A recommendation for the management of lesions of unknown malignancy in multiple primary malignant neoplasm patients: A case report

In numerous patients with multiple primary malignant neoplasms, it is difficult to determine whether the mass is benign or malignant, and the method to treat these lesions is controversial. For patients with a history of cancer, a point of high-risk for the development of a second primary tumor occurs following a 10-year gap. To the best of our knowledge, to date, there has been no large clinical trial to observe the appropriate method to manage the lesions in patients with multiple primary malignant neoplasms. The present study reports the case of a patient who was initially diagnosed with rectal cancer, treated with Dixon's rectectomy and post-operative chemotherapy. The patient's disease was evaluated as complete response following these treatments. However, the patient then presented with bladder cancer and underwent transurethral resection of the bladder tumor, again achieving a complete response. The patient more recently presented with hepatocellular carcinoma, which developed from an unexplained mass in the liver. The patient underwent partial liver resection and to date, has achieved a complete response. The management of masses of unknown malignancy is also discussed. The current case provides useful insight for future research in this field.