Pancreatic Hydatid Cyst Causing Acute Pancreatitis: A Case Report and Literature Review

Hydatidosis is a public health problem in endemic countries. Hydatid cysts are located usually in the liver and the lungs. Primary pancreatic hydatid cyst is in unusual location and rarely causes acute pancreatitis. In this paper, we report a case of a 34-year-old man who admitted with recurrent acute pancreatitis. Following the preoperation investigations, the primary impression was a pancreatic pseudocyst. During surgery, a primary hydatid cyst was detected in the pancreas measuring 35 × 20 × 15 cm. The treatment consisted of evacuation and external draining of the cyst. In addition, we summarized 14 cases of primary hydatid cyst of the pancreas associated with acute pancreatitis reported in the literature.


Introduction
Echinococcosis, hydatid disease, and hydatidosis are alternative names of a zoonotic parasitic disease caused by the tapeworm Echinococcus. It is endemic in Mediterranean countries, the Middle East, South America, and the Indian subcontinent [1][2][3]. Four types of Echinococcus lead to infection in humans; Echinococcus granulosus is the most common parasite causing cystic echinococcosis with larval stage that represents more than 95% of cases [4]. It can infest various organs, and the invasion to the liver and lungs accounts for 90% [5]. Other involved sites are the muscles, bones, kidneys, brain, spleen, and pancreas. Pancreatic localization is a rare situation of hydatidosis representing 0.2% of cases [6].
Acute pancreatitis is commonly associated with alcohol intake or disorders of the pancreaticobiliary tracts [7]. Acute pancreatitis has rarely been reported due to a hydatid cyst of the pancreas [8]. Only 14 cases were reported in literature.
We report a case of hydatid cyst diagnosed after acute pancreatitis episode, and we reviewed and summed the data from other reported cases of hydatid cyst manifested as acute pancreatitis in the English and French literature.

Case Presentation
A 34-year-old man was admitted to the Surgery Department in our centre in July 2016 with di use abdominal pain, dyspnea, general fatigue, and weakness. In his medical history, he had been admitted to another centre two months ago for an episode of acute pancreatitis.
Abdominal ultrasonography revealed a heterogeneous area of 5 cm in size in the body of the pancreas, peripancreatic uid, gallstones with thickness in the gallbladder wall, and multiple cysts in the left kidney. Abdominal computed tomography (CT) showed heterogeneous collection of uid with a thick wall of 12 × 4 cm in size along the body of the pancreas and left colic angle (often an abscess or a pseudocyst) with in ltration of adipose tissue around it and mild thickness at the wall of the colon. A simple renal cyst was also reported in the left kidney ( Figure 1).
Laboratory investigations were within normal levels except an elevation in C-reactive protein value (18.1 mg/dl) and amylase (765 U/L). e hepatic tests were within the normal range (total bilirubin (TB) was 0.64 mg/dl, alanine aminotransferase (ALT) was 20 IU/L, and aspartate transaminase (AST) was 19 IU/L). e patient was treated as an episode of acute pancreatitis.
Other investigations were performed; upper gastrointestinal endoscopy (UGI endoscopy) demonstrated an esophagitis (grade A) at the lower esophagus, incompetence of the lower esophageal sphincter (LES), di use congestion of the mucous membrane of the stomach, and aphthous ulcer at the fundus of the stomach. Lower GI endoscopy was normal until the terminal ileum.
A month later, the CT scan for thorax and abdomen data were similar to the previous nding, and the pancreatic cyst measuring 13.5 × 7 cm stretched down through the peritoneal cavity in front of the mesenteric vessels.
e laboratory values were normal, and a primary diagnosis of pancreatic pseudocyst was probable, and the decision of surgical intervention was decided.
Intraoperatively, an extreme oedema in the pylorus, the transverse mesocolon, the head and body of the pancreas, and the hepatoduodenal ligament was found. A cholecystitis required cholecystectomy. After entering the lesser sac, a large mass of 35 × 20 × 15 cm in size was found, located in the space between the tail of the pancreas, spleen, left colic angle, left kidney, stomach, and diaphragm. e mass was hard to dissect from the neighboring structures. In puncture, a clear pure liquid was aspirated proposing the existence of a hydatid cyst. Cyst fenestration was performed, and multiple daughter cysts were evacuated; the endocyst membrane was removed ( Figure 2). A Foley catheter was placed in the residual cavity. e simple renal cyst needs no intervention according to the urologist. e nal diagnosis was pancreatic hydatid cyst. e patient had another episode of acute edematous pancreatitis after a month of surgery, and the amylase level was over 1000 U/L. e development of local retroperitoneal abscess required puncture and drainage by CT; the patient also developed a deep venous thrombosis and was treated by anticoagulants.
During 18 months of follow-up, the patient was well with no episodes of recurrence or other complications.

Literature Review
Besides our case, 14 cases of a pancreatic hydatid cyst with acute pancreatitis were reported. ree of them are available with abstract and one is not accessible. e ratio of women to men was 3/10. e mean age of the patients was 30.2 years. e location was solitary in the pancreas in 10 patients. e cyst was found in the body (7.1%), tail (28.5%), body and tail (21.4%), or head (28.5%) ( Table 1).
On clinical examination, no speci c complaints or signs were found to distinguish hydatid cyst from other etiology of acute pancreatitis so that the nal diagnosis was made preoperatively in 4 cases by ultrasonography or computed tomography. In our case, the nal diagnosis was made intraoperatively.
Laboratory investigations varied between cases, and they were not available in all cases. e average of white blood cells was 17,943/mm 3 , and the amylase median was 1718 U/L. Surgical procedures that have been carried out varied according to every situation; for example, left pancreatectomy with splenectomy was performed in 5 cases. Only 2 patients were treated with albendazole before surgery.
After surgery, there were some complications such as external pancreatic stula (n � 1), complex pancreatic stula (an external and enterocutaneous stula between the transverse colon and the skin surface), and portal vein thrombosis (n � 1). Fistulae were treated with parenteral nutrition, antibiotic therapy (ampicillin), and adequate local treatment. e mean follow-up was 25 months without recurrence or other complications (missing value � 6) ( Table 2).

Discussion
Hydatid cysts can localize virtually in any organ and structure of the body. e highest rate of cysts location exists in the liver and the lungs, which assess to 70% and 20% of patients, respectively. Other organs present in a small proportion of patients [21,22]. It is rarely detected in the pancreas.
According to a previous review in 2012 [17], the cyst is single in the pancreas in 90% of the cases. Moreover, 50% of the cysts can be located in the head, 24-34% in the body, and 16-19% in the tail. e clinical manifestations of cystic echinococcosis (CE) depend on the size of the cyst, site, and potential complications such as rupture, compression on adjacent tissue or organs, infections, and intestinal or biliary stula [23]. Hepatic hydatid cysts rupture into the biliary tree in 5-17% of the cases [24]. is complication is rarely associated with acute pancreatitis [25,26]. Hepatic hydatid cysts can also compress the biliary tract [27]. In accordance with that, we can say that the pancreatic hydatid cysts may compress Wirsung's duct or rupture into it, which produces acute pancreatitis.
Diagnosis of cystic hydatidosis is based on imaging. Ultrasonography allows classi cation of the cysts, as the WHO classi cation tabulates cysts in 3 groups: the rst one is active and includes CE1, which appears as unilocular anechoic cystic lesion with double-line sign, and CE2, which is a multiseptated "rosette-like" "honeycomb" cyst; the second one is transitional and contains CE3a cyst with detached membranes (water-lily sign) and CE3b cyst with daughter cysts in the solid matrix; and nally, the third group is inactive and has CE4 and CE5 cysts with heterogeneous hypoechoic/hyperechoic contents and no daughter cysts and solid plus calci ed wall [28].
CT scan demonstrates the features of hydatid cysts better than US. CT scan can identify the number, size, shape, margins, anatomic location, and calci cation. Furthermore, the abdominal CT scan may be used to evaluate complications like rupture into the main pancreatic duct. It also assesses the lesions during therapy [16]. Magnetic resonance imaging (MRI) has a role in detecting the characters of the cysts and complications better than CT; however, MRI is usually not desired because of its cost [21]. e management of the cystic echinococcosis (CE) includes surgery, percutaneous treatment, antiparasitic drug therapy, and observation [29]. Surgery is the classic approach to treat CE, and it is appropriate for complicated cysts and in cases for which percutaneous treatment is not available [29]. Evacuation of the cyst and defacement of the residual cavity are the aims of the surgical therapy [30].  PAIR (puncture, aspiration, injection of a scolicidal agent, and reaspiration) is one technique of percutaneous treatment used as a therapeutic and diagnostic option that counts as an effective replacement to surgery with lower rates of recurrence and mortality [28]. Medical therapy is useful when it is combined with/to surgery and percutaneous therapy. Drug treatment before and after the procedure reduces the risk of recurrence. e rst medication to be used is mebendazole and then there were albendazole and praziquantel. Albendazole is the most e ective [11].