Unusual osteolytic lesion of the jaw

Accepted Manuscript Title: Unusual osteolytic lesion of the jaw Author: Karine Duarte da Silva, Isadora Luana Flores, Adriana Etges, Ana Carolina Uchoa Vasconcelos, Ricardo Alves Mesquita, Ana Paula Neutzling Gomes, Sandra Beatriz Chaves Tarquinio PII: DOI: Reference:

S2212-4403(17)30985-9 http://dx.doi.org/doi: 10.1016/j.oooo.2017.06.123 OOOO 1802

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Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology

Received date: Revised date: Accepted date:

23-2-2017 24-6-2017 30-6-2017

Please cite this article as: Karine Duarte da Silva, Isadora Luana Flores, Adriana Etges, Ana Carolina Uchoa Vasconcelos, Ricardo Alves Mesquita, Ana Paula Neutzling Gomes, Sandra Beatriz Chaves Tarquinio, Unusual osteolytic lesion of the jaw, Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology (2017), http://dx.doi.org/doi: 10.1016/j.oooo.2017.06.123. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

UNUSUAL OSTEOLYTIC LESION OF THE JAW

Karine Duarte da Silva, DDS, MSc1 Isadora Luana Flores, DDS, MSc, PhD2 Adriana Etges, DDS, MSc, PhD1 Ana Carolina Uchoa Vasconcelos, DDS, MSc, PhD1 Ricardo Alves Mesquita, DDS, MSc, PhD3 Ana Paula Neutzling Gomes, DDS, MSc, PhD1 Sandra Beatriz Chaves Tarquinio, DDS, MSc, PhD1

1

Oral Diagnosis Area, Semiology and Clinics Department, Federal University of

Pelotas, UFPel, Rio Grande do Sul, Brazil 2

Oral Pathology Area, Dentistry Department, Federal University of Juiz de Fora

Campus Governador Valadares, UFJF/GV, Minas Gerais, Brazil 3

Oral Pathology Area, Oral Pathology and Surgery Department, Federal

University of Minas Gerais, UFMG, Minas Gerais, Brazil

*Corresponding Author: Sandra Beatriz Chaves Tarquinio Federal University of Pelotas, School of Dentistry Gonçalves Chaves Street, 457, ZIP Code 96015-560, Pelotas-RS, Brazil. Business fax number: +55 53 32256741 (extension 162) Home telephone: +55 53 81112894 Email adress: [email protected]

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This work was presented and awarded in the panel category of clinical cases in the XXIII Congresso Brasileiro de Estomatologia e Patologia Oral/5th World Congress of the International Academy of Oral Oncology (São Paulo, Brazil, 2015)

Conflict of Interests: None Funding: This work was supported by the MCT/CNPq/MEC/CAPES/Brazil Casadinho/Procad [grant #552662/2011-9] and by a grant to K.D.S. (scholarship) from the National Council for Scientific and Technological Development (CNPq/Brazil).

Manuscript word count (to include body text and figure legends): 2714 Number of references: 25 Number of figures: 4

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Clinical presentation An excisional biopsy specimen from a 79-year-old Caucasian man with a chief complaint of a painful swelling in the posterior left mandible was sent to the Center of Diagnosis of Oral Diseases at the Dentistry School, Federal University of Pelotas, Brazil, in 2015. The patient was fully edentulous. The color and texture of the oral mucosa were found to be normal by the surgeon. No positive lymph nodes were noted on extraoral examination. Comorbidities and evolution time of the lesion were unknown. The patient did not report a habit of smoking or daily drinking of alcoholic beverages. Radiographically, an ill-defined bilocular radiolucency was observed in the alveolar ridge, specifically in the molar region near the ramus, with an irregular osteolytic aspect (Figure 1). The clinical diagnosis established by the surgeon was ossifying fibroma (OF). Informed consent from the patient was obtained for publication of this report. Differential diagnosis For a clinical presentation of painful swelling of the posterior mandible, a number of differential diagnoses must be considered. In this case, malignant entities were more likely, owing to the clinical-radiographic aspect of the lesion, but certain benign but locally aggressive odontogenic tumors should also be considered because of certain radiographic similarities. Ameloblastoma, a tumor of epithelial origin that mainly affects the mandible, is one such benign tumor. There is no difference in prevalence between the sexes, and the mean age at diagnosis is 36 years.1,2 Radiographically, it presents as a lytic lesion with scalloped margins and resorption of the tooth roots, with the appearance of "soap bubbles" in the classic multilocular/solid type.1 This shares some

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similarity with our case. In contrast to our case, however, ameloblastoma is generally painless, and, in most cases, found radiographically, although large tumors can result in a painless swelling of the involved bone.2 Another possibility is ameloblastic fibroma (AF), which is a benign mixed tumor that occurs preferentially in the mandible, especially its posterior region, with a slight predilection for occurrence in men.3 Unlike our case, this lesion normally presents as a painless lesion and is more common in young people.3 Additionally, AF is mainly associated with an impacted tooth.4 Radiographically, it presents as an asymptomatic unilocular or multilocular radiolucency, with welldefined borders in the majority of cases, frequently with a sclerotic rim.3 This lesion usually does not lead to swelling and is often a radiographic finding; however, in some cases, it can cause bone expansion.3 This feature, along with the radiographic appearance, makes AF a possible differential diagnosis for the presented case. Odontogenic myxomas (OMs) can also have a radiographic appearance similar to the one in our case, although they are frequently painless and most commonly reported in women, especially between the second and fourth decades of life.5 OMs normally occur in the posterior mandible and they present as a locally aggressive growth with a classic honeycomb appearance on radiographic examination.5,6 Normally, the borders are well-defined.6 This type of tumor can lead to bone expansion.6 Although the location on the alveolar ridge and the presence of pain are not exclusive to OMs, it should also be considered as a differential diagnosis. Malignant odontogenic tumors such as ameloblastic fibrosarcoma (AFS), ameloblastic carcinoma (AC), odontogenic carcinosarcoma (OCS) and

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odontogenic clear cell carcinoma (OCCC) should also be listed as differential diagnosis, as they share many similarities to our case.4,7,8 AFS is a rare malignant tumor that occurs preferentially in the mandible, with no difference in incidence by sex or age.9 Radiographically, the lesion causes bone destruction and swelling with pain, similar to the present case.9 This tumor is histologically characterized by a malignant mesenchymal component with pleomorphic fibroblasts presenting hyperchromatic nuclei and atypical mitosis and an epithelial component within the normal aspect.9,10 AC is another malignant odontogenic neoplasm that exhibits aggressive behavior and shows clinically rapid growth, cortical perforation, and peripheral extension.11 ACs typically have ill-defined margins radiographically,11 similar to the radiographic findings in our case. Cytological malignant characteristics of the epithelial component of ACs can be seen in primary tumors, recurrences of an ameloblastoma, or metastatic lesions.11 The epithelial component contains many common features of malignancy, such as cellular atypia, nuclear pleomorphism, hyperchromatic nuclei, increased mitotic activity, and an increased nuclei to cytoplasm ratio.12 The spindle cell variant of AC contains a prominent population of malignant epithelial spindle cells arranged in streaming fascicles in addition to the epithelial component.10,12 Whether this lesion represents a unique entity or should be histologically grouped with other ACs is unclear.10,12 “Spindle-cell ameloblastic carcinomas” or "biphasic ameloblastic sarcomatoid carcinomas” should be distinguished from OCS.10 A jaw tumor displaying both a carcinomatous and malignant spindle cell component can be an OCS.4,10 Radiographically, this extremely rare neoplasm is quite similar to the present case, having a radiolucent aspect without defined

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borders and causing the destruction of the cortical plates.4,8,13-16 Owing to the scarcity of reported cases in the literature, the clinical significance of OCS is unclear, making it difficult to determine its prevalence with respect to age, sex, or location, although the few reported cases have shown very aggressive clinical behavior, frequent recurrence, and metastasis.4,8,13-16 Because there is so little known about OCS, it was removed from the World Health Organization classification of odontogenic neoplasms published in 20056; however, it was relisted in the current edition.17 OCCC is a rare malignant odontogenic tumor that can appear radiographically similar to the lesion in our case, as an osteolytic lesion with irregular margins.7 This lesion normally occurs in adult women, leading to a painless or painful slow-growing progressive swelling, especially in the posterior mandible. Cortical perforation and soft tissue invasion may occur, and recurrence and metastasis are common.7 Some non-odontogenic lesions, such as mucoepidermoid carcinoma, osteosarcoma, and metastatic neoplasms, also need to be listed as differential diagnosis. Mucoepidermoid carcinoma preferentially occurs in the parotid gland, but can also occur in the minor salivary glands and jaw bones. When in an intraosseous site, this lesion has female predilection, and occurs mostly in the mandible.18,19 It sometimes presents with swelling and pain.18,19 Radiographically, mucoepidermoid carcinoma usually appears as a unilocular or multilocular radiolucent lesion with sclerotic and well-defined margins.19 Normally, the cortical bone is preserved. However, cortical rupture and invasion into the surrounding soft tissue do not exclude the possibility of this diagnosis. These characteristics can also be found in other malignant tumors.6,19 For these

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reasons, central mucoepidermoid carcinoma may be considered in cases of proliferative and osteolytic lesions in the oral cavity,19 similar to the lesion presented in this report. Osteosarcoma, the most common malignant jaw bone tumor with a bone origin, arises from mesenchymal cells displaying osteoblastic differentiation and producing malignant osteoid.20 In addition, it occurs principally in the mandible, with no difference in incidence by sex or age.20,21 It clinically presents as a painless or painful swelling with ulceration and paresthesia normally associated; radiographically, bone destruction may be visible,21 similar to what we observed in this case. Different from our case, radiopaque foci can be evident with the evolution of the lesion, as well as expansion and perforation of the cortical plates.20,21 A “sunburst” radiopaque pattern is also visible in some cases.20,21 Finally, metastatic neoplasms can be another possible diagnosis for this case. Metastases from prostate, lung, thyroid, and kidney cancers may occur in the jawbones. They principally present as a rapidly progressing mass located in the mandible, accompanied by pain and paraesthesia.22 Radiographically, jawbone metastases are non-specific, but can indicate malignancy. They have a lytic radiolucent aspect with ill-defined margins and occasionally a “moth-eaten” appearance.22 Diagnosis The histopathological findings from excisional biopsy revealed a distinct biphasic neoplasm with well-demarcated islands and cords of invasive malignant epithelial cells embedded in the pleomorphic and hyperchromatic hypercellular mesenchymal cells. The epithelial neoplastic cells were polygonal or ovoid, with hyperchromatic or vesiculous nuclei, bordered by cuboidal or low

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columnar cells with inverted polarization. Some mitotic figures were also noted (Figure 2). The lesion displayed prominent immunoreactivity to p53 in both the mesenchymal and odontogenic epithelial components. Some cells of the nests and epithelial islands and some cells in the mesenchymal component were positive for Ki-67. The total proliferative index, expressed as the percentage of Ki-67-positive cells, was 10.1%. Moreover, the odontogenic epithelium was highly positive for multi-cytokeratin (AE1/AE3 antibody) and cytokeratins 14 and 19, and the mesenchymal counterpart was strongly positive for vimentin (Figure 3). The final diagnosis was OCS. Management According to the surgeon, the patient did not present with malignancy in any other sites. The tumor was stage T1N0M0. Four months after the initial curettage, a relapse of the tumor was observed. Cone beam computed tomography showed a hypodense irregular image smaller than the previous lesion (Figure 4). A marginal resection was performed, and histopathological analysis revealed the same characteristics of the initial OCS, probably denoting a tumor recurrence. The patient is currently under follow-up by the surgeon, and no evidence of recurrence or metastasis has been observed 15 months after the last surgery (Figure 4). Discussion To the best of our knowledge, the present case is the seventh case of OCS described in the English literature.4,8,13-16 OCS is an extremely rare odontogenic tumor with both epithelial and ectomesenchymal components showing cytological aspects of malignancy.8 It occurs commonly in the mandible, with no sex or age predilection, and it is normally associated with pre-

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existing lesions, such as ameloblastoma, AF, and AFS.4,8,14-16 Interestingly, OCS may arise de novo with no pre-existing disease, after several surgeries or radiation therapy.4 Considering the clinical features, an isolated painful swelling, as observed in this case, could indicate the development of a malignant tumor. Generally, malignancies in the jaws may be accompanied by a variety of clinical symptoms, the most common being pain, swelling, facial edema, bleeding, increasing tooth mobility and loosening, periodontal involvement, and trismus.6,9,11,21 OCS displays aggressive clinical behavior, with frequent recurrence and metastasis.4,15 Radiographically, OCS has a radiolucent appearance with no defined borders, as well as disruption of the cortical plates in most cases.4,8,13-16 Some cases of OCS can easily be misdiagnosed as ameloblastomas by inexperienced pathologists, owing to a failure in identifying the malignant mesenchymal component. In the recently published 4th edition of the World Health Organization’s Classification of Head and Neck Tumors, OCS was again included, after its previous exclusion. The classification of OCS as a true mixed malignant odontogenic neoplasm reveals that both the epithelial and mesenchymal components have malignant features.8,10,15,17 The epithelial component of OCS shows cords, nests, and islands of neoplastic cells presenting with enlarged and hyperchromatic nuclei. Ameloblastic architecture, with epithelial elements bordered by cuboidal or columnar cells with inverted polarization and inner stellate reticulum, can be

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observed in some areas. In addition, the tumor can show atypical mitosis and coarse chromatin.15,18 The sarcomatous component of OCS shows hypercellularity and pleomorphism, with cells displaying enlarged and hyperchromatic nuclei, and some are binucleated.15,18 Some reported cases fail to reveal the malignancy of the mesenchymal component. These characteristics are important in defining the tumor as a biphasic malignant odontogenic neoplasm. Additionally, both the epithelial and sarcomatous components grow simultaneously and at similar rates,8,10 and the lesion does not shows an epithelial-mesenchymal transition to spindle cell carcinoma.17 Immunohistochemistry is a helpful tool that can be applied in confirming a diagnosis. In an OCS case, Kim et al.4 observed positivity for cytokeratins and anti cytokeratin CAM 5.2 in the carcinomatous component, and vimentin in the sarcomatous component. Similarly, we observed positivity for cytokeratins 14 and 19, as well as multi-cytokeratin (AE1/AE3 antibody). We also observed remarkable immunoreactivity for p53 in the epithelial and mesenchymal components, and for Ki-67 in some cells from both components. The labeling of p53 in both the epithelial and mesenchymal components adds support to the diagnosis of malignancy of the two components and reinforces the diagnosis of OCS, similar to the observations of De Lair et al.8 Ki-67, an important marker of cell proliferation, is highly expressed in malignant tumors.23 However, high Ki-67 expression was not observed in the majority of cases in a retrospective analysis of malignant tumors from different origins and sites of malignancy.7,24 In our case, we found a total Ki-67 proliferative index of 10.1%.

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The low Ki-67 positivity in this case was unusual for a malignant tumor; however, Ki-67 is a sensitive cell cycle-associated nuclear protein that has variable expression during the active phases of the cell cycle, and is not expressed in G0.23 Additionally, of the six OCS case reports in the literature, only two presented immunohistochemical analyses for Ki-67.8,15 These authors found a high proportion of proliferating cells in both components of OCS. As there are so few OCS cases reported in the literature, it is difficult to determine whether the pattern of Ki-67 labeling in this specific neoplasm is consistent. Owing to its clinical aggressiveness and high association with metastasis and recurrence, OCS requires strict follow-up.4,15 Because OCS is quite a rare condition, and not all of the reported cases have included long-term follow-up, it is difficult to determine the prognosis of OCS patients. However, death is a common event, especially in cases with metastasis.4 The second presentation of the reported case represented a recurrence, which may have been caused by neoplastic cells that remained in the site after the first intervention, despite excision by curettage having been performed in an attempt to remove the entire tumor. The treatment of choice for OCS is surgery.4,8,13-16 It is common for the patient to undergo several surgeries, owing to frequent recurrence.4,13 The use of adjuvant radiotherapy in such cases is still under debate, partially owing to the possibility that the tumor might not respond to the radiotherapy. 4 Therefore, if the tumor is detected early, surgical treatment alone will most likely lead to a better prognosis.4,8,14 Additionally, the clinical diagnosis of OF presented by the surgeon was completed discarded. Although OF can begin as a radiolucent unilocular lesion

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usually occurring in the premolar and molar regions of the mandible, it is generally a painless, mixed, radiolucent, and radiopaque lesion.25 It is possible that the surgeon established the clinical diagnosis of OF by interpreting the radiographic aspect as an initial fibro-osseous condition. However, the radiographic aspect of the present case reflects the process of irregular bone resorption caused by the pathologic condition, giving the appearance of radiolucency with ill-defined limits. In conclusion, we report the seventh case of OCS, a rare malignancy with aggressive behavior. This condition may clinically mimic other pathological entities. Therefore, it is important to obtain a proper anamnesis, as well as to establish the differential diagnosis and proceed to investigate for suspected metastases. The histopathological diagnosis of this disorder is not difficult, but should be rigorously conducted, as an OCS diagnosis suggests high rates of recurrence and metastasis and requires thorough and periodic follow-up.

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Figure 1. Panoramic radiograph: Initial aspect showing an osteolytic lesion in the left posterior alveolar ridge. Figure 2. Photomicrographs of OCS (Hematoxylin and eosin, A-F). AOdontogenic epithelial nests and islands in a hypercellular mesenchymal tissue. Clear cells and some typical ameloblastic architecture can be seen with peripheral cuboidal and low columnar epithelial cells showing inverted polarization (200x). B- Odontogenic epithelial island showing pleomorfism and mesenchymal tissue presenting mitotic figures pointed by red arrows (200x). CMesenchymal component displaying nuclear anaplasia (200x). D- Odontogenic epithelial nests embedded in a malignant mesenchymal tissue (400x). E and FMesenchymal tissue displaying many fibroblasts with enlarged and hypercromatic nuclei and some mitotic figures pointed by red arrows (400x). A high-resolution version of the image is available as eSlide: VM04091. Figure 3. Photomicrographs of OCS (Immunohistochemistry, 200x, A-F). AOdontogenic epithelium highly positive to AE1/AE3, B- cytokeratin 14 and Ccytokeratin 19. D- Mesenchymal counterpart strongly positive to Vimentin. EProminent immunorreactivity to p53 in both mesenchymal and odontogenic epithelial components. F- Immunoreactivity to Ki-67 in scarce epithelial and mesenchymal cells. High-resolution versions of the slides for use with the Virtual Microscope are available as eSlides: VM04092, VM04093, VM04100, VM04101, VM04102, VM04103. Figure 4. Cone beam tomography (A-E). A, B and C- 4 months after the first surgery. A- Panoramic view reflecting an incomplete excision of OCS. B and CParasagittal consecutive views displaying hypodense area with irregular borders in left alveolar ridge. D and E- 15 months after the last surgery. D-

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Panoramic view revealing no evidence of recurrence. E- Parasagittal view showing only a bone depression with well-defined margins.

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