Update on sinonasal malignancies

Introduction to Sinonasal Tract Malignancies

  • Sinonasal tract malignancies are rare, making up about 1% of all human cancers and less than 5% of head and neck cancers.

  • They primarily occur in the maxillary sinus, nasal cavity, and ethmoid sinus.

  • These cancers pose diagnostic challenges due to overlapping histological features among different tumor types.

Diagnostic Challenges

  • Pathologists face difficulties in differentiating between various sinonasal cancers due to similarities in histology.

  • Accurate diagnosis is crucial because these tumors can invade adjacent structures leading to serious complications.

  • The adoption of functional endoscopic sinonasal surgery has improved specimen sampling and resection capabilities, aiding diagnosis.

Objective and Approach

  • The review aims to create a streamlined algorithm to facilitate diagnosis using histological clues, immunohistochemical profiles, and molecular assays.

  • Distinct immunohistochemical and molecular markers can assist in differentiating cancer types despite their similar histology.

Emerging Sinonasal Tumors

HPV-Related Multiphenotypic Sinonasal Carcinoma

  • Previously referred to as HPV-related carcinoma with adenoid cystic features, now recognized for varied histology.

  • Predominantly affects females with typical symptoms of epistaxis or nasal obstruction.

  • High recurrence rate (35%) but no cancer-related mortality reported.

  • Histological features include solid sheets and cribriform nests with basaloid appearance; strong expression of p16 and positive for high-risk HPV.

NUT Carcinoma

  • A more aggressive tumor predominantly seen in young adults, often found in the sinonasal tract.

  • Symptoms include nasal obstruction, pain, and headaches; patients frequently present with metastatic disease.

  • Poor prognosis with a 30% survival rate; distinct histological appearance shows nests of small round blue cells and squamous differentiation features.

Lymphoepithelial Carcinoma

  • Associated with Epstein-Barr virus, predominantly occurs in males, especially in Southeast Asia.

  • Features an undifferentiated appearance with lymphoplasmacytic infiltrate.

  • Generally has favorable prognosis despite nodal involvement; commonly expresses p63, p40, and shows patchy p16 expression.

SWI/SNF-Deficient Carcinomas

  • Characterized by mutations in SWI/SNF complex, often presenting with variable histologies.

  • SMARCB1-deficient tumors exhibit uniquely basaloid or rhabdoid features.

  • Prognosis tends to be poor, with many patients dying within two years of diagnosis.

Biphenotypic Sinonasal Sarcoma

  • Typically found in the nasal cavity, characterized by infiltrative spindle cells.

  • Molecular profile shows PAX3 fusion, among others, with a relatively good prognosis over time.

Adenocarcinomas of Sinonasal Tract

Sinonasal Adenocarcinoma

  • Divided into intestinal and nonintestinal types, with various unique entities under nonintestinal adenocarcinomas.

  • Most cases show seromucinous differentiation; specific mutations and fusions have been associated with certain tumor types.

  • Recent emerging entities include sinonasal adenocarcinoma with ETV6::NTRK3 fusions.

Tumors of Neuroectodermal Origin

Olfactory Neuroblastoma and Carcinoma

  • Olfactory neuroblastoma originates from the olfactory epithelium and exhibits a round blue cell morphology with neuroendocrine differentiation.

  • Olfactory carcinoma shares similarities but shows varying keratin markers and distinct clinical behavior.

  • Treatment approaches include somatostatin receptor targeting, which has shown promise in clinical trials.

Progress in Molecular Diagnostics

  • Advances have led to improved classification of sinonasal tumors based on genetic alterations and methylation profiling.

  • IDH mutations indicate a specific tumor category with better prognostic outcomes, as opposed to IDH-wild-type tumors.

  • Comprehensive genetic profiling can clarify the differentiation between similar malignancies and direct targeted therapies.

Conclusion

  • Sinonasal malignancies exhibit a diverse array of histological features and molecular characteristics.

  • A systematic diagnostic approach leveraging clinical data, immunohistochemistry, and molecular assays is advised for accurate tumor classification.

  • Continuous research is essential for further understanding of these tumors and enhancing patient prognosis.