Hypopharyngeal cancer.

Hypopharyngeal cancers are usually squamous cell carcinomas (SCCs) that has the worst prognosis among the head and neck cancers. Overall, 5-year survival rate remains poor despite recent improvements in diagnostic imaging, radiation and chemotherapy, and improved surgical techniques. Hypopharyngeal cancers tend to present with advanced primary disease, and nodal metastasis is highly likely. The most important features determining prognosis are the size and extent of local spread of the primary carcinoma and the extent of involvement of regional lymph nodes. Distant metastasis at presentation is more common in hypopharyngeal cancers than in other head and neck cancers. Poor survival rate is partly due to emergence of second primary cancers but also to development of distant metastasis. Contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) remain the mainstay of initial radiological evaluation of hypopharyngeal cancer. Imaging usually results in upstaging of the tumor at presentation. Meticulous evaluation of the extent of the primary tumor with attention to spread to the subsites of the hypopharynx, larynx, and cartilage invasion are necessary for accurate staging. After surgery and radiation therapy, it is difficult with CT and MR to differentiate residual and recurrent tumor from edema and scarring. Fluorine 18-fluoro-deoxy-glucose -positron emission tomography (FDG-PET) has high sensitivity in detection of occult, residual, and recurrent tumors but has low specificity. Combined PET and CT increase specificity and are increasingly being used to image posttreatment cases. Other newer imaging modalities such as diffusion-weighted imaging (DWI), MR spectroscopy, and MRI with superparamagnetic iron oxide (SPIO) contrast agent are reported to be useful and should be used more widely in difficult cases.