Tuberculous Prostatic Abscess Following Intravesical Bacillus Calmette-Guérin Immunotherapy

Intravesical Bacillus Calmette-Guérin (BCG) immunotherapy is a widely accepted treatment for high-risk non-muscle invasive bladder cancer (NMIBC). While generally safe, this therapy can lead to rare complications, including tuberculous infections in the prostate. This case report describes a 57-year-old man who developed a tuberculous prostatic abscess following intravesical BCG immunotherapy, highlighting the importance of early diagnosis and appropriate management.

Case Presentation

The patient, a 57-year-old man with no history of tuberculosis, was diagnosed with high-grade T1 urothelial carcinoma of the bladder. He underwent transurethral resection of the bladder tumor and subsequently received intravesical BCG immunotherapy. The treatment regimen consisted of weekly instillations of 120 mg BCG in 50 mL saline for six weeks. The BCG used was BCG for Therapeutic Use, manufactured by CDIBP, China.

After completing the six-week course of BCG immunotherapy, the patient began experiencing perineal discomfort. A digital rectal examination (DRE) revealed tenderness in the left lobe of the prostate, raising suspicion of a prostatic infection. Microscopic urinalysis showed a few red blood cells, but no other significant abnormalities were noted. The total prostate-specific antigen (PSA) level was measured at 2.61 ng/mL, with a free PSA level of 0.23 ng/mL.

To further evaluate the suspected prostatic infection, a magnetic resonance (MR) scan was performed. The MR imaging revealed a hypo-intense lesion measuring approximately 2.1 cm by 1.2 cm on T2-weighted imaging (T2WI) in the peripheral zone of the left prostate gland. The lesion also exhibited hyper-intensity on diffusion-weighted imaging. These findings suggested the presence of a prostatic abscess.

To confirm the diagnosis and rule out other potential causes, a prostate biopsy was performed. Histological examination of the biopsy specimen revealed granulomatous prostatitis. Polymerase chain reaction (PCR) testing confirmed the presence of Mycobacterium tuberculosis in the prostate tissue. There was no evidence of tuberculosis in other parts of the body, indicating that the infection was localized to the prostate.

Based on these findings, the patient was diagnosed with a tuberculous prostatic abscess. He was started on a 9-month anti-tuberculous treatment regimen, which included isoniazid (300 mg/day), rifampicin (450 mg/day), and ethambutol (750 mg/day). The patient’s symptoms improved significantly after one month of therapy. A follow-up MR scan performed after the completion of the 9-month treatment regimen showed complete resolution of the prostatic abscess. Additionally, a recent cystoscopy revealed no evidence of tumor recurrence or inflammation in the prostate.

Discussion

Intravesical BCG immunotherapy is considered the first-line adjuvant treatment for patients with high-risk NMIBC following surgical resection. The therapy works by inducing a local immune response that targets residual cancer cells in the bladder. While generally well-tolerated, BCG immunotherapy can lead to complications, including localized infections such as granulomatous prostatitis and, in rare cases, tuberculous prostatic abscess.

The development of tuberculous prostatic abscess following intravesical BCG immunotherapy is an extremely rare complication. The infection can occur through hematogenous spreading or direct extension from the bladder. In this case, the patient developed a tuberculous prostatic abscess after completing the standard 6-week course of BCG immunotherapy. The diagnosis was confirmed through a combination of clinical examination, imaging studies, and histological analysis.

The management of tuberculous prostatic abscess typically involves a combination of anti-tuberculous medications and, in some cases, surgical drainage. In this patient, conservative treatment with a 9-month course of anti-tuberculous drugs was sufficient to resolve the abscess, and surgical intervention was not required. This outcome suggests that conservative treatment with anti-tuberculous drugs may be effective in managing tuberculous prostatic abscess, and surgical drainage may not always be necessary.

The diagnosis of a prostate abscess can be challenging, as the symptoms and imaging findings may overlap with other conditions, such as prostate cancer. In this case, the initial suspicion of infection was raised based on the patient’s symptoms and DRE findings. The MR scan provided further evidence of a prostatic lesion, and the biopsy confirmed the presence of granulomatous prostatitis with tuberculosis. This highlights the importance of a thorough diagnostic workup, including imaging and histological analysis, in patients with suspected prostatic abscess.

The rate of granulomatous prostatitis following intravesical BCG immunotherapy is approximately 0.9%, but the development of a tuberculous prostatic abscess is even rarer. The exact mechanism by which BCG immunotherapy leads to tuberculous infection in the prostate is not fully understood, but it is thought to involve a combination of direct extension from the bladder and hematogenous spreading. The risk of developing a tuberculous prostatic abscess may be influenced by factors such as the patient’s immune status and the dose and duration of BCG therapy.

If left untreated, a tuberculous prostatic abscess can progress to sepsis, highlighting the importance of early diagnosis and treatment. The treatment of tuberculous prostatic abscess typically involves a prolonged course of anti-tuberculous medications, with or without surgical drainage. In this case, the patient responded well to anti-tuberculous therapy alone, and surgical drainage was not required. This suggests that conservative treatment with anti-tuberculous drugs may be sufficient in some cases, particularly if the abscess is diagnosed and treated early.

Conclusion

This case report illustrates the potential for tuberculous prostatic abscess to develop as a rare complication of intravesical BCG immunotherapy for bladder cancer. The diagnosis of a tuberculous prostatic abscess requires a thorough diagnostic workup, including clinical examination, imaging studies, and histological analysis. Conservative treatment with anti-tuberculous drugs may be effective in managing this condition, and surgical drainage may not always be necessary. Clinicians should be aware of this rare complication and consider it in the differential diagnosis of patients with prostatic symptoms following intravesical BCG immunotherapy.

doi.org/10.1097/CM9.0000000000000414

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