Yong YS, et al. J Korean Soc Radiol. 2025 Jan;86(1):45-67. https://doi.org/10.3348/jksr.2024.0055

Primary renal mucinous cystadenoma is a benign cystic renal lesion reported in fewer than 50 cases in English literature. We present a case of a complex cystic lesion of the left kidney in a 74-year-old gentleman with a significant background of left urolithiasis and hydronephrosis. This lesion showed gradual increase in size over eleven years and resulted in gross hydronephrosis and chronic renal impairment. Latest CT and MR imaging demonstrated a Bosniak 4 cystic mass with enhancing nodules suspicious for malignancy. A radical nephrectomy of the left kidney and histopathological examination demonstrated a benign mucinous cystadenoma.

Extrapulmonary tuberculosis represents 15–20% of all tuberculosis infections and can involve nearly any organ, earning tuberculosis a reputation as one of the great mimickers in medicine. Imaging plays a critical role in diagnosing extrapulmonary tuberculosis, which presents with a wide range of manifestations. We present a pictorial essay comprising cases from Asia, where tuberculosis remains endemic, illustrating the imaging characteristics of extrapulmonary tuberculosis with a focus on thoracoabdominal pathology. Differential diagnoses that exhibit similar imaging findings are also discussed. We aim to raise awareness among radiologists about the importance of considering extrapulmonary tuberculosis for accurate diagnosis and timely management.

Immunoglobulin G4-related disease (IgG4-RD) is a systemic fibroinflammatory disease characterized by raised serum IgG4 levels and tumefactive inflammation affecting multiple organ systems, typically involving the pancreas and biliary tree. Though rare, prostatic involvement has been reported in a few cases and is suspected to be an underreported entity. Our patient is a 63-year-old gentleman who has presented with an incidental “PI-RADS 5” (Prostate Imaging Reporting & Data System) prostate lesion and perivascular soft tissue cuffing of the superior rectal vessels on MRI rectum performed for surveillance of rectal neuroendocrine tumor. He had a history of lacrimal gland IgG4-RD. The lentiform prostate lesion subtly indents the prostate capsule, reminiscent of a periprostatic rather than an intraprostatic lesion. Perivascular cuffing of superior rectal vessels suggest inflammatory vasculitis of IgG4-RD. Differential diagnosis of periprostatic inflammatory IgG4-RD was considered, subsequently proven on MRI-ultrasound fusion targeted biopsy. Reported radiological findings of prostate IgG4-RD typically show diffuse chronic inflammation of the prostate, with a minority of the reports describing focal involvement, often mimicking focal prostate adenocarcinoma. Focal periprostatic involvement of IgG4-RD is an unusual manifestation which should be considered in patients with IgG4-RD who present with a periprostatic pseudotumor. IgG4-RD of the prostate usually responds well to steroid treatment without the need for surgery.

Background: Intraductal papillary mucinous neoplasm (IPMN) is a mucin-producing pancreatic tumor with variable malignant potential. While most are asymptomatic and indolent, a subset progress to invasive carcinoma or cause local complications such as pancreatitis. Spontaneous fistulation into adjacent organs is an increasingly recognized phenomenon with impact on prognosis and management. The incidence of fistulation in IPMN in the reported literature is 1.9–6.6%. The most common sites are the stomach, duodenum and bile duct. Reported outcomes are poor, with a median survival of approximately 16 months. Methods: We describe four patients with IPMN complicated by fistula, confirmed by endoscopic or histopathological evaluation with CT and MRI images and discuss the available literature of fistulating IPMN. Results: Fistulation occurred at the common bile duct, stomach, duodenum and duodeno-jejunal junction. Two of four patients passed away at 4.8 and 24.8 months from detection of fistula. Histology revealed high-grade dysplasia or invasive carcinoma in most patients, highlighting the aggressive nature of IPMNs complicated by fistulae. Conclusions: Our findings reinforce the importance of recognizing fistula formation as a marker of aggressive disease in IPMN. Although surgical resection remains the treatment of choice in suitable candidates, the rarity of this entity means that standardized management guidelines are lacking.