Multilocular Mesothelial Cyst of the Spleen Mimicking Hydatid Cyst on Imaging

Mesothelial cyst of the spleen mimicking a metastasis: a case report

“…8 Primary epithelial cysts, which account for 10% of all splenic cysts, are further divided into dermoid, epidermoid or mesothelial, depending on the type of the lining cells on histopathological examination. 5 Mesothelial cysts may develop congenitally due to incomplete fusion and invagination of mesothelial-lined peritoneal surfaces, with subsequent secretion of fluid. 9 This theory explains the usual location of mesothelial cysts in the small bowel, mesentery, mesocolon and omentum.…”

“…4 However, in this current case, the mesothelial cyst was observed in a 66-year-old woman and it was suspected that the increase in the size of the splenic lesion was due to fluid accumulation within a late activated mesothelial cyst. Most primary splenic epithelial cysts are clinically silent and are often found incidentally or due to an abdominal mass or abdominal pain on imaging techniques, such as ultrasound (USG) or CT. 1,5,10 They are typically well-defined hypoechoic and hypodense lesion, with a thin or imperceptible wall, on USG and CT, respectively. 1,5,6,10 On magnetic resonance imaging, the cysts are hypointense on T1-weighted images and hyperintense on T2-weighted images, without reinforcement after contrast injection.…”

“…Most primary splenic epithelial cysts are clinically silent and are often found incidentally or due to an abdominal mass or abdominal pain on imaging techniques, such as ultrasound (USG) or CT. 1,5,10 They are typically well-defined hypoechoic and hypodense lesion, with a thin or imperceptible wall, on USG and CT, respectively. 1,5,6,10 On magnetic resonance imaging, the cysts are hypointense on T1-weighted images and hyperintense on T2-weighted images, without reinforcement after contrast injection. [11][12][13] However, the signal intensity may vary depending on the contents of the cyst.…”

“…1,6,8,10 However, there are a few reports on multilocular mesothelial cysts, some of which were misdiagnosed as hydatid cysts due to their shape. 5,15,16 The imaging findings and clinical characteristics of previously reported cases of splenic mesothelial cysts are detailed in Table 1. 1,5,6,[10][11][12][13]17 Hypodense lesions of the spleen are commonly found on CT images of the abdomen.…”

“…[2][3][4] The radiological features of splenic mesothelial cysts have been described as cystic lesions that are unilocular, smooth and with well-defined margins. 5,6 However, due to the rarity of these cysts, it remains unclear whether these characteristics are representative and specific enough for diagnosis.…”