Key Points
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The detection of incidental cystic lesions may cause diagnostic confusion in patients having a history of cancer.
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Some syndromes predisposing the affected individual to different tumors may cause cystic lesions in the abdominal organs and rarely, the tumors can be cystic.
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Correct diagnosis of the benign cystic lesions is critical as they may simulate several other benign and malignant acquired diseases of the abdomen, all of which have very different treatment approaches and prognostic implications.
Introduction
Organ | Disease | Typical imaging findings | |
---|---|---|---|
Liver and biliary tract | Polycystic liver disease | - Cysts located within the peripheral parenchyma - Peribiliary cysts - Fluid level, cyst wall thickening, calcification and endocavitary air bubbles, if infection is present - Hyperdensity on CT and hyperintensity on T1W MR images could be seen due to the hemorrhage or infection | |
Caroli disease | - Cystic appearing enlarged intrahepatic bile ducts - Central dot sign (portal radicle within the dilated bile duct) - Endoluminal stones or sludge may be observed | ||
Choledochal cysts | Type-I | - Type IA: Diffuse cystic dilation of the extrahepatic bile duct - Type IB: Focal cystic dilation of the extrahepatic bile duct - Type IC: Diffuse fusiform dilation of the entire extrahepatic bile duct | |
Type-II | - Focal diverticular outpouching of the common bile duct | ||
Type-III | - Intramural dilation of the most distal portion of the common bile duct (choledochocele) | ||
Type-IV | - Type IVA: Combined saccular shaped dilations in the intrahepatic and extrahepatic bile ducts - Type IVB: Saccular dilations restricted to extrahepatic bile ducts | ||
Type-V | - Caroli disease | ||
Biliary hamartomas(von Meyenburg complex) | - Innumerable subcentimeter cysts spread throughout the liver parenchyma | ||
Ciliated hepatic foregut cyst | - Unilocular cystic lesion located in the subcapsular area along the anterior surface of the liver with segment 4 being the most common location | ||
Kidney | Autosomal dominant polycystic kidney disease | - Early stage: Single or multiple cysts in one or both kidneys - Final stage: Multiple cysts completely replacing the entire renal parenchyma - Hyperdensity on CT (a) and hyperintensity on T1W(b) MR(c) images in case of hemorrhage | |
Autosomal recessive polycystic kidney disease | - Enlarged kidneys with thickened hyperechoic parenchyma caused by microcysts - Larger cysts (>1 cm) may accompany in some cases - Suggestive findings of hepatic abnormalities including congenital hepatic fibrosis, Caroli disease, and bile duct ectasia | ||
Multicystic dysplastic kidney disease | - Unilateral cysts in disorganized pattern completely replacing the renal parenchyma, which may be observed on antenatal US(d) | ||
Nephronophthisis and medullary cystic kidney disease | - Early stage: Hyperechoic renal parenchyma with the loss of corticomedullary differentiation - Advanced stage: Cysts, of varying size, in medullary and corticomedullary locations. The kidneys appear small due to parenchymal fibrosis | ||
Von Hippel-Lindau disease | - Bilateral renal cysts of varying histopathologic features, ranging from simple and hyperplastic cysts to cystic clear cell carcinomas | ||
Tuberous sclerosis complex | - Bilateral simple renal cysts with accompanying angiomyolipomas | ||
Pancreas | Von Hippel-Lindau disease | - Simple cysts - Serous cystadenomas - Cystic or solid neuroendocrine tumors | |
Multiple endocrine neoplasia type I | - Cystic or solid neuroendocrine tumors | ||
Cystic fibrosis | - Complete or partial fatty replacement of the pancreas - Atrophy of the pancreas - Simple cysts completely replacing the parenchyma (pancreatic cystosis) | ||
Gastrointestinal tract | Duplication cysts | - Cyst within the close proximity of the bowel segment - The double wall sign (inner hyperechoic mucosa and outer hypoechoic muscularis propria) - “Y configuration” that is indicative of a shared wall with the cyst and the neighboring bowel wall - Internal septation or luminal debris may be observed due to the infection | |
Lymphatic system | Lymphatic malformations | - Well-circumscribed cystic lesion with internal septations - The fluid content of the lesion may contain fat - Small lesions may change location on follow-up imaging | |
Diaphragm *[29] | Mesothelial cyst | - Homogeneous bilobulated cystic lesion located between posterolateral aspect of the right liver lobe and the adjacent diaphragm | |
Prostate | Prostatic utricle cyst | - Midline cyst communicating with the prostatic urethra and not extending above the base of the prostate | |
Mullerian duct cyst | - Teardrop-shaped midline cyst extending above the superior margin of the prostate and not communicating with the prostatic urethra | ||
Urachus *[32] | Urachal cyst | - Homogeneous midline cyst along the trajectory of the urachus (between the bladder dome and umbilicus) - Inhomogeneous cyst content, cyst wall thickening, and inflammatory stranding adjacent to the cyst indicate infection | |
Zinner’s syndrome *[33] | Seminal vesicle cysts | - Ipsilateral renal agenesis, seminal vesicle cysts, and ejaculatory duct obstruction - In case of hemorrhage or infection the cyst content may appear as bright on T1W MR images |