125 * Corresponding author, Phone: 81-298-53-3205, Fax: 81- 298-53-3205, E-mail: ytanakamd.tsukuba.ac.jp 125 Magnetic Resonance in Medical Sciences, Vol. 1, No. 2, p. 125–128, 2002 CASE REPORT Adenomyomatosis with Marked Subserosal Fibrosis and Lipomatosis of the Gallbladder: Mural Stratiˆcation Demonstrated with MR Yumiko OISHI TANAKA 1 *, Tetsuo HORI 2 , Michio NAGATA 3 , and Yuji ITAI 1 1 Department of Radiology, Institute of Clinical Medicine, University of Tsukuba 2 Department of Pediatric Surgery, Institute of Clinical Medicine, University of Tsukuba 3 Department of Pathology, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan (Received February 26, 2002; Accepted May 8, 2002) The authors reported a case of fundal-type adenomyomatosis in which mural stratiˆca- tion corresponding to histopathological ˆndings was clearly demonstrated with MR imag- ing. Single-shot fast spin echo images for MR cholangiopancreatography clearly visualized Rokitansky-AschoŠ sinuses (RAS), which are a diagnostic clue for this disease. However, mural stratiˆcation comprising RAS with muscular proliferation, massive ˆbrosis and sub- serosal fat deposition was more precisely demonstrated in T 2 -weighted images obtained with fast spin echo. Keywords: gallbladder-MRI, gallbladder-adenomyomatosis, Rokitansky-AschoŠ sinus Case Report A 14-year-old girl with abdominal pain was referred to our hospital. She complained of right hypochondralgia after meals, which began more than two years earlier. The frequency of the pain had been increasing for the past several months, prompting her to visit another hospital. Using MR cholangiopancreatography (MRCP), a pediatrician at that hospital suspected choledochal cyst, which is characterized by dilation of the upper portion of the common bile duct. The pediatrician referred her to the department of pediatric surgery of our hospital. During her ˆrst visit to our outpatient clinic, a routine laboratory examination that included white blood cell counts, C-reactive protein and other en- zymes related to biliary tract indicated no abnor- mality. Physical examination revealed a mass 3 cm in diameter. MR imaging was performed with a 1.5T superconducting unit (Gyroscan Intera, Philips, Best, The Netherlands) followed by CT. Axial T2-weighted images (T2 WI) with fast spin echo (FSE), balanced turbo ˆeld echo (BTFE) in the axial and coronal planes and heavily T2-weight- ed images with single-shot fast spin echo (SSFSE) for MRCP in the oblique coronal plane were per- formed. MR revealed localized thickening of the fundal wall of the gallbladder. The thickened wall demonstrated ˆve-layered stratiˆcation on T2 WI (Fig. 1); the innermost zone surrounding the gallbladder cavity showed a thin hypointense band; the second zone demonstrated a slightly hyperin- tense area with an indistinct margin and scattered hyperintense foci; the third zone showed a hypoin- tense band far thicker than the innermost zone; the fourth zone was as hyperintense as intraabdominal fat tissue; and the outermost zone was a thin hypointense band. BTFE also visualized mural stratiˆcation (Fig. 2), and MRCP obtained with SSFSE clearly visualized small hyperintense nod- ules surrounding the cavity within the thickened gallbladder wall (Fig. 3). Although the maximum diameter of the common bile duct was 9 mm, it smoothly tapered without any signal defects. As the length of the common channel was less than 4 mm, we did not diagnose long common channel syn- drome. Therefore, our pre-surgical imaging diag- nosis was fundal-type adenomyomatosis of the gallbladder; mild dilatation of the common bile duct was considered as an accompanying ˆnding. Laparoscopic cholecystectomy was performed about a month after MR imaging. No particular abnormality or adhesion to the surrounding tissue was noted on the laparoscopy. The resected gallbladder was markedly enlarged, measuring 19.5 5.53 cm (Fig. 4). The cut surface of the speci-
Magnetic Resonance in Medical Sciences, Vol. 1, No. 2, p. 125–128, 2002
CASE REPORT
Adenomyomatosis with Marked Subserosal Fibrosis and Lipomatosis ofthe Gallbladder: Mural Stratiˆcation Demonstrated with MR
Yumiko OISHI TANAKA1*, Tetsuo HORI2, Michio NAGATA3, and Yuji ITAI1
1Department of Radiology, Institute of Clinical Medicine, University of Tsukuba2Department of Pediatric Surgery, Institute of Clinical Medicine, University of Tsukuba
3Department of Pathology, Institute of Clinical Medicine, University of Tsukuba,1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
(Received February 26, 2002; Accepted May 8, 2002)
The authors reported a case of fundal-type adenomyomatosis in which mural stratiˆca-tion corresponding to histopathological ˆndings was clearly demonstrated with MR imag-ing. Single-shot fast spin echo images for MR cholangiopancreatography clearly visualizedRokitansky-AschoŠ sinuses (RAS), which are a diagnostic clue for this disease. However,mural stratiˆcation comprising RAS with muscular proliferation, massive ˆbrosis and sub-serosal fat deposition was more precisely demonstrated in T2-weighted images obtainedwith fast spin echo.
A 14-year-old girl with abdominal pain wasreferred to our hospital. She complained of righthypochondralgia after meals, which began morethan two years earlier. The frequency of the painhad been increasing for the past several months,prompting her to visit another hospital. Using MRcholangiopancreatography (MRCP), a pediatricianat that hospital suspected choledochal cyst, whichis characterized by dilation of the upper portion ofthe common bile duct. The pediatrician referredher to the department of pediatric surgery of ourhospital.
During her ˆrst visit to our outpatient clinic, aroutine laboratory examination that included whiteblood cell counts, C-reactive protein and other en-zymes related to biliary tract indicated no abnor-mality. Physical examination revealed a mass 3 cmin diameter. MR imaging was performed with a1.5T superconducting unit (Gyroscan Intera,Philips, Best, The Netherlands) followed by CT.Axial T2-weighted images (T2WI) with fast spinecho (FSE), balanced turbo ˆeld echo (BTFE) inthe axial and coronal planes and heavily T2-weight-ed images with single-shot fast spin echo (SSFSE)for MRCP in the oblique coronal plane were per-
formed. MR revealed localized thickening of thefundal wall of the gallbladder. The thickened walldemonstrated ˆve-layered stratiˆcation on T2WI(Fig. 1); the innermost zone surrounding thegallbladder cavity showed a thin hypointense band;the second zone demonstrated a slightly hyperin-tense area with an indistinct margin and scatteredhyperintense foci; the third zone showed a hypoin-tense band far thicker than the innermost zone; thefourth zone was as hyperintense as intraabdominalfat tissue; and the outermost zone was a thinhypointense band. BTFE also visualized muralstratiˆcation (Fig. 2), and MRCP obtained withSSFSE clearly visualized small hyperintense nod-ules surrounding the cavity within the thickenedgallbladder wall (Fig. 3). Although the maximumdiameter of the common bile duct was 9 mm, itsmoothly tapered without any signal defects. As thelength of the common channel was less than 4 mm,we did not diagnose long common channel syn-drome. Therefore, our pre-surgical imaging diag-nosis was fundal-type adenomyomatosis of thegallbladder; mild dilatation of the common bileduct was considered as an accompanying ˆnding.
Laparoscopic cholecystectomy was performedabout a month after MR imaging. No particularabnormality or adhesion to the surrounding tissuewas noted on the laparoscopy. The resectedgallbladder was markedly enlarged, measuring 19.5�5.5�3 cm (Fig. 4). The cut surface of the speci-
126
Fig. 1. This axial T2-weighted image (fast spin echowith sensitivity encoding, TRWTE: 1600W90 ms,6 mm slice thickness with 0.6 mm intersection gap,16 echo train length, 28 cm ˆeld of view, four excita-tions, 256�512 matrix with zero ˆll interpolation,reduction factor of 2) demonstrates ˆve-layeredmural stratiˆcation of the gallbladder, which showslow signal intensity (small asterisk), high signal inten-sity with marked hyperintense foci, low signal inten-sity (large asterisk), and high and low signal intensity(middle asterisk) from the inner.
Fig. 2. This coronal balanced turbo ˆeldecho image with sensitivity encoding (TRWTE:3.9W1.9 ms, 7 mm slice thickness with �3 mmintersection gap, 25 cm ˆeld of view, two exci-tations, 256�256 matrix and 1.5 reductionfactor) also demonstrates mural stratiˆcation.The Rokitansky-AschoŠ sinuses are visualizedmore precisely, although the contrast betweeneach layer is blurred compared with the T2-weighted images.
Fig. 3. MR cholangiopancreatography with3D single-shot fast spin echo and sensitivityencoding (TRWTE: 1600W650 ms, 110 echotrain length, 2 mm slice thickness with �1 mmintersection gap, 161�512 matrix with zero ˆllinterpolation and 1.5 reduction factor) visual-izes many Rokitansky-AschoŠ sinuses sur-rounding the cavity of the gallbladder fundus.
Fig. 4. The fundal wall of the resected gallbladderis markedly thickened (arrows).
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men showed ˆve-layered mural stratiˆcation corre-sponding to MR images (Fig. 5). The innermostzone seemed to correspond to the lamina mus-cularis mucosae. The second layer corresponded toa slightly hypertrophic muscular layer with out-pouching of the mucosa into the layer (Rokitansky-AschoŠ sinuses). Massive ˆbrosis with inˆltrationof several small round cells surrounded the hyper-trophic muscular layer. In the subserosal area,
127
Fig. 5. The thickened gallbladder wall comprisesRokitansky-AschoŠ sinuses with hypertrophic mus-cular layer (M), massive ˆbrosis (F) and subserosalfat deposition (L) (a, Hematoxylin-eosin stain, �1,original magniˆcation). Lamina muscularis mucosaecorresponding to the innermost hypointense layerand serosa corresponding to the outermost hypoin-tense layer are too thin to be indicated. Note theaberrant glandular tissue (arrow) within the muscularlayer, which characterizes this case as adenomyoma-tosis (b, Hematoxylin-eosin stain, �10, originalmagniˆcation).
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marked fat deposition was noted. The outermostzone seemed to be the serosa.
The patient's post-surgical course was uneventfuland she underwent follow-up in the outpatient clin-ic for two months. The abdominal pain disap-peared immediately after the surgery.
Discussion
Adenomyomatosis of the gallbladder is a rela-tively common disease characterized by epithelialproliferation and hypertrophy of the muscularis ofthe gallbladder, with outpouching of the mucosainto the thickened muscularis. Radiological diagno-sis of this disease had been established by visualiz-ing outpouching mucosa into the muscularis, which
is called Rokitansky-AschoŠ sinuses (RAS). Be-cause adenomyomatosis appears as both a diŠuseand focal (segmental and fundal) disease, it issometimes di‹cult to distinguish from gallbladdercarcinoma when it appears as a focal distribution.1
However, RAS cannot be observed in carcinoma orchronic cholecystitis, it seems to be a pathogno-monic imaging ˆnding of this entity.1 Oralcholecystography may reveal RAS if it maintains apatent communication with the lumen and if theRAS are large enough to create visible collectionsof contrast material adjacent to the lumen of theopaciˆed gallbladder.2,3 Ultrasound appearances ofadenomyomatosis had also been well described,including multiple comet tail artifacts.4 Recent ad-vances of spatial and temporal resolution in CThave enabled visualization of RAS.5 MR oŠers apotential advantage in diagnosing this entity be-cause of its excellent contrast resolution despiterespiratory motion and bowel peristalsis. Althoughdilated RAS has been visualized both with a dy-namic contrast study6 and T2-weighted MR images,recent advances in multi-element phased-array coilsand fast scanning techniques enable us to obtainmore precise MR images without the use of con-trast material.1,5,7
The RAS were clearly visualized on all sequencesthat we performed, especially heavily T2-weightedimages obtained for MRCP with SSFSE because ofthe thinner slice thickness. The relationship be-tween common hepatic ducts and cystic ducts wasalso easily evaluated in this sequence. As an exami-nation for surgical planning, this oŠers a signiˆcantadvantage, especially when laparoscopic surgery isscheduled. However, the mural stratiˆcation of thethickened gallbladder wall was blurred in this se-quence. In 1960, Jutras et al. advocated a conceptof hypertrophic cholecystoses.8 This is the genericterm for a group of abnormalities of the gallblad-der that appear apart from in‰ammatory disease.``Hypertrophic'' implies benign proliferation ofnormal tissue elements, whereas ``cholecystoses''indicates a pathologic process distinct fromin‰ammation. Jutras' classiˆcation included sevenspeciˆc changes, including adenomyomatosis,lipomatosis and ˆbromatosis.8 Berk et al. conclud-ed that adenomyomatosis is a variety of hyperplas-tic cholecystoses characterized by hyperplasia ofthe tissues of the gallbladder wall. They also be-lieved that seven speciˆc changes in Jutras' classiˆ-cation can overlap and have a common etiology.2
Miyake et al. reported subserosal fat proliferationin adenomyomatosis on CT.3 The cause of fatdeposition is unknown; such reports suggest thatfat deposition or massive ˆbrosis in lamina propria
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can sometimes occur in patients with adenomyoma-tosis. The resected specimen had a thick ˆbrous lay-er with inˆltration of a few small round cells justunder the RAS. T2WI with FSE demonstrated thisˆnding as the third layer with a low signal intensitycorresponding to ˆbrous tissue. It also demonstrat-ed subserosal fat deposition as the fourth hyperin-tense layer. This mural stratiˆcation has not beenreported in cases of gallbladder carcinoma; it maybe another clue for diŠerential diagnosis.9 In addi-tion, this mural stratiˆcation corresponds closely tothe histopathological ˆndings.
Wide use of ultrasonography has led to thediscovery of many patients with asymptomaticadenomyomatosis. However, abdominal painwithout calculi is common in the relatively olderreports.2,3 It is believed that excessive intraluminalpressure plays a role. The cause of the abdominalpain in the present case remained unknown, but thesymptom disappeared following the cholecystec-tomy. Mild dilatation of the bile or cystic duct hasbeen also reported in this entity, related to spasm ofthe sphincter muscle triggered by overextension ofthe RAS.10
In conclusion, we reported a case withadenomyomatosis of the gallbladder, in which MRprecisely demonstrated mural stratiˆcation corre-sponding to marked subserosal ˆbrosis and fatdeposition.
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