Heterochronous multiple primary prostate cancer and lymphoma: A case report.

BACKGROUND: Multiple primary malignant tumors (MPMTs) are rare type of cancer, especially when solid tumors are the first and lymphoma is the second primary malignancy. We report a patient with heterochronous MPMTs consisting of prostate cancer and rectal diffuse large B-cell lymphoma (DLBCL). CASE SUMMARY: We report a 77-year-old male patient diagnosed with prostate cancer who was treated with radiation therapy and one year of endocrine therapy with bicalutamide (50 mg per day) and an extended-release implant of goserelin (1/28 d). Seven years later, rectal DLBCL with lung metastases was found. CONCLUSION: Although rare, the possibility of prostate cancer combined with a double primary cancer of DLBCL can provide a deeper understanding.