The treatment of hydrocephalus is based on diverting cerebrso spinal fluid (CSF) into different body cavities; and peritoneum is still the most reliable and the most used place. The ventriculoperitoneal (VP) shunt-induced abdominal pseudocyst is a rare complication in patients with VP shunt which was first described by Harsh in 1954 [1]. Intestinal obstruction, intestinal perforation, peritonitis, abscess, bladder perforation and pseudocyst are the main abdominal complications of VP shunts. Pseudocyst occurence rates are reported to be between 1 and 3%, and there are only limited number of cases of VP shunt-induced hepatic pseudocyts in the literature [2, 3]. We report two cases of VP shunt induced extrahepatic pseudocyst patients with different backgrounds.

Abdominal pseudocysts are a rare VP shunt complication. It is characterized with a cystic mass encircled with a fibrous wall with CSF and the shunt catheter inside [4]. One of the theories about the abdominal pseudocyst etiology is the inflammation theory, which proposes the main reason as recurrent infections, shunt revisions, intestinal adhesions and peritonitis [5]. Furthermore, it is suggested that the allergic reactions and CSF oncotic pressure elevation due to high protein levels may help pseudocyst formations. Hepatic pseudocyst secondary to a VP shunt is a rarely a reported complication [3, 6]. During the abdominal catheter implantation, damaging Glisson’s capsule with shunt can cause subhepatic - extrahepatic pseudocysts. Similarly, penetrating hepatic parenchyma with the shunt catheter can cause intra hepatic pseudocyts [7].

The most common symptoms caused by abdominal pseudocyst are abdominal pain (63%), abdominal distension (37%), tenderness (31%) and abdominal mass (29%). In pediatric patients, abdominal pseudocysts are mostly presented with the symptoms caused by the elevated intracranial pressure; on the other hand, adult patients are usually presented with abdominal symptoms. There are also cases presented with both symptoms, as ours [2, 8].

Main pathologies in differential diagnosis with abdominal pseudocysts are mesenteric or omental cysts, duplication cysts, Iymphocele, cystic teratoma, cystic lymphangioma, pancreatic pseudocyts, abscess and bilomas. It is suggested that abdominal USG and radiography are sufficient for diagnosis, but to determine the exact location, size of the cyst, and the location of the shunt catheter; also to exclude other acute abdominal syndrome reasons, abdominal CT is reported as more valuable [2, 4, 6, 8]. Typically, on extrahepatic pseudocyst cases, CT scan reveals a parenchyma free capsule formation with smooth margin extending out from the liver and isodense cyst content with CSF [6, 8, 9]. Cytological examination of cyst ingredient is essential for the final diagnosis.

Treatment options for abdominal pseudocysts are still on debate. General approach is, the removal of the catheter (with or without the removal of the cyst) and sending the catheter to a different quadrant. Aspiration of pseudocyst, laparoscopic cyst excision and laparoscopic shunt installation are a few other suggested treatment modalities [6]. In literature, it is seen that laparoscopy procedures are favored in the recent years [10]. In the presence of an infection, it is suggested that implanting an external ventricular drain and installing a new shunt after appropriate antibiotherapy and seeing CSF is sterile [2, 4, 8]. In our cases we saw that, sending the catheter to a different quadrant, without excision of the pseudocysts, is sufficient. In follow-ups, we observed that the pseudocysts regressed spontaneously after the catheter removal in both of the patients. No recurrence were observed. When we examine closely with laparoscope, as in our first case, we encountered no adhesion between catheter and cyst wall during the removal.

In the first case that was performed laparoscopically, after removal of the shunt catheter, the cyst content was drained spontaneously. During the dissection of the cyst, because of the adhesions, we considered the possibility of liver contusion and decided to leave the cyst. For this reason in the second case, we only removed and replaced the shunt catheter and it was sufficient for the regression of the cyst. When it is certain that the pseudocyst etiology is dependant to the shunt, intra abdominal intervention is not always necessary (laparoscopic or not). Diverting the distal tip of the shunt to a different intra abdominal region is seen to be enough. In cases with persisting distal catheter dysfunction, ventriculo-atrial shunt should also be considered.

Although it is rare, VP shunt-induced intraabdominal CSF pseudocysts may occur in every shunt patient. When a VP shunt patient admit us with non-specific abdominal symptoms, the possibility of this complication should always be kept in mind. In the treatment of this complication, it is shown that repositioning the catheter is sufficient for cyst regression. However, it is vital that observing and discussing more cases are essential for truly understanding this complication. Furthermore, the evaluation of shunt patients with every abdominal complication is important in terms of understanding the possible factors in etiology and overcoming the difficulties in clinical and surgical management of VP shunt patients with abdominal complications.