composed of columnar to cuboidal cells with hyperchromatic nuclei displaying reverse polarity and basilar cytoplasmic vacuolation (Fig. 2F). The overall features were suggestive of a hybrid form of desmoplastic ameloblastoma as both typical desmoplastic areas with plexiform areas were seen. 3. Discussion Desmoplastic ameloblastoma was first described by Tussole et al. in 1984 and reviewed by Waldron and El-Mofty in 1987 [5]. In 1992, the World Health Organisation (WHO) regarded

Fig. 1. A large exophytic, expansile, lytic lesion involving most of the mandible on the left side and extending into the ramus with focal areas of cortical breach and thin irregular internal septations.

it as a variant of ameloblastoma [4]. The striking difference in the anatomic location, mainly in the anterior premolar region of the maxilla/mandible, unusual radiologic presentation of mixed radiolucency-radioopacity with ill-defined borders and distinctive histopathology of extensive stromal desmoplasia with scattered odontogenic epithelium makes it a distinct clinicopathologic entity. “Hybrid” lesion of desmoplastic ameloblastoma and conventional ameloblastoma is an unusual variant of ameloblastoma, which was first described by Waldron and El-Mofty in 1987. Hybrid lesions show typical microscopic features of DA characterized by pronounced stromal desmoplasia together with areas of follicular, plexiform and acanthomatous ameloblastoma [4,5]. In the literature, it is noticed that the DA represented the least common odontogenic tumor. Among the 89 cases of ameloblastomas studied by Takata et al., 7.9% were diagnosed as DA and only 1.1% as “hybrid lesion” [10]. In Japan, the DA was only 5.3% of all the cases of intraosseous ameloblastomas diagnosed in 27 years [6,7]. As per an Indian study, ameloblastoma accounted for 1.18% of the total surgical specimens received over a period of 25 years with DA accounting for only 2.25% of the various histological variants of ameloblastoma. HA was not reported [8]. The present case is the first case of HA to be reported from our institution. The HA has an almost equal sex predilection and occurs in a wide age range of 17–82 years. Strikingly, it has been reported predominantly in the Asians with a definite mandibular predilection [6]. Not surprisingly, even the present case is a 41-year-old female patient with the lesion in the anterior ramus of the left hemi-mandible. The literature shows that most cases of HA present as mixed radiolucent and radiopaque lesions with irregular borders similar to the common radiological pattern observed in DA or fibro osseous lesions. A few cases of HA also present as multilocular radiolucencies similar to the common radiographic pattern of conventional ameloblastoma [9]. Takata et al. also believed that the mixed pattern expresses the infiltrative nature of the tumor. As the DA infiltrates the bone marrow spaces, remnants of the original non-metaplastic or non-neoplastic bone remain in the tumor tissue. The ill-defined borders may also be attributed to the infiltrative behavior of the tumor [4,10]. The present case showed an expansile, lytic lesion involving most of the mandibular body extending to the adjoining ramus with focal areas of cortical breach which was confirmed histologically. Microscopically, in the present case, the tumor showed abundant desmoplastic stroma and islands of ameloblastic epithelium together with plexiform areas displaying anastomosing strands of ameloblastic epithelium with central stellate reticulum and peripheral palisading of nuclei, as exactly described by Waldron and El-Mofty [5]. Histopathological interpretation of the coexistence of DA with the conventional variant in a “Hybrid” lesion remains challenging and is still unclear with one of the three possibilities – (a) the desmoplastic change occurs secondarily in the stroma of a pre-existing solid or multicystic ameloblastoma; (b) a part of primary desmoplastic ameloblastoma alters into the conventional ameloblastoma; or (c) the hybrid lesion being a type of collision tumor [4]. Mahadesh et al. reported the 5-year recurrence rate of 53% after the surgical treatment of ameloblastomas [11]. Desmoplastic ameloblastoma is more aggressive than its other variants. This is suggested by its potential to reach large size, an early invasion of adjacent structures, diffuse and ill-defined radiographic appearance and the histological presence of bone invasion [12]. However, the prognosis of hybrid lesions has not been clearly established. It is generally described that most cases of DA have ill-defined margins and may have a propensity to recur, at least as frequently as the conventional ameloblastomas. As the biological behavior, radiographic and histological features of the hybrid lesion are still not fully understood, the lesion still needs more extensive tumor analysis, follow-up and reporting into the medical literature.

Please cite this article in press as: Mukhopadhyay S, et al. Hybrid variant of desmoplastic ameloblastoma, a rare histomorphological entity – A case report and review of literature. J Oral Maxillofac Surg Med Pathol (2015), http://dx.doi.org/10.1016/j.ajoms.2015.05.003

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Fig. 2. (A) Solid component of the tumor involving the left ramus of the mandible. (B) Plexiform areas of the tumor with islands and anastomosing strands of ameloblastic epithelium with central stellate reticulum and peripheral palisading of nuclei. (C and D) Irregular epithelial islands, few displaying a swirled hypercellular center, absent peripheral palisading and embedded in a desmoplastic stroma. (E) Tumor infiltrating bone. (F) Cystic component of tumor lined by ameloblastic epithelium. (For interpretation of the references to color in the text, the reader is referred to the web version of the article.)

Conflict of interest None. References [1] Belardo E, Velasco I, Guerra A, Rosa E. Mandibular ameloblastoma in a 10year-old child: case report and review of the literature. Int J Odontostomatol 2012;6:331–6. [2] Shaikhi K, Neiders M, Chen F, Aguirre A. Morphological variants of ameloblastoma and their mimickers. N Am J Med Sci 2012;5:20–8. [3] Gupta A, Jindal C. Hybrid ameloblastoma: report of a rare case and review of literature. Int J Oral Maxillofac Pathol 2011;2:68–72. [4] Vardhan BGH, Ingle E, Dornadula K, Gopal S. Hybrid lesion of desmoplastic and conventional ameloblastoma – a case report. JIOH 2011;3. [5] Waldron CA, El-Mofty SK. A histopathologic study of 116 ameloblastomas with special reference to the desmoplastic variant. Oral Surg Oral Med Oral Pathol 1987;63:441–51. [6] Angadi PV, Kale A, Hallikerimath S, Kotrashetti V, Mane D, Bhatt P, et al. ‘Hybrid’ desmoplastic ameloblastoma: an unusual case report with

[7]

[8]

[9]

[10]

[11]

[12]

immunohistochemical investigation for TGF-␤ and review of literature. East J Med 2011;16:9–17. dos Santos JN, DeSouza VF, Azevêdo RA, Sarmento VA, Souza LB. “Hybrid” lesion of desmoplastic and conventional ameloblastoma: immunohistochemical aspects. Rev Bras Otorrinolaringol 2006;72:709–13. Chawla R, Ramalingam K, Sarkar A, Muddiah S. Ninety-one cases of ameloblastoma in an Indian population: a comprehensive review. J Nat Sci Biol Med 2013;4:310–5. Effiom OA, James O, Akeju OT, Salami AS, Odukoya O. Hybrid ameloblastoma in a Nigerian: report of a case and review of literature. Open J Stomatol 2013;3:347–53. Takata T, Miyauchi M, Ito H, Ogawa I, Kudo Y, Zhao M, et al. Clinical and histopathological analyses of desmoplastic ameloblastoma. Pathol Res Pract 1999;195:669–75. Mahadesh J, Rayapati DK, Maligi PM, Ramachandra P. Unicystic ameloblastoma with diverse mural proliferation – a hybrid lesion. Imaging Sci Dent 2011;4:29–33. Rastogi R, Jain H, Mohan C, Rastogi V, Rastogi K. Hybrid ameloblastoma – an unusual combination of desmoplastic and conventional ameloblastoma. JIMSA 2010;23.

Please cite this article in press as: Mukhopadhyay S, et al. Hybrid variant of desmoplastic ameloblastoma, a rare histomorphological entity – A case report and review of literature. J Oral Maxillofac Surg Med Pathol (2015), http://dx.doi.org/10.1016/j.ajoms.2015.05.003