Journal of Cancer Research and Therapeutics

CORRESPONDENCE
Year
: 2018  |  Volume : 14  |  Issue : 2  |  Page : 471--474

Parosteal osteosarcoma of mandible: A rare case report


Swati Gupta1, Shilpa Parikh2, Sumit Goel1,  
1 Department of Oral Medicine and Radiology, Subharti Dental College, Swami Vivekanand Subharti University, Meerut, Uttar Pradesh, India
2 Department of Oral Medicine and Radiology, Government Dental College and Hospital, Ahmedabad, Gujarat, India

Correspondence Address:
Dr. Swati Gupta
Department of Oral Medicine and Radiology, Subharti Dental College, Swami Vivekanand Subharti University, Subhartipuram, NH-58, Delhi Haridwar Bypass Road, Meerut - 250 005, Uttar Pradesh
India

Abstract

With the exception of multiple myelomas, osteosarcoma is the most frequently occurring primary malignant bone tumor with an overall incidence of 1:100,000/year. It has greatest predilection for the metaphyses, most frequently femur and tibia. However, osteosarcomas affecting the craniofacial bones are infrequent. Two main types: intramedullary and juxtacortical varieties are seen. Juxtacortical variety is further subdivided into periosteal and parosteal variants. Due to its rarity, only 13 cases of parosteal osteosarcoma have been reported till date. A 35-year-old male patient with affected postirradiated mandible is being reported as the 14th case of this kind with its unique benign presentation and less aggressive nature.



How to cite this article:
Gupta S, Parikh S, Goel S. Parosteal osteosarcoma of mandible: A rare case report.J Can Res Ther 2018;14:471-474


How to cite this URL:
Gupta S, Parikh S, Goel S. Parosteal osteosarcoma of mandible: A rare case report. J Can Res Ther [serial online] 2018 [cited 2020 Jul 8 ];14:471-474
Available from: http://www.cancerjournal.net/text.asp?2018/14/2/471/176420


Full Text



 Introduction



The term first used by Alexis Boyer in 1805, “osteosarcoma” represents the most common nonhematopoietic primary malignant bone tumor. In the head and neck region, they account for only 6–10% of all osteosarcomas.[1] Osteosarcomas of the jaw bones are very rare, with an incidence of 0.7/million, and are more frequent in the mandible than in the maxilla. They usually present in the third and fourth decades of life, almost a decade after their presentation in long bones.[2] Its induction is promoted by Rb and p53 inactivation localized to 17p13 and 13q14, respectively. Cytogenetic abnormalities should also be checked in chromosomes 1, 6, 9, 10, 11, 12, 14, and 15.[3]

Zarbo and Carlson have classified osteosarcomas by their site of origin into – conventional/intramedullary, juxtacortical (arising from periosteal surface), and extraskeletal osteosarcomas.[4] Juxtacortical osteosarcoma (incidence of 0.07/100,000 population) has two clinicopathologic variants: parosteal (low-grade) and periosteal (high-grade).[5]

To date, only 28 cases of juxtacortical osteosarcomas have been reported of which 13 were parosteal type, nine were periosteal, and six were of periosteal/parosteal type.[6] The present case brings the total number of parosteal osteosarcomas of jaws to 14, a rarity in itself in the literature.

 Case Report



A 35-year-old male patient reported with a complaint of pus discharge from the left side of the face for 9 months. Three months back, his left lower second premolar and molars exfoliated. He gave a history of surgery followed by radiotherapy for nasopharyngeal angiofibroma 18 years back and history of tuberculosis and extraction of upper left posterior teeth 4 years back.

On examination, there was a single diffuse, slightly tender, and firm swelling anteriorly, discolored skin and extraoral sinus opening posteriorly [Figure 1]. No lymphadenopathy was present. Intraorally, a single 6 cm × 4 cm × 3 cm sized bluish red pedunculated, slightly tender, lobulated, and firm irregular growth was present on the lower left alveolar ridge with superficial ulceration and indentations of lower teeth [Figure 2]. It was protruding out from left corner of the mouth and pushing tongue to the opposite side. Both upper and lower teeth in vicinity of the growth were grade III mobile. Clinical differential diagnosis of osteoradionecrosis in association with metastatic tumor and osteosarcoma were made.{Figure 1}{Figure 2}

Panoramic radiograph [Figure 3] showed mixed radiolucent radiopaque pattern in the lower left quadrant with pathologic fracture. Hanging drop appearance of the upper left canine was seen. The findings of computed tomography were suggestive of malignant mass (irregular heterogeneously enhancing mass) of 46 mm × 76 mm in the left buccal mucosa, involving upper and lower gingivobuccal sulcus with significant soft tissue component abutting oral tongue and extending into buccinator space, root of zygomatic arch, pterygopalatine fossa, and infratemporal fossa [Figure 4]. There was erosion of the upper and lower alveolus, posterior wall of right maxillary sinus. Enlarged lymph nodes measured 17 mm × 16 mm in the left level IB. Incisional biopsy from the growth was in favor of pyogenic granuloma; however, based on clinical and radiographic findings, left hemimandibulectomy was planned and surgical specimen was then sent for histopathological examination [Figure 5].{Figure 3}{Figure 4}{Figure 5}

On histopathological examination, gross tumor mass of size 6 cm × 6 cm × 4.5 cm arising from the surface of the mandible showed proliferation of well-differentiated fibroblastic cells with osteoid. Pleomorphism was not present. Mitosis present was 4–6/10 hpf at active area. Atypical mitosis was absent [Figure 6]. All surgical margins were free of tumor.{Figure 6}

On the basis of clinical, radiological, histopathological features, a diagnosis of parosteal osteosarcoma of the mandible was made.

 Discussion



In 1949, Geschickter and Copeland were the first to describe parosteal osteosarcomas. These are rare, low-grade juxtacortical variant of osteosarcoma, especially in the jaws, representing 1.6% of all bony malignant tumors and up to 5% of all osteosarcomas. Only 13 cases of intraoral parosteal osteosarcoma have been reported in the English literature. The presenting patients varied from 13 to 68 years with the average age being 38 years with equal sex predilection. The maxilla was more commonly affected with eight cases, whereas the mandible was affected in five cases.[6],[7] In the present case, mandibular involvement was seen in a 35-year-old male patient.

Well-recognized risk factors include preexisting bone abnormalities, hereditary retinoblastoma, Li–Fraumeni syndrome, Rothmund–Thomson syndrome, and history of radiation exposure,[8] which was seen 18 years back in the present case. Osteosarcoma results from the administered radiation being unable to destroy all viable cells, but is able to induce malignant transformation.[9]

The clinical presentation of the parosteal variant of osteosarcomas is as an expansile lesion on the involved bone, with a nonlobular outer surface, and a potential for overlying mucosal ulceration as was seen in our case.[1]

Radiographically, it is characteristically radiodense and homogeneous, more at the base than at the periphery unlike periosteal variety, which is not as radiodense and has a poorly defined periphery. Parosteal osteosarcomas appear as a lobulated nodule attached to cortical bone by means of a short pedicle and usually overgrow its base of origin whereas periosteal osteosarcoma tends to remain within the confines of its base. There is no radiographic continuity with the underlying marrow cavity in both varieties. The thin periosteal radiolucency, about 1–3 mm in width (“string sign”) which separates the tumor from the subadjacent cortex, is quite characteristic of parosteal osteosarcoma, but is present only in about 30% of the cases. New periosteal bone formation is absent. Since treatment and prognosis varies with both the variants of surface osteosarcomas, radiologic differentiation is important.[3],[5]

Due to the nonaggressive and noninvasive nature of parosteal osteosarcoma, it must be distinguished from other benign lesions such as osteoma or torus, osteoblastoma, and osteochondroma; and several other differential diagnoses can be considered as metastatic carcinoma, intramedullary osteosarcoma, chondrosarcoma, and subpontic hyperostosis.[7],[9]

Histologically, parosteal osteosarcoma is well-differentiated, characterized by spindle cell stroma with minimal atypia and rare mitotic figures separating irregular trabeculae of woven bone. It often presents with indolent behavior and a bland-looking microscopic appearance in the early stages of the disease, and the final diagnosis is often only reached after repeated biopsies or treatment as was seen in our case and that reported by Ong et al.[10] These generally have a favorable prognosis, better in mandible than maxilla when compared to conventional and periosteal osteosarcomas. Treatment of choice is wider resection with negative surgical margin.[1],[5]

 Conclusion



This case contributes to the literature of the rare variant of osteosarcoma - the parosteal osteosarcoma and must be differentiated from other benign osseous lesions due to its less aggressive biological behavior. The presence of soft tissue mass arising from gingivobuccal sulcus in postradiation cases must be viewed with a suspicion of juxtacortical osteosarcomas.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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