Primary Intraosseous Squamous Cell Carcinoma of the Jaws

Primary intraosseous squamous cell carcinoma is a rare form of squamous cell carcinoma, arising within the jaws.To clarify the clinicopathologic and behavioral spectrum of primary intraosseous squamous cell carcinoma.The clinical and pathologic findings, treatment, and follow-up data of 39 cases of primary intraosseous squamous cell carcinoma were collected and analyzed.Of the 39 patients, 26 (67%) were men and 13 (33%) were women. The age at diagnosis ranged from 24 to 82 years (mean, 54 years). The tumors occurred predominantly (84.6%) in the posterior mandible. Microscopically, all tumors demonstrated general features of a squamous cell carcinoma; 19 of which (49%) also showed features suggestive of an odontogenic origin. The overall survival rates were 69.8% at 2 years and 36.3% at 5 years. Univariate analysis showed that tumors with or without odontogenic features, tumor grading, lymph node metastasis, and treatment modalities were significant prognostic factors for survival, but multivariate analysis showed that only histologic grading (relative risk, 4.43; P = .03) remained a significant prognostic factor. The cumulative probabilities of recurrence were 55.7% at 2 years and 75.9% at 5 years. Univariate analysis showed that lymph node metastasis and treatment modalities were significant prognostic factors for recurrence. On multivariate analysis, however, only lymph node metastasis remained a significant prognostic factor (relative risk, 2.54; P = .05).Primary intraosseous squamous cell carcinoma is a high-grade malignancy with frequent, regional lymph node metastasis and high rates of recurrence and mortality. The tumor grading and regional lymph node metastasis may serve as useful indicators for prognosis.