Solitary lung metastasis after radical prostatectomy in presence of undetectable PSA.

Clinical recurrence in the absence of biochemical PSA failure is uncommon and accounts for less than 1%; we report a rare case of solitary lung metastasis in a patient with undetectable PSA level (<0.1 ng/mL) after radical prostatectomy (RP) for prostate cancer (PCa). An asymptomatic 75-year-old man nine years after RP showed a solitary lung mass (about 2 cm) at chest radiography; the 18-FDG-PET/CT confirmed the presence of an isolated mass suspicious for primitive pulmonary cancer. The initial histological specimen after RP showed a mixed acinar and ductal PCa (Gleason score 7, pT3aNO stage, negative surgical margins). A segmental pulmonary resection was performed and definitive specimen demonstrated a single ductal PCa metastasis; after six months from surgery the patient was free from recurrence. In conclusion, in patients with atypical PCa variants imaging studies may be considered in the follow up even in presence of undetectable PSA because they could benefit from early salvage therapy.