Cancer of unknown primary eventually diagnosed as poorly differentiated prostate cancer: a case report

Abstract

Background: Prostate cancer has been well known to have a high prevalence among middle-aged and older men, with high incidence of metastases to the bone-the main metastatic site. However, prostate cancer among those less than 50 years of age is extremely rare, and neck swelling is seldom the initial symptom.

Case presentation: We herein report case of a 47-year-old Japanese male with poorly differentiated prostate cancer that had been initially diagnosed as a cancer of unknown primary with multiple lymph node and bone metastases before reaching a definitive diagnosis. The patient has been started on endocrine therapy and is currently alive without progression.

Discussion and conclusion: When locating the primary lesion in men with cancer of unknown primary, it is important to consider the possibility of prostate cancer, confirm serum prostate-specific antigen levels, and perform local prostate evaluation.

Keywords: Bone metastases; Cancer of unknown primary; Cervical lymph node metastases; Positron emission tomography/computed tomography; Prostate cancer; Prostate-specific antigen.