A 15mm nodule in the lower lobe of the right lung is considered a relatively large nodule, but it does not determine its severity, which needs to be determined in conjunction with its shape and margins.
Generally speaking, a lung nodule with a diameter of 15mm is malignant. If the nodule is regular in shape, has clear borders, and no adhesions or thickening of the surrounding pleura have occurred, it is a benign nodule and only requires a thin-layer CT examination.
If the lung nodule is irregular in shape, has blurred borders, and shows signs of pleural depression, it is mostly suggestive of malignancy and requires a lung puncture biopsy.
If the lung puncture biopsy suggests an inflammatory nodule, usually only anti-infective treatment is needed. If it is a fungal infection the nodule needs to be resected and treated with antifungal therapy, and if it is a malignant tumor it needs to be surgically resected as early as possible, along with peripheral lymph node dissection.
Therefore, when a 15-mm nodule in the lower lobe of the right lung is found on examination, lung puncture biopsy is recommended to determine the benign or malignant nature of the nodule, so as to determine the treatment plan and avoid disease progression.