 |
Vol.63 No.4 contents | Japanese/English |
 | Full Text of PDF (2630K) Article in Japanese |
- Case Report -
A Case of Occult Prostate Cancer with Low Serum Prostate-specific Antigen That Was Diagnosed by Lung Biopsy
Yuji Nomata1, Kumiko Hashimoto1, Kunio Narita1, Yoshifumi Arai2, Matsuyoshi Maeda21Department of Respiratory Surgery, 2Department of Diagnostic Pathology, Toyohashi Municipal Hospital, Japan
Background. Lung metastasis of prostate cancer is rarely encountered in the clinical setting. It accounts for approximately 5-8% of cases of metastatic prostate cancer. Prostate-specific antigen (PSA) is a sensitive tumor marker for prostate cancer, and with PSA positivity detected in approximately 90% of patients with metastasis. Case. A 72-year-old man presented with double solid nodular shadows with clear borders in the right upper and lower lobes measuring 13 mm and 17 mm, respectively. 18F-FDG PET/CT was performed to search for primary lesions, but accumulation in other organs suggested that there was no primary lesion, and some serum tumor markers were within normal ranges. Therefore, the nodules were determined to be an inflammatory response. A year later, the patient was referred to the department of respiratory surgery due to the enlargement of existing nodules and the development of new nodules. He underwent lung biopsy, and the nodules were determined to be adenocarcinoma. Immunostaining was positive for PSA and androgen receptors, suggesting lung metastasis from prostate cancer. Prostate biopsy was performed, and the patient was diagnosed with prostate cancer. Conclusion. This case of occult prostate cancer was diagnosed by lung biopsy with low serum PSA, and no accumulation in the prostate on 18F-FDG PET/CT. Although prostate cancer was discovered through lung metastasis is rare, the proportion of elderly men with prostate cancer is high, so this should be considered as a possible primary lesion for metastatic lung tumors in elderly men.
key words: Prostate cancer, Lung metastasis, Serum prostate-specific antigen
Received: December 13, 2022
Accepted: April 6, 2023
JJLC 63 (4): 308-313, 2023
