Accurate delineation of the target area for patients with hypopharyngeal cancer is the key to achieving an ideal radiotherapy effect. Since computed tomography (CT) alone can no longer meet the treatment needs, fusing CT images with magnetic resonance imaging (MRI) or positron emission tomography (PET) images can overcome the disadvantages of CT. Herein, we present a clinical case of hypopharyngeal cancer to delineate the tumor volume using combined MRI-CT and PET-CT fusion images to examine if they could accurately cover the tumor volume.A 67-year-old male patient with hypopharyngeal carcinoma could not tolerate chemotherapy and surgery due to complicated health issues such as diabetic nephropathy and other underlying diseases. After multidisciplinary consultations, clinicians eventually agreed to undergo radiotherapy to control the progression of his tumor. He was examined by CT, MRI, and 18-fluorodeoxyglucose-PET for treatment planning, and CT images were fused with PET and MRI images while delineating tumor volume.The image fusion of MRI-CT and PET-CT has both advantages and disadvantages. Compared with CT images alone, the combination of MRI-CT and PET-CT fusion images can precisely cover the gross tumor volume in hypopharyngeal carcinoma and avoid overestimation or incomplete coverage of tumor volume.©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.