A rare sporadic pancreatic desmoid fibromatosis with splenic vein invasion diagnosed by CT scan-guided core needle biopsy: a case report with possible differential diagnosis from metastatic colorectal or renal cancer

Desmoid tumor is a rare fibroblastic proliferation with a variable and often unpredictable clinical course that arises in the deep soft tissues and is characterized by infiltrative growth with tendency to local recurrence but not to metastasize. A 49-year-old man was referred for a second opinion regarding a pancreatic mass. With a personal neoplastic background of two different tumors, we considered as a high probability of being metastatic of his previous colorectal or renal cancers, in a peritoneal implant. Due to the unclear origin and nature of the mass, we opted for requesting a computed tomography (CT)-guided core needle biopsy that could eventually lead to a surgical and/or chemotherapy treatment. So far, this is the first case of pancreatic desmoid fibromatosis with splenic vein invasion diagnosed by CT scan-guided core needle biopsy. Surgery should be performed by an experienced surgeon as first-line therapy, provided expected surgical morbidity is limited.

Background: Desmoid fibromatosis (DF) is a rare and locally infiltrative monoclonal fibroblastic proliferation arising from connective tissues, with lack of metastatic potential. About 10% of all DF cases are intra-abdominally sited. Complications in this site, due to the locally infiltrative nature of the disease, may be severe and potentially life threatening. However, data on incidence, management, and outcome of these complications are limited. Aim: Data of patients with sporadic or FAP-related intra-abdominal DF treated at Istituto Nazionale dei Tumori (INT) in Milano from 2005 to 2020 who developed a serious complication during the course of their disease were retrospectively collected and analyzed with a descriptive statistics. Methods and results: Out of 72 intra-abdominal DF, 8 cases were identified (M/F: 5/3, median age: 35 years, FAP-related/sporadic: 2/6): 3 with bowel obstruction, 5 with bowel perforation. In 4 cases the serious complication was the first evidence of disease; in the other 4 cases it occurred at a time interval from diagnosis in the range of 4-44 months (during an active surveillance program in one case and during chemotherapy in the other 3 cases). A surgical treatment was feasible and successful in 5 cases. In 3 surgically unmanageable patients, all progressing and experiencing acute complications while on chemotherapy, a non-surgical approach with intensive supportive treatment and with a prompt change of chemotherapy regimen was implemented, being successful in two, the other patient dying due to a concomitant progressive lymphoma thereafter. Conclusion: In this series of intra-abdominal DF, the incidence of serious complications was 11%. Most patients were successfully treated with surgery. When surgery was deemed to be unfeasible, a conservative management with intensive supportive care and a careful choice of chemotherapy was adopted, ensuring a favorable outcome in most.

Desmoid tumour of the colon is a very rare and aggressive type of intra-abdominal desmoid fibromatosis. Patients can present with a range of symptoms from a mild chronic abdominal pain to those of an acute abdomen. We present a rare case of abdominal fibromatosis that presented as a rapidly growing mass with free intraperitoneal gas. Intraoperatively however, we found a large tumour arising from the wall of the transverse colon and local necrosis. No bowel perforation was noted. The tumour was removed with a wide resection of transverse colon’s wall instead of colectomy. The histopathology reported benign fibromatosis and excluded malignancy.

Background: We aimed to investigate changes in volume and MRI T2-weighted intensity in desmoid-type fibromatosis (DF) receiving methotrexate plus vinca-alkaloids (MTX-VA) at Istituto Nazionale dei Tumori, Milan. Methods: All cases of sporadic DF treated with MTX-VA from 1999 to 2019 were reviewed. MRIs at baseline, 6 and 12 months of chemotherapy and at treatment withdrawal were retrospectively reviewed, contouring the tumor lesion and measuring diameters, volume, and mean T2-signal intensity (normalized to muscle) changes. These parameters were also evaluated according to clinical variables. Results: Thirty-two DF patients were identified. Best RECIST response was: 25% partial response, 69% stable disease, 6% progression. A ?65% tumor volume reduction was observed in 38%, <65% reduction in 53%, an increase in 9%. 22% had RECIST stable disease with a ?65% tumor volume reduction. T2-signal intensity decreased by ?50% in 47%, <50% in 41% and increased in 12%. In patients with symptomatic improvement while on therapy and in patients maintaining symptomatic improvement during follow-up, median T2-signal intensity showed a reduction along the time points (3.0, 1.9, 1.2, 1.1; 2.9, 2.0, 1.2, 1.2, respectively); in patients without symptomatic improvement and in those clinically progressing during follow-up, a reduction was not observed. High T2-signal intensity at baseline was observed in patients showing RECIST progression during follow-up. Conclusions: In this series, RECIST detected a lower proportion of responses as compared to volumetric and T2-signal changes. T2-signal reduction seemed to better reflect symptomatic improvement. High T2-signal intensity at baseline was related to a higher proportion of further progression.