Intraabdominal sporadic desmoid tumors and inflammation: an updated literature review and presentation and insights on pathogenesis of synchronous sporadic mesenteric desmoid tumors occurring after surgery for necrotizing pancreatitis

Abstract

Sporadic intra-abdominal desmoid tumors are rare and known to potentially occur after trauma including previous surgery, although knowledge of the underlying pathogenetic mechanism is still limited. We reviewed the recent literature on sporadic intraabdominal desmoids and inflammation as we investigated the mutational and epigenetic makeup of a case of multiple synchronous mesenterial desmoids occurring after necrotizing pancreatitis. A 62-year-old man had four mesenteric masses up to 4.8 cm diameter detected on CT eighteen months after laparotomy for peripancreatic collections from necrotizing pancreatitis. All tumors were excised and diagnosed as mesenteric desmoids. DNA from peripheral blood was tested for a multigene panel. The tumour DNA was screened for three most frequent β-catenin gene mutations T41A, S45F and S45P. Expression levels of miR-21-3p and miR-197-3-p were compared between the desmoid tumors and other wild-type sporadic desmoids. The T41A CTNNB1 mutation was present in all four desmoid tumors. miR-21-3p and miR-197-3p were respectively upregulated and down-regulated in the mutated sporadic mesenteric desmoids, with respect to wild-type lesions. The patient is free from recurrence 34 months post-surgery. The literature review did not show similar studies. To our knowledge, this is the first study to interrogate genetic and epigenetic signature of multiple intraabdominal desmoids to investigate potential association with abdominal inflammation following surgery for necrotizing pancreatitis. We found mutational and epigenetic features that hint at potential activation of inflammation pathways within the desmoid tumor.

Keywords: Beta catenin; Desmoid tumor; Inflammation; Mutation; Pancreatitis; microRNA.

Fig. 1

Laparotomy for necrotizing pancreatitis eighteen months before admission for desmoid tumors; pancreatic necrosis eroding into the transverse mesocolon (a), partly walled off by the mesentery (b) of the first jejunal loop (c)

Fig. 2

Contrast CT scan eighteen months after laparotomy for walled off pancreatic necrosis, showing four discrete intraabdominal masses (arrows), ranging from 1.6 to 4.8 cm diameter, isoattenuating to hyperattenuating to muscle

Fig. 3

One of the three mesenteric masses resected at first surgical approach, lifted up and showing no cleavage from the small bowel. Working diagnosis included GIST

Fig. 4

Pathology of the three desmoid tumors resected: a Spindle cell proliferation arranged in long fascicle; b nuclear positivity for beta-catenin; c assive infiltration of ileal wall

Fig. 5

Coronal scan of contrast CT three months after resection of three intraabdominal sporadic desmoids: the patient was symptomatic for abdominal pain; the fourth lesion, located at the mesentery of the first jejunal loop, had increased in volume with respect to previous control, and there were signs of vascular and bowel compression

Fig. 6

Intraoperative a aspect of the fourth desmoid tumor and specimen of in bloc resection with the first jejunal loop