A case of prostatic metastasis from non‐seminomatous testicular cancer

Abstract

Introduction

Prostatic metastasis from testicular cancer is extremely rare, with only 10 reported cases, all of which were diagnosed as relapse. Herein, we report the case of a patient with concurrent testicular cancer and prostatic metastasis.

Case presentation

A 57‐year‐old man presented at our emergency department with urinary retention. A painless mass was found in the right scrotum, and computed tomography showed lung, mediastinal, and liver metastases, and an enlarged prostate. Tumor markers were measured in 2057 U/L lactate dehydrogenase, 2460 mIU/mL human chorionic gonadotrophin, 1303 ng/mL alpha‐fetoprotein, and 1.51 ng/mL prostate specific antigen. An orchiectomy and biopsy were performed; the pathological results showed immature teratomas, embryonal carcinomas, choriocarcinomas, and seminomas in the testis, and embryonal carcinomas in the prostate, liver, and mediastinum. The patient refused chemotherapy and died 3 months following diagnosis.

Conclusion

Prostatic metastasis should be considered in cases of dysuria or prostate enlargement in testicular cancers.

Keynote message.

Prostatic metastasis from testicular cancer is extremely rare and is diagnosed as relapse in most cases. Prostate metastasis should be considered when a patient with a history of testicular cancer experiences dysuria or has an enlarged prostate on imaging.

Abbreviations & Acronyms

DWI

diffusion‐weighted image

PSA

prostate‐specific antigen

T2WI

T2‐weighted image

Introduction

Metastases are diagnosed in approximately 30% of testicular cancers, and the sites of metastases are commonly the lungs (61.9%), distant lymph nodes (36.2%), liver (15.2%), bones (6.7%), and brain (6.4%). ¹ Testicular cancer metastasis to the prostate is extremely rare. Only 10 cases have been reported to date, and all cases were diagnosed as relapses.

We report the case of a patient who presented with urinary retention due to a blood clot and was subsequently diagnosed with concurrent testicular cancer and prostatic metastasis. To the best of our knowledge, this is the first report of a case of non‐seminomatous testicular cancer metastasis to the prostate at the initial diagnosis.

Case presentation

A 57‐year‐old man presented at the emergency department with urinary retention, painless right scrotal swelling for 3 months, and dysuria and gross hematuria for 2 weeks. On physical examination, a 10‐cm painless mass was found in the right scrotum, and a digital rectal examination revealed a stony hard prostate. Ultrasonography revealed a clot in the bladder, an enlarged prostate, and a solid tumor in the right testis. Tumor marker levels were measured at 2057 U/L lactate dehydrogenase, 2460 mIU/mL human chorionic gonadotrophin, 1303 ng/mL alpha‐fetoprotein, and 1.51 ng/mL PSA. Contrast‐enhanced computed tomography revealed a right testicular tumor, multiple lung metastases, mediastinal metastasis, multiple liver metastases, and an enlarged prostate (Fig. 1). Magnetic resonance imaging indicated a right testicular tumor and prostate cancer (Fig. 2). Double metastatic testicular cancer and prostate cancer (e.g., high‐grade undifferentiated prostate cancer or neuroendocrine tumor cases where the PSA level does not increase) were suspected. Right high inguinal orchiectomy, transrectal prostate biopsy, percutaneous liver biopsy, and transthoracic mediastinal biopsy were also performed. Pathological results showed immature teratoma, embryonal carcinoma, choriocarcinoma, and seminoma in the right testis, and embryonal carcinoma in the prostate, liver, and mediastinal biopsies. The embryonal carcinoma components of each metastatic lesion were placental alkaline phosphatase‐positive, octamer binding transcription factor 3/4‐positive, CD30‐positive, alpha‐fetoprotein‐negative, CD117 (c‐kit)‐negative, and human chorionic gonadotropin‐negative (Fig. 3). The diagnosis was non‐seminomatous testicular cancer (pT2N0M1bS2). We strongly suggested immediate systemic chemotherapy for metastatic testicular cancer, however, the patient refused. While it was explained that chemotherapy for testicular cancer could achieve complete remission, the patient refused any treatment and selected supportive care instead. Figure 4 shows changes in the tumor markers and image findings from the first visit. The tumor marker level decreased once after high inguinal orchiectomy but gradually increased. Computed tomography showed no new lesions, but liver and mediastinal metastases were remarkably enlarged. The patient complained of abdominal distension and abdominal pain, and received palliative care such as opioid treatment as an outpatient. Three months after the diagnosis, he was urgently hospitalized because of dyspnea and a poor general condition, and renal and hepatic function were remarkably deteriorated. The patient died of cancer 3 months after the initial diagnosis.

Fig. 1.

Contrast‐enhanced computed tomography revealed a 10‐cm primary mass in the right testis (a) and multiple metastasis in the mediastinum (b), liver (c), and enlarged prostate (d).

Fig. 2.

Pelvic magnetic resonance imaging revealed a 7‐cm enlarged prostate, protruding into the bladder: (a) T2WI, (b) DWI, as well as a right testicular tumor: (c) T2WI and (d) DWI.

Fig. 3.

The pathological results of the right high inguinal orchiectomy. (a) The pathology identified areas of immature teratoma (yellow arrow), embryonal carcinoma (black arrow), choriocarcinoma, and seminoma in the testis (hematoxylin and eosin staining, magnification 10×). (b)Enlargement of the components of embryonal cancer (hematoxylin and eosin staining, magnification 20×). (c) Immunostaining of CD30 was positive in the components of embryonal cancer. (d) The pathological results of the prostate biopsy. Immunohistochemistry was positive for CD30, indicating prostatic metastasis from testicular cancer, whose component is embryonal carcinoma.

Fig. 4.

Changes in the tumor markers and image findings from the first visit.

Discussion

We report a case of metastatic non‐seminomatous testicular cancer that presented with symptoms of prostate metastasis at the first visit. Based on the patient's age and imaging findings, both testicular and prostate cancer were suspected. Following biopsy, however, the patient was diagnosed with metastasis of non‐seminomatous testicular cancer to the prostate. To the best of our knowledge, this is the first case of prostatic metastasis from testicular cancer at initial diagnosis.

Distant lymph nodes (36.2%) and the liver (15.2%) are common sites of testicular cancer metastasis. ¹ However, we performed percutaneous liver and mediastinal biopsies. Regarding the prostate lesions, we suspected high‐grade undifferentiated adenocarcinoma or neuroendocrine tumors because the PSA level was not elevated relative to the digital rectal examination and imaging findings. Liver metastases are often observed in de novo neuroendocrine tumors (74.5%), ² so we determined that a histological diagnosis of the liver tumors was necessary and performed a percutaneous liver biopsy. Regarding the mediastinal lesion, we decided to perform a biopsy in consideration of residual tumor resection after chemotherapy. In this case, there was no regional lymph node metastasis, and the lung metastasis was as small (approximately 15 mm at maximum) and was expected to disappear completely after chemotherapy. In metastasectomy to evaluate whether viable cancer cells remain, the least invasive lesion was considered to be the mediastinum. A percutaneous mediastinal biopsy was performed to clarify whether the histology of the mediastinal lesion was testicular cancer or prostate cancer. Consequently, all lesions were metastases from testicular cancer. The biopsy results would have been useful in deciding treatment strategies and in resecting residual tumors after chemotherapy. Unfortunately, the patient refused treatment, but the percutaneous liver and mediastinal biopsies were invasive.

To date, 10 cases of prostatic metastasis from testicular cancer have been reported. ² , ³ , ⁴ , ⁵ , ⁶ , ⁷ , ⁸ , ⁹ , ¹⁰ , ¹¹ The pathological findings of the primary testicular lesions were seminoma and non‐seminoma in seven and three cases, respectively. All 10 were cases of relapse. The mean age at relapse was 44 years (range: 28–69 years) and the patients were diagnosed with dysuria and prostate enlargement following imaging. In contrast, eight cases of extragonadal germ cell carcinoma originating from the prostate have been reported. ¹² Histologically, seven were seminoma and one was non‐seminoma, with a mean age at diagnosis of 42 years (range: 27–58 years). In this case, there are two reasons why we diagnosed prostatic metastasis from testicular cancer rather than from primary prostate carcinoma: First, painless swelling of the scrotum preceded dysuria and gross hematuria. Second, the testes had multiple histological types, but the prostate showed a single histological type similar to that of the liver and mediastinum.

The mechanism by which testicular cancer metastasizes to the prostate is still controversial. Torelli stated that hematogenous metastasis is unlikely because no cases of visceral metastasis have been reported. Rather, metastasis from the testis to the prostate is caused by local anatomic alterations and inverted lymph flow from metastatic pelvic nodes. ⁸ Sagalowsky stated that the tumor can spread along the spermatic cord. ³ In which case, considering that there was no metastasis to the lymph nodes or spread to the spermatic cord and that the metastasis was in the lung, liver, and mediastinum, it was clearly hematogenous from the testis to the prostate.

Complete remission has been achieved with cisplatin‐based systemic chemotherapy in nine cases of prostatic metastasis. Although the number of cases was small, chemotherapy appears to be effective against prostatic metastasis from testicular cancer.

Conclusions

Ten cases of prostatic metastasis from testicular cancer have been previously reported as relapses. Here, we report the first case of prostatic metastasis from non‐seminomatous testicular cancer at the initial diagnosis. If dysuria or prostate enlargement on imaging occurs in testicular cancer, a rare case of testicular metastasis should be considered.

Author contributions

Taisho Noda: Writing – original draft. Akira Fujisaki: Writing – review and editing. Kosuke Uchida: Validation. Heisuke Iijima: Validation. Yasuhiro Hakamata: Validation. Yuka Kanda: Validation. Shin Imai: Validation. Yoshiro Otsuki: Validation. Tatsuaki Yoneda: Supervision.

Conflict of interest statement

The authors declare no conflict of interest.

Approval of the research protocol by an Institutional Reviewer Board

Not applicable.

Informed consent

Written informed consent was obtained.

Registry and the Registration No. of the study/trial

Not applicable.