Atypical Presentation of Seminoma in the Prostate - Case Report

Diagnosis and treatment of primary seminoma of the prostate: A case report and review of literature

BACKGROUND

Primary seminoma of the prostate (PSP) is a rare type of extragonadal germ cell tumour that is easily misdiagnosed, owing to the lack of specific clinical features. It is therefore necessary for clinicians to work toward improving the accuracy of PSP diagnosis.

CASE SUMMARY

A 59-year-old male patient presenting with acute urinary retention was admitted to a local hospital. A misdiagnosis of benign prostatic hyperplasia led to an improper prostatectomy. Histopathology revealed PSP invading the bladder neck and bilateral seminal vesicles. Further radiotherapy treatment for the local lesion was performed, and the patient had a disease-free survival period of 96 mo. This case was analysed along with 13 other cases of PSP identified from the literature. Only four of the cases (28.6%) were initially confirmed by prostate biopsy. In these cases, imaging examinations showed an enlarged prostate (range 6-11 cm) involving the bladder neck (13/14). Of the 14 total cases, 11 (78.6%) presented typical pure seminoma cell features, staining strongly positive for placental alkaline phosphatase, CD117, and OCT4. The median age at diagnosis was 51 (range 27-59) years, and patients had a median progression-free survival time of 48 (range 6-156) mo after treatment by cisplatin-based chemotherapy combined with surgery or radiotherapy. The remaining three were cases of mixed embryonal tumours with focal seminoma, which had clinical features similar to those of pure PSP, in addition that they also had elevated serum alpha-fetoprotein, beta-human chorionic gonadotropin, and lactose dehydrogenase.

CONCLUSION

PSP should be considered in patients younger than 60 years with an enlarged prostate invading the bladder neck. Further prostate biopsies may aid in proper PSP diagnosis. Cisplatin-based chemotherapy is still the main primary therapy for PSP.

Radiotherapy as a Single Modality in Primary Seminoma of the Prostate

Extragonadal germ cell tumors (EGCTs) are uncommon, and those involving the prostate are rare. We report on a primary seminoma of the prostate in a 56-year-old male presenting with scrotal pain, urinary frequency and urgency, and erectile dysfunction. Digital rectal examination revealed a hard, markedly enlarged prostate projecting posteriorly into the rectum. All 12 cores from ultrasound-guided prostate biopsy revealed malignant cells that stained positive for OCT4, PLAP, and CD117. Imaging revealed a 10.2 cm x 7.8 cm x 8.4 cm prostate mass with irregular nodular margins extending superiorly to the base of the bladder and posteriorly abutting the anterior rectal wall. There was no evidence of distant metastatic disease on both nuclear medicine and CT scans of the chest, abdomen, and pelvis. An 11 mm right internal iliac lymph node and several tiny sub-centimeter external iliac nodes were noted bilaterally. The patient was treated with radiotherapy to the prostate and pelvic lymph nodes. The pelvic lymph nodes were treated with 20 Gy in eight fractions, followed by a boost to the prostate for a further 20 Gy in eight fractions. There was a significant response during treatment that allowed an adaptive boost for a further 10 Gy in four fractions to bring the total dose to the prostate to 50 Gy in 20 fractions. Treatment was well tolerated. Adjuvant chemotherapy was not recommended. He remains disease-free 24 months post-treatment. This case report indicates that like most seminomas, extragonadal seminomas are exquisitely sensitive to radiotherapy and may be considered for the primary treatment of non-metastatic disease. To our knowledge, this is the first reported case of the sole use of radiotherapy to treat a primary seminoma of the prostate.