A case of synchronous multiple primary lung cancer combining three different histological types

Multiple primary lung cancer is a very rare type of tumour that occurs when two or more primary malignant tumours develop simultaneously or sequentially in the same patient's lungs. When two or more primary sites are present at the same time, it is called synchronous multiple primary lung cancer. Currently, the pathogenesis, clinical features, and prognostic factors of synchronous multiple primary lung cancer are unclear, and there are no guidelines for diagnosis and treatment. We present a 74-year-old male patient with a combination of three histological types of synchronous primary lung cancer. He underwent partial lobectomy and was diagnosed with synchronous multiple primary lung cancer. The pathological diagnosis revealed adenosquamous carcinoma in the right lower lobe and small-cell lung cancer in the left lower lobe. After comprehensive treatment, the patient is currently stable and is under follow-up. Refining the diagnosis and treatment of multiple primary lung cancers remains challenging. Our case and case studies in the literature may provide some ideas for more standardized diagnosis and treatment.