Solitary lung metastasis from primary prostate cancer with normal prostate specific antigen levels: A case report and literature review

Abstract

Pulmonary involvement from prostate cancer is a well‑known condition; however, solitary lung metastasis is rare, with its associated clinical characteristics not yet fully elucidated. The present study describes the case of a 77‑year‑old male, who had undergone radical prostatectomy at a previous hospital for primary prostatic carcinoma 14 years prior, who presented with a low‑grade fever. At the previous hospital, salvage radiation therapy was being considered, as the prostate‑specific antigen (PSA) level had gradually increased within the normal range. Computed tomography performed at the authors' institution revealed a solitary nodule with a spiculated morphology located on the upper lobe of the left lung, while positron emission tomography suggested malignancy without metastasis. Based on these findings, primary lung cancer was suspected and thoracoscopic left upper lobectomy with lymph node dissection was performed. The pathological diagnosis of the tumor was a solitary lung metastasis of prostate cancer. The post‑operative recovery was uneventful. In addition to reporting a case with normal PSA levels, the present study also performed a literature review. According to previous case reports, there are some pitfalls of prostate cancer leading to misdiagnosis as a primary lung tumor. However, it is considered that surgical resection is associated with an increased diagnostic accuracy and long‑term survival.