Primary intraosseous squamous cell carcinoma: a clinical, radiographic and histopathological challenge

Abstract

Background

This case illustrates the clinical challenges associated with primary intraosseous squamous cell carcinoma (PIOSCC). This rare entity can arise from otherwise-benign odontogenic cysts, leading to delays in diagnosis and management. The clinical, radiographic, and histologic features of PIOSCC can be heterogeneous, thus creating a diagnostic challenge for clinicians.

Case Summary

This otherwise-healthy 45-year-old man with a history of a childhood accident leading to anterior tooth loss and subsequent bridge placement in 2017, presented at the dentist in 2021 with a 1-year history of swelling and pain in the left maxillary alveolus. On examination, the radiographs showed a well-defined, corticated, homogenously radiolucent entity centered at the apices of 8, 10, 11, and edentulous 9 area, in which it was interpreted as a radicular cyst. He was subsequently referred to the endodontist but declined treatment because of cost. In October 2022, he presented again with a swollen and irregular appearance of the anterior maxilla and adjacent white mucosal patch measuring 1 × 1 cm. An immediate referral was made to an oral surgeon at the local hospital, and an intraosseous biopsy was performed showing a cystic lesion with well-differentiated squamous cell carcinoma. The patient was referred to the Odette Cancer Centre at Sunnybrook Health Sciences Centre and underwent a surgical resection and a bilateral neck dissection with the ENT team in May 2023. The pathologic examination confirmed a well-differentiated squamous cell carcinoma, staged as pT1N0M0. The patient is currently 6 months postrecovery and is doing well.

Conclusion

PIOSCC manifests as a jaw carcinoma originating from odontogenic cysts or remnants of odontogenic epithelium surrounding teeth, as defined by the World Health Organization (5th edition). This case presents as a diagnostic dilemma given the presence of the superficial mucosa changes and the underlying benign appearing cystic entity. Careful analysis of the specimen by an experienced pathologist is critical in these cases to identify the true origin of this tumor. Careful correlation of the clinical and radiographic findings, along with a timely biopsy, is also imperative for the precise diagnosis and effective management of PIOSCC.