Primary pituitary gland cancer is extremely rare. The current study presents the case of a patient diagnosed with pituitary cancer three months after completing surgery and post-operative chemoradiotherapy for hypopharyngeal cancer. In this report we discuss 57-year-old patient who presented with diplopia and ptosis four months following the completion of treatment for hypopharyngeal cancer. A poorly-differentiated pituitary carcinoma was located. Despite aggressive treatment and surgical excision with postoperative chemoradiotherapy, the disease progressed rapidly and the patient succumbed due to multiple metastases and organ failure. This case report indicates a possible correlation between irradiation and the development of pituitary cancer.