Intestinal obstruction from CSF pseudocyst mimicking mesenteric cyst in a shunted child with hydrocephalus: a rare presentation

Background: Ventriculoperitoneal (VP) shunting is a standard treatment for congenital hydrocephalus but carries potential complications, including cerebrospinal fluid (CSF) pseudocyst formation. Intra-abdominal CSF pseudocysts are uncommon, particularly in infants, and may present with atypical features, such as intestinal obstruction. On imaging, they can closely mimic mesenteric or enteric cysts, making diagnosis challenging. Case presentation: Herein, we present a 1-year-old female with congenital hydrocephalus who underwent VP shunt placement soon after birth. She presented with progressive abdominal distension, bilious vomiting, poor feeding, fever, and lethargy. Examination revealed a tense abdomen; imaging demonstrated a large intra-abdominal cystic mass obscuring the VP shunt tip and compressing adjacent bowel loops. Laboratory results showed severe anemia (Hb 6 g/dL) and hypokalemia (K⁺ 2.9 mmol/L). Exploratory laparotomy revealed a CSF pseudocyst tightly adherent to the small bowel with associated torsion. Complete cyst excision was performed, and the VP shunt was removed and replaced with an external ventricular drain. Postoperative recovery was uneventful. Discussion: CSF pseudocysts are rare but important complications of VP shunts, often resulting from infection, inflammation, or shunt malfunction. Presentation can vary from vague abdominal symptoms to acute obstruction. This case is notable for bowel torsion and severe anemia, an unusual combination in pediatric pseudocyst cases. Misdiagnosis as a mesenteric cyst can delay appropriate neurosurgical intervention. Conclusion: In shunted children presenting with abdominal distension or obstruction, a CSF pseudocyst should be considered. Prompt recognition, appropriate imaging, and timely surgical management are essential to prevent serious morbidity and mortality. Multidisciplinary collaboration between pediatric surgeons and neurosurgeons optimizes outcomes.