Cytological Diagnosis of a Rare Case of Buccal Mucosa Squamous Cell Carcinoma with Malignant Pleural Effusion and Review of Literature

Oral squamous cell carcinoma (OSCC) is a major global health concern, especially in India, where it is one of the primary causes of cancer-related fatalities. OSCC is notorious for its propensity to spread to distal sites such as the lungs, bones, and liver, but malignant pleural effusions resulting from OSCC are extremely uncommon. This case report details an unusual presentation of OSCC in a 61-year-old male presenting with bilateral malignant pleural effusion from a primary buccal mucosa squamous cell carcinoma with no lung involvement. Through cytological analysis and immunocytochemistry, we confirm the diagnosis of metastatic squamous cell carcinoma, highlighting the significance of comprehensive diagnostic approaches.