PSBL is a rare disease that can be challenging to differentiate from prostate cancer and other primary seminal vesicle tumors in clinical practice. Primary seminal vesicle carcinoma is relatively uncommon and is often invaded by carcinomas arising in nearby structures, such as the prostate, bladder, and rectum, which can complicate the differential diagnosis [6]. Early diagnosis of seminal vesicle carcinoma is often challenging due to the lack of immunohistochemical markers that distinguish it from invasive adenocarcinoma of adjacent organs [7].

Initially, we suspected prostate cancer in the 49-year-old male patient in this case, who was later diagnosed with BL. DRE suggested primary lymphoma in the prostate invading seminal vesicle. Other studies reported that DRE findings of prostate hyperplasia, hard consistency, and disappearance of the central fissure, or nodules in some patients are similar to primary prostate cancer [8, 9]. In our case, DRE suggested prostate hyperplasia, disappearance of the central fissure, and hard consistency without tenderness, raising concerns about prostate cancer. An overview of large patient samples showed that serum PSA was within 4 ng/ml [9]. The PSA test remains the only biomarker for detecting and monitoring prostate cancer [10]. Currently, PSA > 3 ng/ml, positive MRI prostate imaging shows the highest detection of prostate cancer [11]. These clinical features indicate prostate cancer, and a biopsy of the prostate was performed. However, we did not obtain the seminal vesicle pathology, which may be related to local anesthesia and insufficient understanding of the probability of primary seminal vesicle carcinoma. MRI/ultrasound combination can improve the positive rate of seminal vesicle invasion biopsy [12, 13]. The missed case emphasizes the need to improve biopsy accuracy. Cysto-prostato-seminal vesiculectomy with pelvic lymph node dissection should be adopted as the standard surgical approach for malignant tumors of seminal vesicle origin. However, as this condition is very rare, there is no standard treatment approach, and the outcomes are uncertain [14]. Partial resection of the seminal vesicles with postoperative adjuvant therapy has also been reported for the comprehensive treatment of primary tumors of the seminal vesicles [15].

The final diagnosis of BL has rarely been reported. In general, HIV-associated lymphomas are characterized by greater extranodal involvement than those found in patients who are negative for HIV. As in endemic and sporadic BL, the translocation of the MYC gene on chromosome 8 is present in almost 100% of BL cases associated with HIV. HIV-associated BL shares many histological features, such as positive CD20, CD10, and Ki-67 [2]. The histological features of the present case were similar to standard HIV-associated BL.

The commonly used treatment for BL is similar to that for other forms of lymphoma, and it mainly includes chemotherapy, radiotherapy, combined chemoradiotherapy, and resection of the tumor to relieve the local symptoms [1, 2]. Dunleavy and colleagues [16] reported that less toxic chemotherapy regimens (etoposide, doxorubicin, vincristine, cyclophosphamide, prednisone, and rituximab, DA-EPOCH-R), used at higher intensities than standard chemotherapy regimen of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP), achieved higher response rates and overall survival in PLWH. The negative biopsy result reinforced our suspicion of prostate cancer, so we performed radical resection. It is generally recognized that the prognosis of BL is relatively poor [2]. Galicier [17] conducted a study on 63 PLWH with advanced disease who were treated with the LMB 86 regimen (escalated cyclophosphamide, doxorubicin, vincristine, and prednisolone and consolidation with cytarabine and etoposide), and found that the complete response rate was 70%, whereas 2-year overall survival was 47%. Rituximab has a vital role in BL treatment. Previous studies have shown that 10–30% dose adjustments may be necessary for CHOP-like chemotherapy regimens in patients with renal dysfunction and dialysis [18]. Inotuzumab ozogamicin and Brentuximab vedotin have potential as future treatment approaches. The emergence of immune checkpoint inhibitors may lead to better overall response rates, and using pembrolizumab in combination with R-CHOP therapy shows great potential. [19] Due to missed diagnosis, the present case progressed, missing the optimal treatment opportunity, and survived for less than four months.

The diagnostic and treatment process of this case was not ideal. Firstly, the preliminary diagnosis did not match the expected final pathology, which resulted in a lack of confidence in the clinical diagnosis and treatment process. Our clinical diagnostic and treatment strategies were insufficient, and the patient’s demands and economic ability significantly impacted the diagnostic and treatment processes. We need to learn from this experience and improve future diagnoses and treatments; Secondly, there were some mistakes in the diagnosis and treatment processes. HIV combined with BL in the seminal vesicle is rare condition, and there is a close relationship between seminal vesicle tumors and prostate tumors, which can be easily misdiagnosed. We hope this case can increase clinical physicians’ awareness and provide inspiration for diagnosing rare location tumors in the HIV population. Reported diagnostic and treatment strategies could benefit patients with similar conditions. This report will hopefully serve as cautionary advice to doctors, especially urologists, to change their approach and broaden the thinking model in the clinical diagnosis and treatment process.