Malignancies, which present as deep neck abscesses are uncommon and may result in a delayed diagnosis or potentially a misdiagnosis. The present study describes a patient who exhibited a deep neck abscess as the initial manifestation of carcinoma of unknown primary (CUP). The aim of the present study was to raise awareness of this unusual presentation of CUP and emphasize the importance of repeating targeted fine-needle aspiration cytology or biopsies in patients presenting with a deep neck abscess suspicious for malignancy.