A rare case of pleomorphic adenoma with difficult diagnosis using biopsy.

An 85-year-old woman was found to have a nodule in the left S6 of the lung on computed tomography (CT); the pathological diagnosis from the CT-guided biopsy was adenoid cystic carcinoma. We accordingly performed left lower lobectomy. Pathologically, the biphasic cell population showed admixtures in varying proportions of epithelial and stromal elements, thereby indicating pleomorphic adenoma (PA). PA of the lung is extremely rare with reports of only 20 patients so far. Interestingly, this case was difficult to diagnose using CT-guided biopsy because the overview and biphasic cell population obtained on biopsy were garbled. Here we have reported our rare experience of PA.