Intravesical Bacillus Calmette-Guérin (BCG) instillation is an established immunotherapy for superficial bladder cancer. Herein, we describe a case of disseminated BCG infection that developed immediately after the first BCG injection. A 76-year-old man diagnosed with non-invasive bladder cancer underwent intravesical BCG instillation; he developed high fever and systemic arthralgia later that night. General examination did not reveal any infectious sources, and a combination therapy of isoniazid, rifabutin, and ethambutol was initiated after collecting his blood, urine, bone marrow, and liver biopsy samples for mycobacterial cultures. Three weeks later, Mycobacterium bovis was detected in the urine and bone marrow samples, and pathological investigation of liver biopsy revealed multiple small epithelial granulomas with focal multinucleated giant cells, leading to a diagnosis of disseminated BCG infection. The patient recovered after long-term antimycobacterial therapy without remarkable sequelae. Most cases of disseminated BCG infection occur after several doses of BCG injections, and its onset reportedly varies among cases, ranging from a few days to several months. The present case was notable as disease onset was observed only a few hours after the first BCG injection. Although rare, development of disseminated BCG infection should be considered as a differential diagnosis in patients at any time after intravesical BCG instillation therapy.

The differential diagnosis of retroperitoneal masses includes a variety of benign and malignant conditions, among which infections constitute a significant subgroup. Familiarity with these infectious pseudotumours could facilitate prompt diagnosis. In this report, we describe three patients with an infectious pseudotumour, which was clinically and radiologically highly suggestive of a neoplasm. The first patient was a 62-year-old woman with a history of Richter syndrome, who seven months after allogeneic haematopoetic stem cell transplantation from an unrelated donor presented with a renal mass. A renal biopsy at that time revealed necrotic tissue. The patient displayed multiple relapses of Richter syndrome (for which she received also chimeric antigen receptor T-cell therapy salvage chemotherapy) and remissions of the lymphoma as well as an Aspergillus pneumonia for which she was treated with intravenous ambisome and afterwards oral posaconazole. Since the renal mass persisted and to exclude malignancy, nephrectomy was performed which revealed the presence of fungal hyphae. The second patient was a 51-year-old man with a history of a low-grade non-muscle-invasive bladder urothelial carcinoma, who after Mycobacterium bovis Calmette-Guerin instillation presentedwith fever and a suspicious renal mass. A partial nephrectomy was performed. Intraoperative frozen section analysis and routine histology suggested a Mycobacterium bovis-associated lesion, which was confirmed by polymerase chain reaction (PCR) analysis. The third patient was an 85-year-old man who presented with loss of appetite, fatigue, and significant weight loss (24 Kg in less than a year) as well as a travel history. The laboratory tests showed a low sodium and a high potassium level. CT scans revealed a solitary lesion in the right lung, a small liver lesion as well as bilateral adrenal lesions. A CT-guided biopsy revealed the presence of Histoplasma capsulatum, which was confirmed by PCR analysis. A retrospective review of all parameters indicates that all three patients presented with some risk factors, such as immunosuppression, travel, or clinical history that could raise the suspicion of infection in order to be included in the differential diagnosis, thus providing an additional tool for timely diagnosis.

Multisystem Inflammatory Syndrome in Children (MIS-C) is a rare febrile disorder with multisystem organ involvement temporally associated with coronavirus 2019 infection (COVID-19) and frequently exhibits features mimicking Kawasaki disease (KD), another febrile disorder in children. The pathogenesis and the full clinical spectrum of MIS-C is poorly understood: It is still unclear whether MIS-C and KD are different syndromes or represent a common spectrum. The erythema and induration of Bacillus Calmette-Guérin (BCG) scar is one of the characteristic findings of KD, and is useful for the diagnosis in countries where BCG vaccination is mandated in infancy. Furthermore, such findings in BCG scar were also reported after SARS-CoV-2 vaccination, which may be related to molecular mimicry. However, there are no reports of changes at the BCG scar in MIS-C cases. Here, we report a case of MIS-C in a 3-year-old Hispanic boy in Japan, with erythema and induration at the BCG scar. The patient received BCG vaccination at 16 months of age in Japan. Four weeks before the onset, he had positive polymerase chain reaction (PCR) results for SARS-CoV-2 following household outbreak, although he was asymptomatic. He presented with fever and gastrointestinal symptoms, followed by the appearance of all six principal findings of complete KD. He exhibited congestive heart failure, following intravenous immunoglobulin (IVIG) therapy. He was diagnosed with MIS-C based on characteristic mucocutaneous and gastrointestinal symptoms, decreased cardiac function, and coagulopathy, in addition to laboratory data consistent with MIS-C. The BCG finding was present from the early stage of the disease. The patient was refractory to two doses of IVIGs, and the third IVIG plus prednisolone resulted in defervescence and improvement in heart failure. No coronary involvement was observed. This is the first case of erythema and induration at the BCG scar associated with MIS-C accompanied by KD features, which may give clinical and mechanistic insights in the understanding of the disease. Since the full spectrum of MIS-C is still evolving and both of them are syndromes with overlapped clinical features, further studies are warranted for deep phenotyping of MIS-C with KD features relative to KD in countries with mandatory BCG programs in infancy.

Mendelian susceptibility to mycobacterial diseases (MSMD) is a rare condition of primary immunodeficiency disorder. Interleukin-12 receptor β1 (IL12RB1) deficiency, is the most common genetic etiology of MSMD, which is characterized by the selective predisposition to clinical disease caused by weakly-virulent mycobacteria, such as Bacillus Calmette-Guérin (BCG) vaccines, and environmental non-tuberculous mycobacteria (NTM). To the best of our knowledge, this is the first case of IL12RB1 deficiency to be reported from Iraq. Our case is an 8-year-old Syrian girl, for first-cousin parents, with a refugee-status in the North of Iraq. She had a history of disseminated BCG infection 2 months after receiving BCG vaccine, in addition to repeated episodes of mild or severe illnesses, such as maculopapular skin rash, lymphadenopathy, gastroenteritis, meningitis, and clinically diagnosed tuberculosis (TB) based on local TB-prevalence setting. Because of limited medical facilities in the war-torn countries; in Syria and Iraq, no diagnosis could be reached. We used Flinders Technology Associates (FTA) cards to transfer her bone marrow aspirate to Japan. A homozygous IL12RB1 mutation was detected by whole exome sequencing in Japan, using genomic-DNA extracted from dried bone marrow sample spots on FTA filter paper. In conclusion, diagnosis of MSMD due to IL12RB1 deficiency was possible by transferring the FTA sample of the patient for genetic evaluation in Japan. Our report recalls the need of pediatricians in countries with TB-prevalence and high parental consanguinity, to consider IL12RB1 deficiency in the differential diagnosis of a child with clinical evidence of TB, especially with the history of disseminated BCG disease.