Abstract
A 73-year-old male was admitted to our hospital for a left neck mass that had persisted for one month. Laboratory investigation revealed slightly elevated lactate dehydrogenase and soluble interleukin-2 receptor (IL-2r). MRI images of the neck revealed multiple neck lymph nodes swelling from the subclavicular to inferior jugular region on the left side. The lymph node of the hilum of the lung was detected by FDG-PET. We performed open biopsy of the neck lymph nodes to rule out malignant lymphoma and diagnosed this lymph node as metastatic acinic cell carcinoma. We performed additional examinations, but there was no primary site of the neck lymph nodes. We diagnosed this disease as metastatic neck lymph nodes of unknown origin and performed radical neck dissection. After the operation, we repeatedly explained the need to search for the primary site of the neck lymph nodes but the patient did not agree. Eight months after the operation, the patient finally agreed to the examination. The PAS level was high and FDG-PET revealed a hot-spot in the prostate. We diagnosed metastatic lymph nodes of prostate cancer, and so performed maximum androgen blockade therapy with LHRH agonist and Bicalutamide. After the therapy, the PSA was within normal limits.
