Culture-positive neck abscess masking metastatic squamous cell carcinoma: a diagnostic pitfall

A man in his 40s presented with progressive tongue swelling and imaging findings of a right-sided deep neck fluid collection concerning for abscess. Despite empiric treatment with antibiotics and corticosteroids, there was no clinical improvement. Incision and drainage yielded purulent material and cultures grew Cutibacterium acnes, initially supporting an infectious aetiology. However, histopathological evaluation revealed metastatic keratinising squamous cell carcinoma involving lymph node tissue.Immunohistochemistry showed p40 positivity and p16 negativity, supporting a human papillomavirus-unrelated squamous cell carcinoma. Because of the patient's poor functional status, further oncological investigation was not pursued and palliative management was initiated.This case highlights a diagnostic pitfall in which metastatic squamous cell carcinoma may coexist with a culture-positive deep neck abscess. Positive bacterial cultures do not exclude underlying malignancy, and histopathological evaluation of tissue obtained during drainage remains essential, particularly in adult patients with atypical clinical presentations.