Intussusception of small intestine as complication of Peutz-Jeghers syndrome with surgical correlation

Clinical History

The patient presented to the emergency department complaining of abdominal pain of acute onset. Clinical examination revealed the presence of a brown macule on the lips. His past medical history included surgery for intussusception caused by a lymph node. Family history included multiple polyps in his father and brother.

Imaging Findings

US was initially performed to evaluate the boy’s abdomen. This examination revealed the presence of a sausage-shaped mass of heterogeneous echogenicity in the left upper abdominal quadrant. On transverse images, the mass was characterized by concentric layers and a hyperechoic and hypoechoic central area. (Fig.1) This image was consistent with intussusception of the small intestine measuring 7 cm in length. A gallbladder with Phrygian cap deformity, enlarged mesenteric lymph nodes and testicular microlithiasis were also found. (Fig. 2) CT was then requested to further evaluation. The mass was located in the anatomic region of jejunum and appeared with concentric layers of high and low attenuation, representing the intussusceptum, intussuscipens and the invaginated mesenteric fat of the intussusception. This examination also confirmed the presence of enlarged mesenteric lymph nodes. (Fig. 3) Laparotomy confirmed the presence of small bowel intussusception, which was reduced. Enterotomy was carried out and revealed a polyp, which was resected. (Fig. 4)

Discussion

Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant disease caused by a mutated STK 11 gene, which is defined by the presence of benign hamartomatous polyps anywhere in the alimentary tract and characteristic dark brown macules on the lips and oral cavity. Its reported prevalence ranges from 1:25000 to 1:280000 [1-4]. PJS increases the risk for breast, genital, pancreatic cancer and mainly gastrointestinal adenocarcinoma regardless of the benign nature of the polyps [1, 3]. The risk for complications and malignancy rationalizes early treatment and surveillance protocols using either endoscopic techniques or imaging with MDCT or MR enterography. Polyps in patients with PJS also affect extradigestive positions like the renal pelvis or the nostrils [1]. Surveillance is also recommended for extragastrointestinal organs like breast and reproductive organs [5].
PJS equally affects men and women with symptomatology of small bowel intussusception, obstruction and bleeding. Intussusception and intestinal obstruction in PJS usually affect patients younger than 18 years of age and require urgent laparotomy if not spontaneously resolved [1, 2, 6]. It is well known that intussusception is mostly caused by polyps larger than 15 mm. Thus, such polyps should be removed once detected [1]. The diagnosis of PJS relies on the combination of at least two of the following criteria: small bowel hamartomatous polyps, mucocutaneous pigmentation and family history [2].
Ultrasound can identify intussusception in patients with PJS as a heterogeneous mass with hyperechoic material corresponding to the mesenteric fat and hypoechoic parts representing the oedematous bowel wall. This structure has been characterized as a “pseudokidney” [3]. MDCT enterography or enteroclysis can be used to detect polyps as multiple regular sessile or pedunculated masses of variable size with 92.8% sensitivity of and 99.2% specificity [1]. The polyps are most frequently located in the jejunum and ileum and never in the oesophagus [4]. Intussusception is easily diagnosed with standard MDCT based on the bowel-within-bowel pattern it creates. The latter may be less evident and appear as an amorphous mass depending on the bowel wall oedema and the quantity of invaginated low-attenuation mesenteric fat. Enhancing vessels can be seen within the latter. When seen on short-axis planes, intussusception appears as a target-like lesion whereas when seen on long-axis images, it is sausage-shaped. The lead mass causing the intussusception is not always identifiable [1, 4]. MR enterography and enteroclysis can be used to detect small bowel polyps as small as 3 mm in size. The use of contrast-enhanced sequences increases the number of polyps detected [1].

Differential Diagnosis List

Final Diagnosis

Surgically proven intussusception caused by a Peutz-Jeghers Syndrome hamartomatous polyp.

URL:	https://www.eurorad.org/case/12829
DOI:	10.1594/EURORAD/CASE.12829
ISSN:	1563-4086