Granulomatous renal masses following intravesical bacillus Calmette–Guérin therapy: the central unaffected calyx sign

Abstract

A 67-year-old man with a history of melanoma, treated surgically 7 years before, was referred for vomiting and right flank pain after three intravesical instillations of bacillus Calmette-Guérin (BCG) for superficial bladder cancer. A CT scan showed a mass on the right kidney, with a normal calyx in its centre. Percutaneous biopsy, obtained because of melanoma history, showed granulomatous reaction caused by BCG infection. The renal mass disappeared after 9 months of anti-tuberculous treatment. The presence of an unaffected calyx in the centre of the renal mass is an interesting finding for both teaching purposes--it clearly illustrates the pathogeny of the disease, with the bacillus invading the renal parenchyma through the papilla--and diagnostic purposes--a malignant tumour is likely to displace or destroy neighbouring calyces rather than leaving them unaffected. However, the diagnostic value of this sign remains to be determined by further research.

BCG-Related Renal Granulomas Managed Conservatively

“…[3][4][5][6][7][8][9][10][11][12]16,20 Perhaps the absence of fever in the two cases presented here could be related to the dose and strain of BCG used. Whereas in these two cases, 50 mg of BCG Tice strain was used, previous reports of febrile renal granulomas were reported with BCG Connaught strain 5,11,16 or BCG Tice strain at higher dose of 120 mg per installation. 9 A recent randomized clinical trial has shown that superior immunogenicity and efficacy of BCG Connaught strain when compared with BCG Tice strain.…”

“…In fact, several cases of nephroureterectomy have been reported since these masses were mistaken for renal cell carcinoma or urothelial carcinoma. 10,12,16 When analyzing available published case reports on renal granulomas, we found that most cases reported multifocality of renal granulomas with multiple renal masses on imaging studies, 4,8,[11][12]16 while others reported solitary renal foci. 5,7,9,10 Both patients in the present series had multiple renal granulomas.…”

“…Except for the case report by Mody and colleagues, in which the patient underwent nephroureterectomy, all of previous case reports of renal granulomas were treated with 6 to 12 months of anti-tuberculous medications. [3][4][5][6][7][8][9][10][11][12]16,20 Therefore, here we present two cases of asymptomatic renal granulomas that were managed without anti-tuberculous medications. However, the reason we were able to manage these patients without anti-tuberculous medications was related to the absence of fever and systemic symptoms.…”

“…Another sign is the "central unaffected calyx sign" on delayed phase CT images that has been previously described in patient with a renal BCG granuloma. 11 In contrast to a malignant tumour that would destroy neighbouring calyces, the authors discovered that renal BCG granuloma did not affect the calyx within the mass. 11 Although, not specific, this sign was present on the delayed phase CT images for the first patient (Fig.…”

“…3 A small number of granulomatous renal masses following intravesical BCG have been previously reported. [3][4][5][6][7][8][9][10][11][12] The incidence of such renal granulomas has been reported at a rate of 0.1% (2 cases out of 2602). 3 However, previous cases were managed with nephroureterectomy, anti-tuberculous medications or both.…”