ACRT Journal

Discussion

Pulmonary metastasis in prostate cancer typically occurs in widespread disease via hematogenous dissemination [2]. Isolated pulmonary lesions are clinical anomalies and may be misdiagnosed as primary lung cancer or benign nodules [1,3]. This patient’s nodule demonstrated low metabolic activity, further obscuring suspicion for malignancy.

Importantly, PSA-negative prostate adenocarcinoma complicates standard surveillance algorithms. PSA remains a key biomarker, but in rare cases such as this, imaging and histology are essential for accurate detection and staging [4]. The delayed onset of metastasis nearly six years after curative therapy highlights the need for long-term follow-up in high-risk patients regardless of PSA status [2]. 

Biopsy and immunohistochemistry were vital to distinguish primary lung cancer from metastatic prostate cancer-especially given the lesion’s faint FDG activity. Pathology confirmed its origin based on PSA positivity and prostate-specific morphological features [4,5]. After metastasectomy, undetectable PSA and stable clinical parameters suggested both therapeutic benefit and effective systemic control.

Treatment decisions in solitary metastasis remain nuanced. While ADT is standard for systemic recurrence, localized interventions such as surgery or stereotactic, radiotherapy may improve outcomes in select patients [6]. This case supports the integration of metastasectomy as a viable option when feasible, particularly in well-performing patients.

Conclusion

This case illustrates the rare occurrence of solitary pulmonary metastasis in a patient with high-grade, PSA-negative prostate cancer. It calls attention to the limitations of relying solely on PSA for monitoring and stresses the importance of advanced imaging and histopathological confirmation. Management of atypical metastasis requires a tailored, multidisciplinary approach-balancing systemic therapy with localized interventions. As prostate cancer follow-up extends years beyond initial therapy, clinicians must remain alert to late-stage unusual presentations. This report adds to the evolving understanding of metastatic pathways and guides future evaluation of solitary pulmonary lesions in prostate cancer survivors.

Conflict of Interest: We as authors declare that there is no conflict of interest regarding the publication of this article.

Patient Consent: Written informed consent was obtained from the patient for the publication of their clinical details and any accompanying images. The patient was informed that efforts would be made to conceal their identity, but anonymity could not be guaranteed. A signed copy of the consent form is available and can be provided to the journal upon request.

References

1. Maru N, Ishikawa T, Nakano K, Utsumi T, et al. (2021) Solitary lung metastasis from primary prostate cancer with normal PSA levels: A case report. World Academy of Sciences Journal. 3: 74-78.
2. Gee JR, Libertino JA. (2021) Multimodal therapy for high-risk prostate cancer with long-term follow-up. Int J Clin Oncol. 6: 125-129.
3. Gemalmaz H, Gunaydin O, Demirci M, Çulhac N, et al. (2021) Isolated pulmonary metastasis metastasectomy after curative prostate cancer treatment. Bulletin of Urooncology. 20: 270-272.
4. Shindo K, Fujimoto K, Akiyama Y, Moriyama T, et al. (2020) A rare case of PSA-negative metastasized prostate cancer to the stomach. Surgical Case Reports. 6: 234.
5. Bratt O, Auvinen A, Godtman RA, Hellström M, Hugosson J, et al. (2023) Screening for prostate cancer: evidence and knowledge gaps. BMJ Oncology. 2: e000142.
6. Watanabe K, Taira AV, Lin Y, Ikeda N, et al. (2025) Long-term outcomes of salvage HDR brachytherapy for prostate cancer recurrence. BMC Cancer. 25: 317.