Peach pit impaction presenting as gallstone ileus

Abstract

Small bowel obstruction (SBO) secondary to fruit pit impaction is rare. The presence of an ovoid, stony body in the bowel lumen on radiologic imaging in a patient presenting with signs and symptoms of SBO is likely to raise concern for gallstone ileus. We report the case of a 56-year-old man who presented with a 1-day history of intermittent left-sided abdominal pain and nausea associated with a single episode of vomiting. CT scan of the abdomen and pelvis revealed a 3.3 cm impacted stony mass in the terminal ileum resulting in high-grade partial SBO. The mass had a hypodense centre encased within a hyperdense, ridged outer layer. The diagnostic impression was gallstone ileus. The object was removed via enterotomy and was found to be a peach pit.

Background

Small bowel obstruction (SBO) due to an intraluminal cause is uncommon. In an adult with no history of psychiatric illness presenting with SBO and a stony mass in the bowel lumen, a differential diagnosis is likely to place gallstone ileus higher than SBO due to fruit pit impaction. In this case, the diagnosis was only realised at surgery. Retrospectively reviewing the imaging, we noted certain features that were more consistent with fruit pit impaction rather than gallstone ileus. The authors feel that this case illustrates the importance of careful review of imaging before surgery and in the absence of the usual radiological findings, considering the possibility of aetiologies other than gallstone ileus when a patient presents with SBO due to an ovoid, stony foreign body within the small bowel.

Case presentation

A 56-year-old man presented to the emergency department with a 1-day history of intermittent left-sided abdominal pain and nausea associated with a single episode of vomiting. He had not had a bowel movement for the past 24 hours. He denied prior episodes and there was no significant medical or surgical history. On examination, he appeared well, his vital signs were normal and abdomen was non-tender but visibly distended. Palpation did not identify any abdominal masses or groin hernias. Bowel sounds were normoactive.

Investigations

Abdominal CT scan with intravenous contrast was obtained which demonstrated a 3 cm radiopaque lesion in the lumen of the distal ileum along with dilated proximal bowel and distal collapsed bowel, indicative of a high-grade partial SBO (figure 1). There was no evidence of pneumobilia or gallbladder wall thickening.

Figure 1.

Coronal (A) and axial (B) CT showing a 3 cm radiopaque lesion in the distal ileum (yellow arrows). Note the small bowel dilation (blue arrows).

Ultrasound of the right upper quadrant did not demonstrate any fistulas or gallstones. The patient’s white cell count was elevated at 14×10⁹/L and his haemoglobin was also elevated at 174 g/L. Serum electrolytes were unremarkable.

Differential diagnosis

The differential diagnosis included gallstone ileus and SBO secondary to foreign body impaction. Although the absence of pneumobilia and gallbladder wall thickening made gallstone ileus an unlikely possibility, it remained on the differential due to the radiological appearance of the lesion being mistaken for a gallstone.

Treatment

An enterolithotomy was planned via laparoscopy. Following entry into the abdomen, a small amount of serous fluid was noted in the peritoneal cavity. However, the procedure was converted to a laparotomy to better visualise the small bowel. Most of the small bowel appeared to be distended. The terminal ileum was collapsed. There was no evidence of any other underlying gastrointestinal (GI) disease. An intraluminal mass was observed approximately 30 cm proximal to the terminal ileum at the transition point of the SBO (figure 2). An enterotomy was performed in a longitudinal fashion just proximal to the intraluminal mass and a peach pit was retrieved (figure 3). The ileum was then closed in two layers in a transverse orientation. The bowel obstruction was relieved following removal of the peach pit.

Figure 2.

Intraluminal mass in the ileum (yellow arrow). Note the collapsed bowel distal to the obstruction (blue arrow).

Figure 3.

Peach pit retrieved from the distal ileum measuring 4.0×3.0 cm (A). Plain film radiograph of retrieved peach pit (B).

Outcome and follow-up

A plain film radiograph of the specimen showed a heterogeneous, ovoid, radiopaque foreign body (figure 3). When interviewed postoperatively, the patient stated that he did not recall ingesting the pit. The postoperative course was complicated by a mild wound haematoma and the patient was discharged on postoperative day 5.

Discussion

SBO due to fruit pit impaction is uncommon. Ingested pits usually pass through the GI tract without complications. However, they may occasionally cause SBO, either directly due to impaction or secondary to formation of a bezoar. The most frequent site of impaction is where the ileum is at its narrowest, approximately 50–75 cm from the ileocecal junction.¹ In addition, peristalsis at this site is diminished, further increasing the risk of obstruction. Impaction can also occur at the pylorus,² duodenum,³ colon⁴ and rectum.⁵ It is often seen in young children and in the presence of underlying GI disease, particularly colon cancer. Other predisposing factors include the presence of psychiatric illness, neurocognitive dysfunction, lack of teeth, digestive insufficiency (often due to gastrectomy), intestinal strictures, diverticulum and Crohn’s disease.^6–8

While a history of recent pit ingestion and predisposing factors should be considered when formulating a differential diagnosis, they may not be present, as in this case. Moreover, SBO due to fruit pit impaction may exhibit clinical findings similar to those of gallstone ileus. Thus, careful reviewing of imaging is paramount in reaching the correct diagnosis. Gallstone ileus is characterised by the passage of a gallstone into the bowel through a cholecystoenteric fistula, often in the setting of cholecystitis. It is usually seen in the elderly and accounts for up to a quarter of SBOs in patients older than 65 years.^{9 10} Abdominal radiographs typically demonstrate the Rigler’s triad of pneumobilia, SBO and the presence of a gallstone. Pneumobilia is present in around 89% of cases of gallstone ileus¹¹ and is absent in the setting of fruit pit impaction. Furthermore, CT imaging provides a method of differentiating between gallstones and fruit pits based on morphological appearance. Most fruit pits consist of a soft seed contained within a hard and stony endocarp. On CT, this appears as an ovoid area of hypodensity, surrounded by a thick hyperdense covering. In addition, certain fruit pits including that of the peach and apricot have a ridged surface. Calcified gallstones can also appear as a hypodense centre within a hyperdense casing; however, the casing is typically thinner and gallstones are usually spherical instead of ovoid. In contrast, pure cholesterol gallstones are hypodense.¹² Iwai et al¹³ described a case of SBO secondary to peach pit impaction in a 15-year-old boy. They reviewed 29 cases of SBO due to fruit pit impaction in Japan and found 27 of the 29 cases had pre-existing GI disease. Girvin and Gupta¹⁴ reported cases of two adults in their 70s, one with a history of schizophrenia, presenting with SBO due to fruit pit impaction. These cases suggest that while SBO due to fruit pit impaction predominantly occurs in the presence of risk factors, the possibility should not be discounted in their absence.

Learning points.

• Fruit pits are a potential cause of small bowel obstruction (SBO), particularly in the presence of underlying gastrointestinal illness and psychiatric illness. It is more common in young children than in adults.

• The radiographical and clinical findings may be mistakenly attributed to gallstone ileus.

• In the setting of SBO and in the absence of cholelithiasis and pneumobilia, an ovoid body with a hyperdense covering and a hypodense centre in the lumen of the small bowel may indicate fruit pit impaction.

• If fruit pit impaction is suspected, a careful inquiry into recent eating habits may aid in diagnosis.