Abstract
Here, we present a unique case involving a female patient in her 40s with synchronous malignant pleural and peritoneal mesothelioma, despite lacking a history of asbestos exposure. The patient's initial symptoms included dyspnoea, chest pain, cough, fever, appetite loss, and weight loss over a month. Clinical evaluation led to the identification of right-sided pleural effusion, prompting consideration of differential diagnoses, such as tubercular or malignant pleural effusion. A thoracoscopy-guided biopsy, followed by histopathological examination and immunohistochemical staining, confirmed the diagnosis of mesothelioma. Chemotherapy was initiated as part of the treatment plan. The prognosis for this condition is generally bad; however, unusual cases of extended survival have been documented. The complexities of our case underscore the critical necessity for a thorough and aggressive evaluation of pleural effusion cases to unveil rare underlying causes, such as mesothelioma.