p16 Immunohistochemistry Is a Useful Diagnostic Adjunct in Cases of Metastatic Cervical Carcinoma of Unknown Origin.
OBJECTIVE
Metastatic cervical carcinoma of unknown primary (MCCUP) is increasing in frequency owing in part to rising human papillomavirus (HPV)-driven oropharyngeal carcinoma. Identifying the primary site is valuable, because it is associated with increased survival and decreased morbidity. HPV-positive cervical nodal disease focuses attention on the oropharynx for directed biopsy examinations, including tonsillectomy. When the primary is small, carcinoma might not be apparent by traditional hematoxylin and eosin (H&E) staining alone.


METHODS
This report describes 2 cases of p16-positive MCCUP in which a small primary carcinoma was not readily identified in surgical specimens using H&E staining.


RESULTS
Additional evaluation of the specimens with p16 immunohistochemistry (IHC) showed carcinoma in these 2 cases.


CONCLUSIONS
When H&E staining does not show carcinoma in cases of MCCUP, p16 IHC should be considered given the high prevalence of HPV-positive MCCUP and the potential for identification of a small primary tumor that might otherwise be missed with H&E staining.
Resident, Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI. Electronic address: MRohrbach@uwhealth.org.
Marc R
MR
Rohrbach
Resident, Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI.
Christopher J
CJ
Britt
Resident, Department of Pathology and Laboratory Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI.
Michael
M
Schwalbe
Assistant Professor, Section of Head and Neck Surgical Oncology, Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI.
Aaron M
AM
Wieland
Chief, Section of Head and Neck Surgical Oncology, Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI.
Gregory K
GK
Hartig
D014408:Biomarkers, Tumor / Q000032:analysis; D001706:Biopsy; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000032:analysis*; D003937:Diagnosis, Differential; D003952:Diagnostic Imaging; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D008297:Male; D008875:Middle Aged; D037981:Neck Dissection; D009382:Neoplasms, Unknown Primary / Q000473:pathology*; D009959:Oropharyngeal Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D014068:Tonsillectomy
D014408:Biomarkers, Tumor; D019941:Cyclin-Dependent Kinase Inhibitor p16