Chondroblastic osteosarcoma mimicking periapical abscess

Abstract Lesions of non-endodontic origin may mimic periapical abscess. Osteosarcoma is a rare malignant lesion. Case report The present report describes a case of chondroblastic osteosarcoma in the periapical region of teeth #29, #30, and #31 of an 18-year-old male. Clinical history showed self-reported discomfort in the right posterior gingiva for over a month. Physical examination showed a small expansion and redness of the right mandibular buccal and lingual cortical plates, but no signs of pain or inflammation were observed. All the teeth responded positively to pulp sensibility. Periapical and panoramic radiographs showed slight periapical radiolucency in the roots of teeth #29 and #30, clear periodontal ligament space widening, and evident loss of lamina dura. Incisional biopsy was performed, and based on microscopic findings the diagnosis of chondroblastic osteosarcoma was confirmed. Conclusions Non-endodontic diseases associated with tooth root apex, such as chondroblastic osteosarcoma, should be included in differential diagnosis of jaw lesions that resemble periapical abscess.


Introduction
A periapical radiolucency associated with a vital tooth constitutes a diagnostic challenge 2 . Periapical lesions can be of endodontic or non-endodontic origin.
Therefore, periapical radiolucency associated with root apices showed by radiographic examinations may be or not a consequence of infection of the root canal system 4,12,13 , which may involve progressive changes in periapical structures with subsequent bone resorption 12 . Conventional radiographic images are frequently used to detect apical periodontitis.
The diagnosis of a periapical radiolucency requires careful and correct management of information obtained from patient history, clinical examination, pulp vitality testing, and radiography analysis 2,4,13 .
The establishment of diagnostic procedures, such as examination of signs and symptoms, as well as complementary examinations, is indispensable to obtain differential diagnosis. Lesions of non-endodontic origin may be associated with the periapical area of the tooth 3,5,8,16,18 .
In the present report we describe a case of chondroblastic osteosarcoma resembling a periapical abscess in an 18-year-old male.

Case report
An 18-year-old male patient was referred to the dental clinic of the Federal University of Goiás (Goiânia, GO, Brazil) with a chief complaint of a "discomfort on the right posterior gingiva" for over a month. At physical examination, a small expansion and redness were found in the buccal and lingual cortical plates of the right mandible in the region of teeth #29, #30, and #31, but no signs of pain or inflammation were observed ( Figure 1A). The overlying mucosa appeared intact.
Periapical and panoramic radiographs showed periapical radiolucency ranging from 4 to 5 mm in the mesial and distal roots of teeth #29 and #30, a slight rarefaction of the inter-dental alveolar bone, a clear periodontal ligament space widening, and an evident loss of lamina dura (Figure 1 B-C).
The patient reported no history of dental trauma.
Neither cracks on the crowns of teeth #29 and #30, particularly on the mesial and distal marginal ridges, nor previous restorative treatments, were found. Pulp vitality testing using tetrafluoroethane spray (Endo-Ice; Hygenic Corp, Akron, OH) confirmed positive response in all teeth associated with radiolucent lesions, and therefore root canals were not treated.    In the case reported here, clinical findings were in accordance with previous descriptions of osteosarcoma 6,9,  In summary, osteosarcomas could present similar features of some inflammatory periapical lesions, such as periapical abscess, since it also present pain, swelling and variable radiographic changes 3 .
Exceptional care should be paid to endodontic diagnoses based on clinical and radiographic findings.
Since periapical lesions of non-endodontic origin may mimic periapical abscess and apical periodontitis, they Chondroblastic osteosarcoma mimicking periapical abscess should be considered before root canal treatment.

Conclusions
Non-endodontic diseases associated with tooth root apex, such as chondroblastic osteosarcoma, should be included in the differential diagnosis of jaw lesions that resemble periapical abscess. Periapical lesions may be misdiagnosed at their early stages if malignant tumors are not suspected.