[378] Determination of Oropharyngeal or Nasopharyngeal Squamous Cell Carcinoma Primary Site from Fine Needle Aspiration of Cervical Lymph Node Metastases

SR Jannapureddy, C Cohen, S Lau, JJ Beitler, MT Siddiqui. Emory University Hospital, Atlanta, GA

Background: Fine needle aspiration of head and neck tumors often involves evaluation of enlarged cervical lymph nodes. In patients with metastatic squamous cell carcinoma (SCC) in these lymph nodes, the site of origin may not be clinically evident. The distinction between oropharyngeal and nasopharyngeal primary SCC has important management consequences. A reliable method of distinction would be of clinical benefit. Previous studies have documented the utilization of human papilloma virus (HPV) detection by in-situ hybridization (ISH) and surrogate markers for HPV (p16INK4a) for oropharyngeal SCC. In the current study, we evaluate metastatic SCC for HPV type 16, 18, 31, 33, 51 (by ISH), p16 and ProExC (surrogate HPV markers), and EBER reported in nasopharyngeal SCC.
Design: Forty patients between 2004 and 2008, with adequate cell block material of cervical lymph node metastatic SCC, were identified. ISH for high risk HPV (types 16,18, 31, 33,51) and EBV (EBER), and immunohistochemistry for p16 and ProExC were performed. The site of primary SCC was obtained by medical record review.
Results: Primary site was designated in 30 cases with 23 oropharyngeal, 2 nasopharyngeal, 5 other sites (anus, cervix, lung), and 10 unknown sites. High risk nuclear HPV was detected in 9 cases (22.5 %), nuclear and cytoplasmic overexpression of p16 in 15 cases (37.5 %), ProExC in 35 cases (87.5%), and EBER in 2 cases (5%). All cases with high risk HPV ISH also showed overexpression of p16; 6 (15%) showed p16 overexpression in the absence of HPV ISH. ProExC was positive in 19 cases (47.5 %) without co-existent expression of either p16 or HPV ISH. The sensitivity for HPV infection by both surrogate markers was 100%; specificity for p16 and ProExC was 77.4% and 16.1%, respectively. Seven (30%) oropharyngeal SCC were positive for HPV ISH and negative for EBV; one nasopharyngeal SCC (50%) was EBER positive and HPV negative.
Conclusions: HPV and EBER detection can serve as indicators for oropharyngeal and nasopharyngeal primary SCC respectively, however our data show that only a subset (30%) of oropharyngeal squamous cell cancers are high risk HPV related. Additionally, despite their high sensitivity for HPV infection, surrogate markers, especially ProExC, lack specificity.
Category: Cytopathology

Monday, March 9, 2009 9:30 AM

Poster Session I Stowell-Orbison/Autopsy Award # 60, Monday Morning