We report the case of a 68-year-old man with a stromal tumor of uncertain malignant potential (STUMP), which had metastasized to the lung. The patient complained of an enlarged mass in the anterior chest. Chest computed tomography (CT) showed a sternal abscess with multiple nodules in both lungs. A thoracoscopic lung biopsy of the nodules and incision/drainage of the sternal mass were performed simultaneously. CT of the pelvis revealed an enlarged prostate with irregular cystic lesions in the pelvis. Prostate biopsy was done and demonstrated hypercellular stroma with minimal cytological atypia, a distinct pattern of STUMP. The sternal abscess proved to be tuberculosis and the lung lesion was consistent with STUMP, which had spread from the prostate. However, to our knowledge, the tuberculous abscess might not be assoicated with STUMP in the lung. The patient refused surgical prostatectomy and was discharged with anti-tuberculosis medication. On one-year follow up, the patient had no evidence of disease progression.