Gallbladder fossa lymphangioma encasing the common bile duct: a case report and review of the literature

Introduction: Lymphangiomas are rare low-flow lymphatic vessel malformations mostly diagnosed in childhood. Among the abdominal lymphangiomas, the gallbladder lymphangioma is a rare presentation, and only a few cases have been reported till date, of which majority were cystic lymphangiomas. Case presentation: The authors present a case of a 48-year-old female with abdominal pain and normal physical examination and laboratory findings. On the performed imaging, a multiloculated cystic lesion, located in the gallbladder fossa, was found. The patient underwent open cholecystectomy, and surprisingly, the cyst extended to the common bile duct, which was separated cautiously. The cyst was resected, and the histopathological findings confirmed cystic lymphangioma. Conclusion: The cystic lymphangioma of the gallbladder can be asymptomatic, although most of the literature has reported abdominal pain. The diagnosis of lymphangioma is complicated, especially when intra-cystic hemorrhage happens. Ultrasonography, computed tomography, and magnetic resonance imaging are usually performed. The surgical excision of the cyst and the gallbladder is the treatment of choice. Although bile duct involvement is extremely rare, it should be considered during the surgery.


Introduction
Lymphangioma, with an incidence rate of 1:2000-4000 in children, is a common benign lymphatic vessel lesion in childhood, affecting both genders equally.Most of the cases are diagnosed before the age of two, and the presentation of the lesion in adulthood is rare.Lymphangioma is commonly located in the head and neck (70-80%) but can present in rarer sites, including the lungs, pleura, pericardium, and gastrointestinal tract.Among intraabdominal lesions, gallbladder lymphangioma is extremely rare and usually overlooked until it grows to a large mass, resulting in abdominal discomfort [1][2][3] .We represent a large cystic lymphangioma of gallbladder fossa encasing the common bile duct (CBD) and the gallbladder.

Case presentation
A 48-year-old female was referred to our department complaining of intermittent abdominal pain for 2 years.The non-positional pain was colicky, with gradual onset limited to the epigastric area and the right upper quadrant, with no relevance to defecation, eating, and breathing.There were no associated symptoms.The patient had a history of hypertension herself and hepatic cancer in her father.She has been taking oral contraceptives for the past 10 years.A month before our visit, an endoscopy and rapid urease test were performed, and no abnormal findings were revealed.On physical examination, the patient was afebrile, with normal vital parameters.In the laboratory results, there was no abnormal finding.The ultrasonography (US), obtained right after the presentation, revealed a large, well-circumscribed multilocular cystic mass with dimensions of 10.6 × 9.2 × 12.4 cm, having multiple, thin septa and no solid component located in the gallbladder fossa (Fig. 1).Suspecting a hydatid cyst, we measured an anti-hydatid antibody, and the result was negative.A week later, the computed tomography (CT) with contrast demonstrated a normal gallbladder.A large cystic lesion with scalloping borders measuring approximately 11.6 × 9 × 11 cm (550 cc) in the gallbladder fossa with left lateral extension up to the left subhepatic space and inferior expansion to level of the D2 segment of the duodenum was seen (Fig. 1).No typical feature of hydatid cyst was detected, and the cyst had completely encased the gallbladder and a tiny branch of the proper hepatic artery.Based on the findings, the cyst was diagnosed as a gallbladder lymphangioma.Without further imaging, after a few days, the patient underwent an open cholecystectomy with a Chevron incision.Opening the abdomen, the large cyst filled with fluid was seen, lying beneath the liver   adherent to the left liver lobe, stomach, and gastrohepatic and hepatoduodenal ligaments (Fig. 2).The gallbladder and the CBD were encased by the cyst.The cyst and gallbladder were both successfully resected.Due to adhesion, the CBD was cut; an endto-end anastomosis of the CBD was created without any complications, and a drain was inserted.No evidence of recurrence on the third month follow-up was noted.Microscopic sections of the received specimen demonstrated small to large caliber vascular spaces, lined by endothelial cells, which were filled with eosinophilic proteinaceous fluid and intraluminal clusters of lymphocytes (Fig. 2).Cytological examination of cyst-like drained fluid revealed numerous lymphocytes, and the diagnosis of cystic lymphangioma was confirmed.

Discussion
Lymphangioma is an infrequent nonmalignant malformation of the lymphatic vessels.This lesion is categorized as simple, cavernous, and cystic types based on the histological characteristics.The simple type is mostly located on skin, while the cavernous and cystic types are mainly deep in the body.In contrast to cystic type, in cavernous lymphangioma, there is a connection between dilated lymphatic spaces and the normal adjacent lymphatic vessels.Abdominal lymphangiomas can be seen uncommonly, and among them, gallbladder lymphangioma is very rare [2][3][4] .There are several theories corresponding to the etiology of these lesions, indicating the role of external factors like abdominal surgery, trauma, radiation, and any other cause that can interrupt the normal lymphatic drainage [4] .A PubMed search using the MeSH terms "Lymphangioma" and "Gallbladder" was conducted.We studied the articles reporting cases of cystic or cavernous lymphangioma of gallbladder regardless of age, sex, and presence of the symptoms.The inclusion criteria were case reports written in English presenting patients admitted with gallbladder lymphangioma.Papers in languages other than English and article types other than case reports were excluded.The final analysis included 15 articles published between 1995 and 2023.
Although early studies have not reported any predisposing factors in the family history or past medical history, our case had a history of hepatic cancer in her father, and the probable correlation is still unstudied.Reported cases of gallbladder lymphangioma are mainly women, and the age varies from 2 to 66 (Table 1) [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] .Although lymphangioma can be an incidental finding [4][5][6]9,13,15] , at the time of presentation, most of the cases had symptoms including chronic or acute right upper quadrant pain as a result of the compression effect of the cyst [3,8,10,12,[14][15][16][17] . Intra-cytic hemorrhage occurred in some cases and made the lesion harder to diagnose [4,6,12] , while no rupture of the cyst is reported.Diagnosing gallbladder lymphangioma is mostly based on imaging, and the laboratory results and abdominal examination were normal in most of the cases.While US shows a simple or multilocular mass filled with anechoic fluid, complementary CT demonstrates a cystic lesion with the same density as water and uniform septal thickness [9] .Magnetic resonance imaging (MRI), magnetic resonance cholangiopancreatography (MRCP), and endoscopic retrograde cholangiopancreatography (ERCP) are widely used to receive additional information about the lesion vicinities and communication to the biliary tract.In an MRI performed in the axial and coronal planes, typical findings include a simple or multiloculated cystic lesion without any solid component, and in some cases, the septa of the cyst are enhanced [9,14] .MRI is also helpful to differentiate between intra-cystic solid mass and intra-cystic hemorrhage, while CT may be less efficient if the case is initially presented after hemorrhage [4] .In a particular case in addition to the imaging mentioned above, an abdominal angiography was performed preoperatively showing avascular cystic lesion receiving a branch of cystic artery [5] .The multiseptated cystic mass originating from the gallbladder fossa can replace, encase [8,] or encapsulate [4] the gallbladder.Similar to our case in which the CBD was encased by the lesion, a previous study reported a gallbladder lymphangioma encasing the entire extra-hepatic bile ducts [8] . Considering all he available imaging, gallbladder lymphangioma can be misdiagnosed due to its rare presentation and possible complications, namely intra-cystic hemorrhage or inflammation.A number of authors have indicated simultaneous lymphangioma and microlithiasis [10] , asymptomatic cholelithiasis [9,] or acute cholecystitis [12,14,] which made the diagnosis more complicated.The cyst was also misdiagnosed as hydatid cyst. To overcme the diagnostic problems, five out of 16 cases underwent exploratory laparotomy [3,8,9,13,15] .All early studies have suggested laparoscopic or open resection of the mass with the gallbladder as the treatment of choice in gallbladder lymphangioma, and no conservative management has been reported.In one study mentioned earlier, due to bile duct involvement, the extra-hepatic bile ducts were also resected en bloc, and Roux-en-Y choledochojejunostomy was done [8] .None of the authors acknowledged any recurrence after surgery.Histopathology examination of resected masses confirmed cystic lymphangioma of the gallbladder in 14 out of 16 cases, and the two remainder were acknowledged as the cavernous type.The microscopic findings in a cystic lymphangioma include presence of lymphocytes, variable lymphatic spaces lined by flat endothelium, and smooth muscles in cyst walls, while in the cavernous lymphangioma, no smooth muscle is seen [5,16] .Only few works in literature mentioned using immunohistochemistry tests such as D2-40 staining [10,14] .

Conclusion
Despite the fact that gallbladder lymphangioma is rare, it is considerable in patients with right upper quadrant (RUQ) pain, tenderness, palpable mass, and associated symptoms.US, CT, and MRI are usually used to assess the suspected lesion.However, MRCP and ERCP may be essential for a close observation on biliary tree.The gold standard treatment is the excision of the cyst and gallbladder.As experienced in our case, the CBD may be involved, which should be preserved delicately.

Patient perspective
On follow-up sessions, she was totally satisfied with the result of the treatment.The patient experienced a complete remission with no recurrence of symptoms or any complaints related to the surgery.

Ethical approval
Ethical approval for this study was provided by the Research Ethics Committees of Guilan University of Medical Sciences, Rasht, Iran, on 10 January 2024.The approval ID is IR.GUMS.REC.1402.515.

Figure 1 .
Figure 1.(A) A large multilobulated cystic lesion in ultrasonography is shown.(B) Abdominal computed tomography demonstrates a large lobulated non-enhancing wall cystic lesion in gallbladder fossa.

Figure 2 .
Figure 2. (A) A large cystic lymphangioma encasing the gallbladder is shown.(B) Intraoperative picture taken following mass resection, and anastomosis of the common bile duct.(C) The red arrow shows thin-walled, dilated lymphatic channels without intraluminal proteinaceous material and lymphocytes.The green arrow points to lymphocyte aggregation.(D) Bland, flat endothelial cells are marked.

Table 1
Summary of gallbladder lymphangioma cases presented in the literature.