A case of metastatic cancer with markedly elevated PSA level that was not detected by repeat prostate biopsy.
BACKGROUND
Prostate-specific antigen (PSA) is a widely used specific tumor marker for prostate cancer. We experienced a case of metastatic prostate cancer that was difficult to detect by repeat prostate biopsy despite a markedly elevated serum PSA level.


METHODS
A 64-year-old man was referred to our hospital with lumbar back pain and an elevated serum PSA level of 2036 ng/mL. Computed tomography, bone scintigraphy, and magnetic resonance imaging showed systemic lymph node and osteoblastic bone metastases. Digital rectal examination revealed a small, soft prostate without nodules. Ten-core transrectal prostate biopsy yielded negative results. Androgen deprivation therapy (ADT) was started because of the patient's severe symptoms. Twelve-core repeat transrectal prostate biopsy performed 2 months later, and transurethral resection biopsy performed 5 months later, both yielded negative results. The patient refused further cancer screening because ADT effectively relieved his symptoms. His PSA level initially decreased to 4.8 ng/mL, but he developed castration-resistant prostate cancer 7 months after starting ADT. He died 21 months after the initial prostate biopsy from disseminated intravascular coagulation.


CONCLUSIONS
CUP remains a considerable challenge in clinical oncology. Biopsies of metastatic lesions and multimodal approaches were helpful in this case.
Hiromichi
H
Iwamura
Shingo
S
Hatakeyama
Yoshimi
Y
Tanaka
Toshikazu
T
Tanaka
Noriko
N
Tokui
Hayato
H
Yamamoto
Atsushi
A
Imai
Takahiro
T
Yoneyama
Yasuhiro
Y
Hashimoto
Takuya
T
Koie
Kazuaki
K
Yoshikawa
Department of Urology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Japan. cohyama@cc.hirosaki-u.ac.jp.
Chikara
C
Ohyama
D000230:Adenocarcinoma / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy / Q000473:pathology / Q000556:secondary*; D000726:Androgen Antagonists / Q000627:therapeutic use; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001416:Back Pain / Q000209:etiology; D001707:Biopsy, Needle; D001859:Bone Neoplasms / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy / Q000473:pathology / Q000556:secondary*; D003952:Diagnostic Imaging; D004211:Disseminated Intravascular Coagulation / Q000209:etiology; D000077143:Docetaxel; D019008:Drug Resistance, Neoplasm; D005188:False Negative Reactions; D017809:Fatal Outcome; D006801:Humans; D008297:Male; D008875:Middle Aged; D009376:Neoplasms, Hormone-Dependent / Q000097:blood / Q000175:diagnosis / Q000473:pathology / Q000556:secondary*; D009382:Neoplasms, Unknown Primary; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D043823:Taxoids / Q000008:administration & dosage; D020728:Transurethral Resection of Prostate
D000726:Androgen Antagonists; D018931:Antineoplastic Agents, Hormonal; D043823:Taxoids; D000077143:Docetaxel; D017430:Prostate-Specific Antigen