Background: Malignant neoplasms (MNs) in the head and neck are occasionally hidden in deep neck infections (DNIs) that require emergency treatment, which potentially leads to delayed diagnosis of MNs.Objectives: This study aimed to identify predictive factors that can prevent delays in diagnosing MNs in patients with DNIs.Methods: We retrospectively analysed data from 83 patients admitted to our hospital who were diagnosed with DNIs.Results: Four patients (4.8%) had DNIs veiling MNs in the head and neck. Statistical analyses revealed a significant association (p = .0481) of platelet to albumin ratio (PAR; ≥ 98.9 × 103) with hidden MNs in DNIs. Furthermore, concomitant cervical lymphadenopathy, especially multiple lymphadenopathies and excluding abscesses, was higher in patients with DNIs veiling MNs (p = .0142 and p = .0023, respectively).Conclusions and Significance: The PAR, which can be easily measured and readily detected, was a potential predictive factor. Moreover, performing fine-needle aspiration for lymphadenopathies could help diagnose hidden MNs in DNIs.