Imaging diagnosis
Case 139
【Progress】He underwent surgical cholecystectomy ten days later. Pathological examination revealed xanthogranulomatous cholecystitis.
【Discussion】
Xanthogranuloma is found in the whole body such as juvenile xanthogranuloma in the skin, xanthogranulomatous hypophysitis, xanthogranulomatous pyelonephritis and xanthogranulomatous cholecystitis (XGC). It is believed that xanthogranuloma results from response disorder of macrophages in the inflammatory absorbing process, leading the aggressive granulomatous reaction (1). Pathological examination reveals granuloma with infiltration of inflammatory cells and lipid-laden foamy macrophages (1, 2). It is believed that the precursor, the preceding inflammation or injury exists before formation of xanthogranuloma (2). Namely, it is considered that xanthogranulomatous hypophysititis comes from Rathke’s cleft cyst, xanthogranulomatous pyelonephritis comes from staghorn calc or pyelonephritis and XGC comes from gall bladder adenomyomatosis.
Adenomyomatosis called Rokitansky-Aschoff sinuses is formed of intramural diverticulum lined by mucosal epithelium (3). XGC comes from intramural rupture of adenomyomatosis probably by intraluminal pressure from incarcerated gallstone or biliary tract stone. Inflammatory cells and histiocytes (tissue macrophages) infiltrate to the rupture sites from vessels and engulfed the intramural bile incompletely, inducing to form aggressive and extensive granulation tissue. In our case, he experienced subacute cholecystolithiasis and cholecystitis, preceding XGC.
It is often difficult to distinct XGC from gall bladder cancer. Further, XGC occurs associated with gall bladder cancer with high incidence of 8.5 to 30.5% (2, 4). The typical radiological characteristic of XGC is the scattered small low density which mimic the swollen Rokitansky-Aschoff sinuses in the thickened mural of the gall bladder (5-7). The other radiological findings are presence of intact mucosal layer of gall bladder wall and absence of intrahepatic bile duct dilatation and hilar and/or retroperitoneal swollen lymph-nodes (5-7). These findings are not remarkable in case of gall bladder cancer. Further, MRI with out of phase show lowering signal intensity corresponded to XGC compared to MRI with in phase. This is probably because XGC includes subtle lipid component whereas gall bladder cancer does not (8). Furthermore, MRI with diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC) map is reported for differentiation between XGC and gall bladder cancer (9). In our case, enhanced CT showed scattered small low density in the thickened gall bladder with intact mucosal layer. MRI with DWI and ADC map showed high signal intensity and lowering of ADC values which indicate the difficulty from malignancy, whereas MRI with out of phase showed lowering of signal intensity of the thickened gall bladder wall compared to MRI with in phase which indicates the inclusion of fatty tissue.
【Summary】
We present a seventy three-year-old male with xanthogranulomatous cholecystitis (XGC) which is often difficult to distinct from gall bladder cancer. CT and MRI showed the typical findings of XGC: scattered small low density in the homogeneous thickened wall of the gall bladder. MRI with out-of-phase showed lowering signal intensity corresponded to the XGC compared the signal intensity on MRI with in-phase. It is borne in mind that xanthogranuloma can occur in the whole body: juvenile xanthogranuloma in the skin, xanthogranulomatous hypophysitis, xanthogranulomatous pyelonephritis and XGC. The precursor exists such as: xanthogranulomatous hypophysititis comes from Rathke’s cleft cyst, xanthogranulomatous pyelonephritis comes from staghorn calc or pyelonephritis and XGC comes from gall bladder adenomyomatosis. Pathological examination of reveals granuloma with infiltration of inflammatory cells and lipid-laden foamy macrophages. XGC comes from intramural rupture of adenomyomatosis probably by intraluminal pressure from incarcerated gallstone or biliary tract stone. MRI with out-of-phase is useful to detect adrenal adenoma, focal fatty liver and XGC.
【References】
1.Singh VP, et al. Xanthogranulomatous cholecystitis: What every radiologist should know. World J Radiol. 2016 Feb 28; 8(2): 183–191.
2.Rammohan A, et al. Xanthogranulomatous cholecystitis masquerading as gallbladder cancer: can it be diagnosed preoperatively? Gastroenterol Res Pract. 2014;25: 36-45.
3.Golse, N, et al. Gallbladder adenomyomatosis: Diagnosis and management. Journal of Visceral Surgery. 2017; 154: 345-353
4.Krishnani N, et al. Fine needle aspiration cytology in xanthogranulomatous cholecystitis, gallbladder adenocarcinoma and coexistent lesions. Acta Cytol. 2000;44:508–514.
5.Zhao F, et al. CT and MR features of xanthogranulomatous cholecystitis: an analysis of consecutive 49 cases. Eur J Radiol. 2013;82:1391–1397.
6.Goshima S, et al. Xanthogranulomatous cholecystitis: diagnostic performance of CT to differentiate from gallbladder cancer. Eur J Radiol. 2010;74:e79–e83.
7.Shuto R, et al. CT and MR imaging findings of xanthogranulomatous cholecystitis: correlation with pathologic findings. Eur Radiol. 2004;14:440–446.
8.Kang TW, et al. Differentiating xanthogranulomatous cholecystitis from wall-thickening type of gallbladder cancer: added value of diffusion-weighted MRI. Clin Radiol. 2013;68:992–1001.
9.Hatakenaka M, et al. Xanthogranulomatous cholecystitis: importance of chemical-shift gradient-echo MR imaging. Eur Radiol. 2003;13:2233–2235.
2019.3.6