Indian Journal of Dental Research

: 2013  |  Volume : 24  |  Issue : 5  |  Page : 631--634

A guise of osteosarcoma: Chondroblastoma-like

Aditi Amit Byatnal1, Anuradha CK Rao2, Monica C Solomon1, Raghu A Radhakrishnan1,  
1 Department of Oral and Maxillofacial Pathology, Manipal College of Dental Sciences, Manipal University, Karnataka, India
2 Department of Surgical Pathology, Kasturba Medical College, Manipal, Karnataka, India

Correspondence Address:
Raghu A Radhakrishnan
Department of Oral and Maxillofacial Pathology, Manipal College of Dental Sciences, Manipal University, Karnataka


Osteosarcoma (OS) is a rare tumor arising from immature bone forming cells or through neoplastic differentiation of other immature mesenchymal cells into osteoblasts. Chondroblastoma-like OS is one of the rare forms of OS to be seen in jaw bones. Aggressive clinical behavior, osteolytic areas in the radiograph and histological presentation of chondroblastoma such as cells with grooved nuclei, typical chicken-wire calcification along with areas of tumor osteoid, implied the diagnosis as chondroblastoma-like OS. Use of reticulin stain further confirmed the diagnosis. A case of chondroblastoma-like OS is reported, emphasizing the importance of early diagnosis of aggressive jaw lesions with the help of routine radiography, histopathology, and special stains.

How to cite this article:
Byatnal AA, Rao AC, Solomon MC, Radhakrishnan RA. A guise of osteosarcoma: Chondroblastoma-like.Indian J Dent Res 2013;24:631-634

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Byatnal AA, Rao AC, Solomon MC, Radhakrishnan RA. A guise of osteosarcoma: Chondroblastoma-like. Indian J Dent Res [serial online] 2013 [cited 2020 Aug 10 ];24:631-634
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Full Text

Osteosarcoma (OS) is a malignant tumor characterized by direct formation of bone or osteoid by tumor cells. It is the most common primary malignant bone tumor occurring in the long bones. [1] It is characterized by frankly to subtly anaplastic stromal cells with evidence of direct formation of osteoid and/or primitive bone by these cells. OS constitutes 20% of all the bone tumors [1] and 0.2% of all the sarcomas. Jaw osteosarcoma (JOS) constitutes about 6-7% of OSs, [2],[3] and is a relevant entity by virtue of the increase in the mean age of occurrence, aggressive behavior, late, and less rate of metastasis and better prognosis. Chondroblastoma-like OS, a rare variant of OS of jaw, which exhibits features of chondroblastoma is disparate entity that needs to be delineated from chondroblastic OS, [4] and chondroblastoma, [5] the two closely related yet distinct entities, which occur infrequently in the jaw bones The importance of clinical examination, relevant diagnostic imaging, and pertinent histological connotation in establishing the diagnosis of chondroblastoma-like OS is highlighted.

 Case Report

A 17-year-old male patient reported with a complaint of swelling in the floor of the mouth of 2 months duration. History revealed that the patient had consulted a local dental surgeon 1 month prior to visiting us where surgical excision of the lesion was attempted. The diagnosis from the earlier report pointed to a benign fibro-osseous lesion. Further inquiry revealed that the swelling recurred and increased in size following surgery along with extrusion and loosening of lower anterior teeth.

Lesional examination revealed a 3 cm × 3 cm reddened swelling in the floor of the mouth extending from 33 up to 45. The swelling was well-defined, firm, and tender with a mucosal wound on the superior aspect that was covered with slough, and surrounded by an erythematous margin. The swelling extended antero-superiorly up to the lingual gingiva spanning from 32 to 44. Grade III loosening of teeth and tenderness was noted with respect to 41, 42, and 43. Although the lingual aspect of the lower jaw seemed elevated, there was no evident expansion of the bony plates [Figure 1]. Submental and bilateral submandibular lymph nodes were about 1 cm × 1 cm in size, firm, mobile, and non-tender on palpation.{Figure 1}

Radiograph revealed an osteolytic area with a poorly defined border in relation to 42 and 43 along with asymmetric widening of the periodontal ligament space noted with respect to 41, 42, 43, and 44 [Figure 2]. Routine hematological investigation yielded values, which were within the normal limits and serum alkaline phosphatase level was about 111 IU/L. Based on the clinical evidence of rapidly evolving swelling and widening of periodontal ligament space by radiographic examination, malignancy of bone could not be ruled out as both OS and chondrosarcoma were considered in the differential diagnoses.

Histological examination of the surgically excised specimen revealed islands of polygonal plasmacytoid osteoblasts with anisonucleosis, prominent nucleoli and moderate to abundant amphophilic cytoplasm were seen [Figure 3]. Some of the cells with grooved nuclei resembled chondroblasts [Figure 4]. Chondroblastoma-like areas with punctuate, spotty, and chicken-wire calcifications forming a filigree pattern were also present [Figure 5], accompanied by focal woven bone formation. Numerous vascular channels were interspersed throughout and infiltration of the tumor into soft-tissue and skeletal muscle was observed. Special stain for reticulin fibers showed a honeycomb pattern around individual cells [Figure 6]. Based on the classical histological presentation aided with clinical and radiographic findings a diagnosis of well-differentiated chondroblastoma-like OS was given.{Figure 2}{Figure 3}{Figure 4}{Figure 5}{Figure 6}

Further investigation with bone scan scintigraphy showed an increased uptake of radioisotope in the mandible [Figure 7], suggestive of either local infiltration or reactive changes with no evidence of bone metastasis while computer tomography of thorax demonstrated three focal radiopacities in the left lung [Figure 8] suggestive of lung metastasis. Patient was advised chemotherapy with doxorubicin 45 mg/m 2 IV + cisplatin 50 mg/m 2 IV and the cycle was repeated every 3 weeks with a maximum of 6 cycles. Patient is at present apparently disease free and on regular follow-up.{Figure 7}{Figure 8}


JOS is a rare tumor of the jaw bone, which arise from immature bone forming cells or through neoplastic differentiation of other immature mesenchymal cells into osteoblasts. In the mandible, JOS is particularly confined to the angle and ramus area. [6],[7] However, cases of JOS occurring in mandibular symphysis area [8] have been reported as was noted in our case. In rare instances, JOS in the maxilla involving maxillary antrum have also been reported. [9] The common presenting features in JOS include swelling, pain or tenderness, paresthesia and mobility or loosening of associated teeth. In our case, the patient's primary concern was a mass in the lower anterior region resulting in the loosening of teeth on the affected side.

JOS usually produces a poorly defined, irregularly destructive bone lesion interspersed with areas of radiopacity. However, in some instances, it may be completely radiolucent as was noted in our case. JOS involving the alveolar process may produce widening of PDL space as the neoplasm extends into the ligament. Some investigators emphasize this to be an important hallmark of early JOS. [10],[11] This finding along with clinical presentation and histological presentation of islands of polygonal plasmacytoid osteoblasts with anisonucleosis and chondroblastoma such as areas with punctuate, spotty, and chicken-wire calcifications forming a filigree pattern aided in arriving at a definitive diagnosis.

We distinguish our case from two other closely related yet dissimilar entities namely the chondroblastic variant of OS [4] and chondroblastoma. [5] The chondroblastic variant of OS characteristically depicts hypercellular osteoid with numerous hyperchromatic spindle cells, prominent masses of chondroid interspersed with bizarre, pleomorphic cells, and lobular areas of malignant cartilage cells with few areas of tumor osteoid. [6] On the other hand, chondroblastoma presents as round, plump chondroblasts having a bean shaped nuclei with grooves enmeshed in chondroid matrix, showing varying amounts of chicken-wire calcification. [5] Our case displayed the features of chondroblastoma interspersed with islands of polygonal, plasmacytoid osteoblasts, and areas of tumor osteoid.

Distinguishing these two entities is of paramount importance as chondroblastoma being a benign tumor has to be treated by conservative surgical excision. [5] Chondroblastoma-like OS, on the other hand has to be treated surgically with chemotherapy since OS is considered to be radioresistant. Surgical excision with prophylactic chemotherapy increases the survival rate and decreases the frequency of recurrence and metastasis. [1] It must also be emphasized that early diagnosis of JOS has better prognosis with overall 5 year survival rate of 63%. [7]

The chondroblastoma-like OS described here is one of the rare histological subtypes of OS, which mimics chondroblastoma. To the best of our knowledge, this is the first case of its kind to be reported in the jaw bone. This case highlights the importance of early diagnosis of JOS and appropriate treatment planning thereby improving patient prognosis.


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