Development of multifocal extra-abdominal desmoid fibromatosis after surgical resection

Multifocal Desmoid-Type Fibromatosis: Case Series and Potential Relationship to Neuronal Spread

Multifocal desmoid-type fibromatosis (DTF) is very rare and usually regional. We report three cases that initially appeared to be multifocal, but subsequent detailed imaging revealed unsuspected tracking along nerves in two cases. This neural spread is reminiscent of neuromuscular choristoma (NMC), a rare developmental lesion in which mature skeletal muscle cells, or rarely smooth muscle cells, infiltrate and enlarge peripheral nerves. NMC is frequently associated with DTF. These two cases suggest that DTF spread along nerves and appeared as distinct multifocal lesions while actually being contiguous. The third case was felt to represent true multifocal tumor development, possibly due to tumor seeding at the time of chest surgery. The relationship of DTF to NMC is discussed.

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

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.

Sporadic desmoid fibromatosis of the neck after dorsal spondylodesis of the cervical spine

Background:

Rare soft-tissue tumors, termed desmoid fibromatosis (DF), are comprised proliferated spindle cell fibroblasts and myofibroblasts embedded in a prominent collagenous stroma. They can occur either sporadically, due to prior trauma or surgery, or may have a genetic component. Clinically, DF has a high infiltrative growth/ local recurrence rate, but does not metastasize.

Case Description:

A 58-year-old male underwent a C5-C7 laminectomy/instrumented fusion. Two years later, he presented with a large gross swelling on the right side of the neck. The lesion was removed and proved to histologically consist of DF. Within the first postoperative 12 months, tumor did not recur.

Conclusion:

Sporadic DF may follow trauma or prior surgery. Symptomatic tumors are treated by surgical en bloc resection (preferably R0). If lesions are inoperable, partially resected, or recur, different hormonal/ chemotherapeutic systematic treatment options are available (e.g., tamoxifen or tyrosine kinase inhibitors). In the future, better molecular understanding of DF likely offers additional therapeutic approaches (e.g., immune checkpoint inhibitors).