Eccentric, mature osseous cap: A distinct imaging feature of sinonasal osteoblastoma.

BACKGROUND: With the exception of osteomas, bone neoplasms that originate in the sinonasal cavity are seldom diagnosed on preoperative imaging due to a lack of characteristic radiographic features. Here we described the unusual occurrence of an osteoblastoma in the paranasal sinuses, and we drew focus to its salient imaging features. A highly unique imaging sign was indicated, and its pathologic basis was explained, with concurrent review of the literature. METHODS: Case series and review of the literature. RESULTS: Two cases of sinonasal osteoblastoma were managed by definitive surgical resection. Both tumors on preoperative computed tomography demonstrated an expansile, heterogeneous fibro-osseous lesion with an eccentric, mature osseous cap. The dense osseous cap seen on imaging corresponded to a rim of mature bone on histopathology. A review of existing literature revealed the presence of this imaging sign in all reported cases. CONCLUSION: Sinonasal osteoblastoma is an extremely rare entity with undefined imaging characteristics to guide preoperative decision-making. Here we reported, to our knowledge, the first description of a characteristic imaging sign of an eccentric, mature osseous cap, which corresponded histologically to a single peripheral layer rim of osteoblasts, a unique trait of osteoblastoma.

Utility of intraoperative frozen sections in surgical decision making for acute invasive fungal rhinosinusitis.

BACKGROUND: Acute invasive fungal rhinosinusitis (AIFRS) represents a fulminant, potentially fatal, disease process in immunocompromised patients. The diagnosis often rests on high index of clinical suspicion, with relative paucity of data on the diagnostic and therapeutic implications of intraoperative frozen sections. METHODS: Retrospective review was performed for 18 cases undergoing endoscopic sinus surgery for AIFRS. Reliability of intraoperative frozen section diagnosis was evaluated for all patients using final pathology as the gold standard. RESULTS: A total of 66 frozen sections were performed. Diagnostic accuracy of frozen sections illustrated sensitivity of 72.7% (95% confidence interval [CI], 0.57 to 0.85), specificity of 100% (95% CI, 0.85 to 1.00), positive predictive value (PPV) of 100% (95% CI, 0.89 to 1.00), and negative predictive value (NPV) of 64.7% (95% CI, 0.46 to 0.80). There was no statistically significant difference in sensitivity of frozen sections in cases of Mucor and Aspergillus at 68.8%% and 76.2%, respectively (p = 0.61). CONCLUSION: This study represents the largest series assessing the diagnostic accuracy of frozen section analysis in AIFRS. Frozen section analysis is an effective tool for guiding intraoperative decision making in patients with AIFRS with a high PPV. A Low NPV underscores the importance of clinical suspicion and intraoperative decision making based on endoscopic findings when negative frozen section results are encountered. Further, frozen section analysis appears to be equally effective in detecting either Mucor or Aspergillus.