Incidental Detection of Granulomatous Prostatitis by F-18 FDG PET/CT in a Patient with Bladder Cancer: A Rare Complication of BCG Instillation Therapy

Biopsy-diagnosed renal granuloma after intravesical bacillus Calmette-Guérin therapy for bladder carcinoma: a case series and review of the literature

Renal granuloma is a rare complication affecting the kidneys after intravesical bacillus Calmette-Guérin (BCG) therapy for bladder carcinoma. Our case series review describes the imaging and histopathological findings of BCG-induced renal granulomas. All three renal granulomas, which were located in the upper pole, had a solitary mass-like appearance. The mean diameter was 31.3 mm. In the two cases, the lesion was homogeneously enhanced on post-contrast CT, and presented homogeneous low signal intensity on T₂ weighted imaging (T₂WI) and iso-signal intensity on diffusion-weighted imaging (DWI). Both lesions had increased fludeoxyglucose (FDG) uptake. Histological examinations revealed granulomatous inflammation with fibrosis. The third case showed a lesion having heterogeneous enhancement on CT, heterogeneous and slightly high signal intensity on T₂WI, and high signal intensity on DWI. This case showed more severe inflammatory cell infiltration and less fibrosis than the former two cases did. It was suggested that the signal intensity on T₂WI and DWI depends on the degree of inflammation and fibrosis in renal granuloma. It is currently challenging to distinguish renal granuloma from renal malignancy based on only imaging findings. Biopsies were helpful in confirming the diagnosis and avoiding unnecessary resection. Renal granuloma should be considered as a differential diagnosis when a renal mass is found in a patient with a history of intravesical BCG treatment.

Granulomatous Prostatitis After Intravesical Bacillus Calmette-Guérin Instillation Therapy: A Potential Cause of Incidental F-18 FDG Uptake in the Prostate Gland on F-18 FDG PET/CT in Patients with Bladder Cancer

PURPOSE

This study aimed to evaluate the possibility that Bacillus Calmette-Guérin (BCG)-induced granulomatous prostatitis can be a potential cause of benign F-18 FDG uptake.

METHODS

A total of 395 bladder cancer patients who underwent F-18 FDG PET/CT (PET/CT) were retrospectively evaluated. Patients were divided into two groups according to BCG therapy status. Elapsed time after BCG therapy, serum PSA level, results of prostate biopsy, and the SUVmax and uptake pattern in the prostate gland were reviewed. For patients who underwent follow-up PET/CT, the changes in SUVmax were calculated.

RESULTS

While 35 % of patients showed prostate uptake in the BCG therapy group, only 1 % showed prostate uptake in the non-BCG therapy group (p < 0.001). Among 49 patients with FDG-avid prostate lesions, none had suspected malignancy during the follow-up period (median: 16 months). Five patients revealed granulomatous prostatitis on biopsy. The incidence of FDG-avid prostate lesions was significantly higher if the elapsed time after BCG therapy was less than 1 year compared to more than 1 year (p < 0.001). Serum PSA was normal in 88 % of patients. All patients with incidental F-18 FDG uptake in the prostate gland showed focal or multifocal prostate uptake, and median SUVmax was 4.7. In 16 patients who underwent follow-up PET/CT, SUVmax was decreased in 14 patients (88 %) without treatment, and no patients demonstrated further increased prostate uptake (p < 0.001).

CONCLUSIONS

BCG-induced granulomatous prostatitis can be a potential cause of benign F-18 FDG uptake, especially in those with a history of bladder cancer treated with BCG. In BCG-induced granulomatous prostatitis, focal or multifocal prostate uptake is frequently seen within 1 year after BCG therapy, and the intensity of prostate uptake is decreased on the follow-up PET/CT without any treatment.

Complications of intravesical bacillus calmette-guérin

Intravesical Bacillus Calmette-Guérin (BCG) is an important treatment for the management of non-muscle invasive bladder cancer because of its proven efficacy and favourable safety profile. The most common complications associated with BCG treatment are relatively minor. They include urinary frequency, cystitis, fever, and hematuria. Although serious complications are rare, patients can develop severe, life-threatening sepsis with disseminated mycobacterial infection. We report a rare case of periurethral diverticulum formation after intravesical BCG and review the literature on the potential complications of this treatment modality.

Incidental uptake of 18F-fluorodeoxyglucose in the prostate gland. Systematic review and meta-analysis on prevalence and risk of malignancy

AIM

To perform a systematic review and meta-analysis of published data on the prevalence and risk of malignancy of prostatic incidental uptake (PIU) detected by fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) or PET/computed tomography (PET/CT).

PATIENTS, MATERIAL, METHODS

A comprehensive literature search of studies published up to February 2014 was performed. Pooled prevalence and malignancy risk of PIU were calculated on a per patient-based analysis including 95% confidence interval (95%CI). Furthermore, we assessed some parameters as potential predictors of malignant PIU.

RESULTS

Six studies including 47925 patients who underwent 18F-FDG PET/CT were selected. Pooled prevalence of PIU was 1.8% (95%CI: 1.3-2.3%). Overall, 444 patients with PIU were further evaluated and 121 underwent biopsy. The pooled risk of malignancy in patients with PIU further evaluated or verified by biopsy were 17% (95%CI: 12-23%) and 62% (95%CI: 54-71%), respectively. A higher mean age was observed in the group of malignant PIUs compared to benign PIUs. There was a trend towards a higher mean SUV(max) in the group of malignant PIUs but without a statistically significant difference compared to benign PIUs. Peripheric site of PIU but not presence or absence of calcification was a predictor of malignancy.

CONCLUSIONS

PIU is observed in about 1.8% of 18F-FDG PET/CT scans performed in male patients carrying a significant risk of malignancy. Therefore, whenever a PIU is detected further investigation is warranted to exclude malignancy, in particular when PIU is located in the peripheric site of prostate gland.

A late presentation of isolated lymph node tuberculosis postintravesical BCG therapy for superficial bladder cancer: a novel case

Intravesical BCG immunotherapy is commonly used in the treatment of superficial bladder cancer. We recount the case of an 82-year-old British man who completed a course of BCG immunotherapy in 2011 for superficial bladder cancer, and presented in January 2013 with a loss of appetite, loss of weight and severe back pain. CT scanning, followed by MRI displayed a 5.7 cm × 5 cm conglomerated necrotic, haemorrhagic mass of lymph nodes in the para-aortic region. A CT-guided biopsy revealed granulomatous inflammation, focal fibrosis and acid-fast bacilli consistent with Mycobacterium tuberculosis (TB). The patient was treated with combination antituberculous medication, and is recovering. To our knowledge, this is the only reported case of lymph node TB secondary to intravesical BCG immunotherapy. We suggest that in patients treated with postintravesical BCG with enlarged lymph nodes, a diagnosis of secondary TB should be considered.

FDG PET imaging in a patient with primary seminoma of the prostate

Primary seminoma of the prostate is extremely rare. We describe a case of a 35-year-old man who presented with difficulty in urinating. Physical findings were unremarkable, but a rectal examination revealed a slightly hardened prostate with a nodule in the right lobe. Blood parameters were normal; however, blood chemistry revealed slightly elevated lactic dehydrogenase, and microscopic hematuria was evident. Serum prostate acid phosphate, carcinoembryonic antigen, and alpha-fetoprotein values were within normal limits. Both computed tomography and magnetic resonance images revealed a large mass in the prostate gland. A prostatic sarcoma or malignant lymphoma was initially suspected. A systemic survey using 18-fluoro-2-deoxyglucose (F-18 FDG) positron emission tomography revealed focal FDG uptake in the prostate gland. A prostatic biopsy of the mass was histologically diagnosed to reveal an extragonadal seminoma.

Incidental Focal (18)F-FDG Uptake in the Prostate: Clinical Significance and Differential Diagnostic Criteria

PURPOSE

The extent and intensity of (18)F-FDG uptake in prostate cancer patients are known to be variable, and the clinical significance of focal (18)F-fluorodeoxyglucose ((18)F-FDG) uptake that is incidentally found on positron emission tomography (PET) has not been established. We investigated the clinical significance of incidental focal prostate uptake of (18)F-FDG on PET/computed tomography (CT) and analyzed differential findings on PET/CT between malignant and benign uptake.

METHODS

A total of 14,854 whole-body (18)F-FDG PET/CT scans (4,806 that were conducted during cancer screening and 10,048 that were conducted to evaluate suspected or alleged cancer outside of the prostate) were retrospectively reviewed to determine the presence, location, multiplicity and maximum standardized uptake value (SUVmax) of focal prostate uptake and combined calcification. The final diagnosis determined by serum prostate-specific antigen (PSA) level and biopsy was compared with PET findings.

RESULTS

Incidental focal prostate uptake was observed in 148 of 14,854 scans (1.0 %). Sixty-seven of these 148 subjects who had diagnostic confirmation were selected for further analysis. Prostate cancer was diagnosed in nine of 67 subjects (13.4%). The remaining 58 subjects had no malignancy in the prostate based on normal serum PSA level (n = 53), or elevated serum PSA level with a negative biopsy result (n = 5). While 84.6% (11/13) of malignant uptake was peripherally located in the prostate glands, 60.2% (50/83) of benign uptake was centrally located (p < 0.05). The positive predictive value of peripheral focal uptake for malignancy was 25%. The SUVmax, multiplicity and combined calcification were not significantly different between the two groups.

CONCLUSION

Although incidental focal (18)F-FDG uptake in the prostate is not common, the incidence of cancer with focal uptake is not low. Therefore, these findings deserve further evaluation. The location of the focal prostate uptake may help with the selection of high-risk prostate cancer patients.

Mycobacterial infection after intravesical bacillus Calmette-Guërin treatment for bladder cancer: a case report

Bacillus Calmette-Guërin (BCG) has been traditionally used as a vaccine against tuberculosis. Further, intravesical administration of BCG has been shown to be effective in treating bladder cancer. Although BCG contains a live attenuated strain of Mycobacterium bovis, complications such as M. bovis BCG infection caused by BCG administration are extremely rare. Here, we report a case of BCG infection occurring after intravesical BCG therapy. A 67-yr-old man presented with azotemia and weight loss. He had been diagnosed with bladder cancer 4 yr back, and had undergone transurethral resection of the bladder tumor and intravesical BCG (Tice strain) therapy at that time. An acid-fast bacterial strain was isolated from his urine sample. We did not detect Mycobacterium tuberculosis protein 64 (MPT-64) antigen in the isolates obtained from his sample, and multiplex PCR and PCR-reverse blot hybridization assay indicated that the isolate was a member of the M. tuberculosis complex, but was not M. tuberculosis. Finally, sequence analysis of 16S ribosomal RNA and DNA gyrase, subunit B (gyrB) suggested that the organism was M. bovis or M. bovis BCG. Although we could not confirm that M. bovis BCG was the causative agent, the results of the 3 molecular methods and the MPT-64 antigen assay suggest this finding. This is an important finding, especially because M. bovis BCG cannot be identified using common commercial molecular genetics tools.

Incidental fleurodeoxyglucose uptake in the prostate

This commentary confirms the rarity of prostatic cancer associated with incidental prostatic fleurodeoxyglucose (FDG) uptake. The study adds to the literature by showing that even if a prostate lesion is FDG avid it is unlikely to be due to cancer. The commentary considers the management of incidental prostate FDG uptake on the basis of the available evidence.

Unexpected primary osseous lymphoma as the cause of lactic acidosis in a patient suffering from pancreatitis

A 45-year-old man was admitted due to acute pancreatitis. A severe lactic acidosis was found. Following active therapy, the signs and symptoms from pancreatitis was improved, but acidosis was exacerbated. FDG PET/CT images were acquired to investigate the etiology of lactic acidosis and/or other unknown pathology. The images showed widespread abnormal FDG activity in the bone marrows throughout the body, suggestive of hematologic malignancy, which was confirmed as primary osseous non-Hodgkin lymphoma following a histopathological examination of the bone marrow. Chemotherapy against lymphoma was initiated and status of the lactic acidosis was rapidly corrected.

Intussusception incidentally detected by FDG-PET/CT in a pediatric lymphoma patient

An FDG-PET/CT scan was performed in a 14-year-old boy for the purpose of staging known lymphoma. The PET images identified the primary bowel lymphoma while the corresponding CT portion of the study found the intussusception caused by the lymphoma. The incidental finding of intussusception changed the management regime of the patient. Careful evaluation of both PET and CT images of the PET/CT is essential in providing the best patient care.