[1338] Spindle Cell Carcinomas of the Head and Neck Are Rarely Associated with Human Papillomavirus

Rao F Watson, Rebecca D Chernock, Hongwei Wang, Xiao-Jun Ma, Yuling Luo, Samir K El-Mofty, James S Lewis. Washington University School of Medicine, Saint Louis, MO; Advanced Cell Diagnostics, Inc., Hayward, CA

Background: Spindle cell carcinoma (SpCC) is a rare variant of squamous cell carcinoma characterized by spindled or pleomorphic cells which appear to be a true sarcoma but are actually of epithelial origin. Recent studies have shown that certain variants of head and neck squamous cell carcinoma are human papillomavirus (HPV) -related and are associated with more favorable outcomes. The purpose of this study was to determine the prevalence of HPV in SpCC and to explore the effect of HPV status on patient outcomes.
Design: Cases with a diagnosis of SpCC, sarcomatoid carcinoma, or SCC with a spindle cell component were retrieved from pathology department files. The diagnosis required a biphasic lesion with a clearly recognizable squamous neoplastic component or alternatively a pure spindle cell or pleomorphic tumor with documented immunohistochemical positivity for epithelial cell markers. The presence of transcriptionally-active HPV was determined by p16 immunohistochemistry and both DNA and RNA in situ hybridization (ISH) for high risk HPV E6 and E7 transcripts. We also reviewed the medical records and follow up information for all patients.
Results: Of 32 cases, 5 (15.6%) were from the oropharynx, 12 (37.5%) from the oral cavity, 1 (3.1%) from the maxillary sinus, and 14 (43.8%) from the larynx or hypopharynx. The average stage at presentation of patients with oropharyngeal SpCC was higher when compared to other sites but there were too few patients to determine statistical significance. None of the oropharyngeal SpCCs were positive for p16 or for high risk HPV by DNA or RNA ISH. Only one of the 27 non-oropharyngeal SpCC (oral cavity) was HPV positive by both DNA and RNA ISH. It also stained for p16. Another SpCC from the larynx was HPV positive by both DNA and RNA ISH in both components, but it did not stain for p16. A third case from the maxillary sinus was positive for p16 in the conventional SCC component but negative for HPV by ISH. Both HPV positive patients presented at high stage (IV), and they died with disease at 22 and 9 months after diagnosis, respectively.
Conclusions: The majority of SpCCs of the head and neck, including the oropharynx, are not HPV related, and for the rare HPV-related cases, the presence of HPV does not appear to provide any prognostic benefit, although the number of cases is insufficient to make any definitive conclusions.
Category: Head & Neck

Wednesday, March 21, 2012 9:30 AM

Poster Session V # 168, Wednesday Morning

 

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