Keywords
follicular cholecystitis - magnetic resonance imaging - xanthogranulomatous cholecystitis
Introduction
Chronic follicular cholecystitis (CFC) is a rare entity that represents less than
2% of cholecystectomies. All reported cases have been managed surgically with the
diagnosis made postoperatively based on histological findings.[1] To the best of our knowledge, there are no magnetic resonance imaging (MRI) reports
about this pathology. We present a case of CFC and describe and illustrate the imaging
findings. For the first time, we report the presence of surrounding inflammatory changes.
Case Presentation
A 66-year-old man was referred to our hospital for having right-sided abdominal pain
and dyspepsia. The patient's symptoms had started 4 months ago. The patient's medical
history was unremarkable except for the presence of high blood pressure. The physical
abdominal examination was unremarkable. The laboratory findings showed elevated erythrocyte
sedimentation rates (45 mm), normal leukocytes count (8900/mL) with 65% of segmented
neutrophils, an elevated carbohydrate antigen 19–9 (CA 19–9) of 531.9 UI/L, and normal
carcinoembryonic antigen (CEA) of 1.8 UI/L.
Abdominal ultrasound (US) was performed, which showed a heterogeneous thickening of
the gallbladder fundus wall with low resistance flow on power Doppler and hypoechoic
intramural nodules ([Fig. 1]). The MRI revealed intramural nodules with elevated T2WI signal intensity ([Fig. 2]) and heterogeneous signal intensity and contrast-enhancement of the thicken fundus
wall ([Fig. 3]). Diffusion-weighted imaging (DWI) showed an increase in signal intensity on successively
higher-b-value DWI images and low signal intensity on the corresponding apparent diffusion
coefficient (ADC) map, with a value of 0. 9 × 10−3 mm2/s ([Fig. 4]). The surrounding gallbladder and liver parenchyma had inflammatory changes.
Fig. 1 (A-D) Ultrasound. A heterogeneous thickened gallbladder wall is shown with low resistance
flow on power Doppler and hypoechoic intramural nodules (arrows).
Fig. 2 (A and B) MRI. Axial (A) and coronal (B) T2WI show a heterogeneous thickened gallbladder fundus wall with high-intensity
nodules, similar to XGC. XGC, xanthogranulomatous cholecystitis.
Fig. 3 (A–H) MRI. Contrast-enhanced arterial (A–D) and portal phases (E–H) show a heterogeneous contrast-enhancement of the thickened fundus wall. The intramural
nodules remain hypointense (arrows). The surrounding liver parenchyma (asterisk) and
mesenteric fat adjacent to the gallbladder (dotted arrow) show inflammatory changes.
MRI, magnetic resonance imaging
Fig. 4 (A and B) MRI. DWI (A) and ADC (B) show restriction in the thickened wall (arrow). ADC, apparent diffusion coefficient;
DWI, diffusion-weighted imaging; MRI, magnetic resonance imaging.
A presumptive diagnosis of xanthogranulomatous cholecystitis (XGC) versus gallbladder
carcinoma was made and surgery was performed. No preoperative fine-needle aspiration
or biopsy was made because suspicion of gallbladder cancer was high due to the size
of the lesion and the high values of CA 19–9. The gallbladder was found adhered to
the adjacent omentum, transverse colon, and liver parenchyma cholecystectomy, atypical
hepatic segmentectomy of segments IVb, and V, and segmentary resection of the transverse
colon were done due to adhesions between the gallbladder and surrounding organs ([Fig. 5]). The specimen was sent to the department of pathology for histopathological examination.
Fig. 5 Gross pathology. Surgical piece that included cholecystectomy, atypical hepatic segmentectomy
of segments IVb and V, and segmentary resection of the transverse colon. Thickened
gallbladder wall (arrow), liver (star), and colon (asterisk).
The hematoxylin and eosin (H&E)-stained section from the gallbladder showed proliferating
or reactive lymphoid follicles with prominent germinal centers along with chronic
inflammatory infiltrate comprising lymphocytes, histiocytes, eosinophils, and plasma
cells underlying the lamina propria throughout the thickness of the gallbladder wall.
There was no necrosis, atypical cells, and xanthomized histiocytes. This tissue infiltrated
the liver parenchyma and adjacent colonic wall. Extensive areas of fibrosis were recognized,
forming dense septa that dissected and intermingled with the infiltrate areas. Liver
parenchyma showed portal spaces with chronic mononuclear inflammatory infiltrate and
stromal fibrosis ([Fig. 6]). Pathological diagnosis of CFC of the gallbladder with the liver and colon involvement
was made.
Fig. 6 Histopathology. H&E 100x show gallbladder wall with intraparietal lymphoid accumulations
(arrows). H&E, hematoxylin and eosin.
The postoperative course was uneventful and the patient was discharged 10 days after
surgery.
Discussion
CFC is a very rare benign entity with only a few cases published in the literature.[2]
[3] It represents less than 2% of cholecystectomies.[1]
[4] CFC has been mentioned as lymphoid hyperplasia, pseudolymphoma, and chronic cholecystitis
with lymphoid hyperplasia. It was first described on cholecystograms by Estrada et
al[5] in 1960. Being a highly uncommon pathology, the literature reports different opinions
about this entity.[6] It is characterized by hyperplastic lymphoid follicles with germinal centers consisting
of polymorphous lymphoid populations.[7]
[8] For the diagnosis, an increase in the number of intraepithelial lymphocytes per
100 biliary cells above the normal proportion of three to four lymphocytes is needed.[9]
The pathogenesis of CFC is unclear although it may be caused by an immune reaction
to luminal agents of the gallbladder.[10] Other theories include an autoimmune-mediated disorder in other areas of the gastrointestinal
tract or gram-negative bacterial infection that induce a lymphocytic reaction, such
as E. coli, K. pneumoniae, or S. typhi.[9]
[10]
[11] This inflammatory pattern can be encountered in other parts of the gastrointestinal
tract such as the esophagus, stomach, duodenum and colon, and in the orbits and lungs.[8]
Risk factors for developing CFC are unclear because there are uncertain causal associations.
It seems to affect more frequently middle-aged or elderly females, and other conditions
such as chronic hepatitis, thyroiditis, or primary biliary cirrhosis can coexist.[8] Differential diagnoses arise mainly between XGC and gallbladder carcinoma. XGC is
an unusual variant of chronic cholecystitis that is characterized by a lipid-laden
inflammatory process that can invade neighboring structures and can be blended with
cancer. Moreover, it is a challenging diagnosis as there are imaging similarities
between XGC and gallbladder cancer such as the enhancing and thickened wall, and the
tendency to involve neighboring organs.
Findings such as intramural hypoattenuated nodules occupying 60% of the area of the
thickened wall, intact enhancing mucosal lining, absence of biliary tract dilatation,
no large masses, and absence of lymph nodes suggest a diagnosis of XGC instead of
cancer.[12]
In our case, the gallbladder had diffuse parietal thickening, intramural nodules with
elevated T2WI signal intensity, and preservation of linear mucosal enhancement, similar
to an XGC. However, the intramural nodules did not show signal fall on opposed-phase
images as in XGC. It must be taken into account that although they share epidemiological
characteristics regarding age and sex, XGC does not present a clear association with
gallbladder cancer,[13] even though metaplastic changes can be found in up to 75% of patients with CFC.
However, its relationship with gallbladder carcinogenesis is unclear too.[1] In our case, no metaplastic changes were found.
We found no report regarding the adhesions and fibrosis to the liver and colon in
CFC. As CFC is thought to be caused by an immune reaction, chronic gallbladder inflammation
may induce a progressively irreversible fibrotic response that can affect surrounding
tissues. The surrounding fatty tissue had a high signal intensity on the T2-weighted
and fat-suppressed images, and the liver parenchyma adjacent to the gallbladder showed
enhancement at the arterial phase, both representing the inflammatory changes. We
had no previous imaging examinations to determine when these changes started.
Sometimes, the difficulty to distinguish XGC from gallbladder carcinoma derives from
extensive surgical resections. It is important to consider CFC as a differential diagnosis,
and in some cases perform a frozen section of the gallbladder to arrive at a correct
diagnosis and avoid wider surgical resections.
