Nasopharyngeal Carcinoma vs Sinonasal Carcinoma

Typically a case is likely to present with an FNA or biopsy from a suspicious lymph node and on imaging shows a tumour eroding in the nasal region. The differential diagnosis is likely to include the following:

Nasopharyngeal Carcinoma

  • Distinct epidemiology – seen particularly in China (Hong Kong) and Africa
  • Keratinising SCC, Non-keratinising SCC and Undifferentiated pattern.  Undifferentiated nasopharyngeal carcinoma is associated with abundant lymphocytes and is sensitive to radiotherapy.
  • The undifferentiated form typically shows large epithelial cells with oval and round vesicular nuclei with indistinct cell borders in a syncytial pattern and with abundant normal appearing T-lymphocytes.
  • Small primary + cervial lymph nodes, little destruction or spread beyond site of origin. Mitoses, necrosis & vascular invasion not a prominent feature.
  • Associated with EBV therefore shows EBER +ve. Also shows high molecular weight cytokeratin positivity (CK5/6). CK7 neg.
  • Typically presents with nodal metastasis

Sinonasal Carcinoma

  • Rare pleomorphic carcinoma and is usually EBV negative, non keratinising and shows no significant lymphocytic infiltrate.
  • Large primary +/- cervical lymph nodes, with marked destruction & spread beyond site of origin. Trabeculae, nests, sheets. Very prominent mitoses, necrosis, vascular invasion.
  • Typically presents with nodal metastasis.
  • IHC – EBV, CK5/6 & 13 neg. CK7 sometimes positive.

Squamous Cell Carcinoma

Adenocarcinoma

Non Hodgkin’s (large cell) lymphoma

Reference:

Robbins and Cotran. Pathologic Basis of Disease. 8th Ed. 751pg

Gattuso et al. Differential Diagnosis in Surgical Pathology. 2nd Ed.

Dabbs. Diagnostic Immunohistochemistry. 2nd Ed.

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