(P 264) DESMOID AND TRAUMA: REAL INCIDENCE AND MEDICOLEGAL ASPECTS OF CAUSALITY

Objective: The development of desmoid tumors (DT) is often reported to be associated with local trauma, and this was first almost a century ago. After surgical procedures, a DT developing in the operation field is easy to classify as the initiation event. The etio-pathogenic responsibility of the initial trauma is not only important from a medical point of view, it is also of obvious interest for medicolegal aspects when patients are involved in court procedures.
We reviewed our database to look for the proportion of patients with documented traumatic injuries and subsequent DT. We also classified the type of trauma (surgical, blunt/fracture, implants) and looked for the distribution of known mutations of the beta-catenin gene between traumatic and non-traumatic DTs.

Methods: We analyzed a prospectively kept database, in which we had documented patient data since 1/2005. Until 12/2021 we have treated and/or consulted 572 patients with the histologically confirmed diagnosis of a desmoid tumor. There were 392 women (68,6 %) and 179 males (31,4%), median age at disease onset 37,7 yrs (f) and 39,3 (m) yrs. Of these patients, we excluded 14 pts. in whom the diagnosis had to be changed at reference pathology (nodular fasciitis, endometriosis, DDLS, others). 29 pts with Gardner syndrome, and 84 females with typical post-pregnancy desmoids of the rectus abdominis muscle were also excluded because they did seem not belong to the trauma group or had genetic reason for desmoid development, see figure 1.

Results: Of the 445 patients remaining, 118 pts remembered trauma and this could be verified by clinical data (26.5%). 224 patients did not remember a trauma, and in 103 patients the data were inconclusive. If this latter group is excluded, the proportion of DT-trauma rises to 34.5%. Of the 118 pts, a blunt trauma (car, fracture) reported 27 pts (22.9%), another 68 pts (57.6%) reported an iatrogenic/surgical trauma, 14 pts (11.8%) had a DT at the site of punctual trauma (injection, trocar), 9 pts (7.6%) had a DT the site of an artificial implant (f.e. hernia repair). Median lag time between trauma and DT detection was 23 months (5-76 months), ns.
The overall distribution of T41A mutations to S45F/P was 55.9% : 27.4%, (wt 16,6%), whereas in trauma-associated the distribution was similar T41A : S45F/P = 58.4% vs 18.8%, (wt 22,6%). In total, 11 patients had required medico-legal support at court procedures, six of them to fight for recognition of the trauma as the major factor for DT development.

Conclusion: There is a significant subgroup of at least one fourth of DT patients with a documented trauma-associated tumor development, median 2 years after trauma. DT at the surgical site is the predominant location, but other sites as implants must not be forgotten. To confirm the traumatic origin of DT is important for around 10% of those patients during court procedures. We found no data to support that trauma-associated DT have different molecular feature at the beta-catenin mutational status level.