[A Case of Omental Desmoid Tumor after a Small Bowel Resection for Gastrointestinal Stromal Tumor] [Article in Japanese]

Here, we report a case of omental desmoid tumor after a small bowel resection for gastrointestinal stromal tumor (GIST). A 73-year-old man underwent a partial resection of small bowel for GIST. He received adjuvant therapy with imatinib due to high risk of recurrence. After 2.5 years of treatment, a follow-up CT showed a 15mm nodule in the omentum near the splenic flexure. We considered the possibility of recurrence and imatinib failure, and laparoscopic tumor resection was performed for differential diagnosis. Immunohistochemical staining showed negative for c-kit, CD34, desmin, and S100. However, it was diagnosed as desmoid tumor because of positive b-catenin. Intra-abdominal desmoid tumor should be a differential diagnosis for a new single lesion in patients with GIST.

The current study aims to review the characteristics, management, and outcomes of patients with intra-abdominal desmoid tumor post GI resection. During the period between 2007 and 2018, after a retrospective review of patients’ clinical data, 10 patients were finally included. The study comprised 10 patients (8 males). The median age was 53.5 years (range, 35–68 years). Two patients diagnosed as familial adenomatous polyposis (FAP). All the patients underwent previous GI resection: three (30%) for colon cancer, three (30%) gastrectomy, two (20%) total proctocolectomy with ileal pouch-anal anastomosis (TPC+IPAA) for FAP, one (10%) low anterior resection (three rectal cancers) and one (10%) distal pancreatectomy. The tumor was found to be in bowel mesentery in eight cases (80%). The median tumor size was 5.3 cm (range, 2.6–19.0 cm). Six patients (60%) underwent open resection, while four patients (40%) underwent laparoscopic surgery. Complications occurred in five cases (50%) and ranged from Clavien-Dindo (II–III). The median follow-up period was 16.5 months (1.5–136.0 months) with recurrence in one case (10%). Pathology came out to be desmoid tumor fibromatosis in all cases. When a mass develops after surgical resection for abdominal GI malignancy and tends to be large in size, located in the bowel mesentery and away from previous primary tumor site, most probably it is desmoid rather than tumor recurrence.

Desmoid tumor, also called aggressive fibromatosis, is a rare fibroblastic proliferation of connective tissue and skeletal muscle aponeurosis. The aetiology of desmoid tumours is poorly understood, but they have been related with oestrogen stimuli, previous trauma, surgical interventions and pregnancy. Although it is characterized by not having potential for metastasize or differentiate, it is a non encapsulated lesion, with an infiltrative growth and unpredictable behaviour. In this way, it could have either an aggressive pattern, when compared with other low degree malignancy sarcomas, or a very indolent one, even with spontaneous regression. Therapeutic options in desmoid have been changing over these last years, as surgery upfront in asymptomatic patients has been superseded by active surveillance. However, treatment has to be individualized in some specific scenarios such as intra-abdominal lesions. We present two cases of patients diagnosed with an intra-abdominal desmoid tumour with threatening behaviour, the treatment approach and final resolution.

The aim of this study was to evaluate the benefit of using quantitative diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) mapping in the initial diagnosis and post-therapeutic follow-up of extremity soft tissue masses.This study included 90 patients with extremity soft tissue masses. The DWI was obtained with 3 b values, including 0, 400, and 800 s/mm2. Benign masses, fibromatosis, and malignant soft tissue masses had mean ADC values of 1.18 ñ 1.0191 ? 10-3 mm2/s; 1.31 ñ 0.245 ? 10-3 mm2/sec; and 1.3 ñ 0.7 ? 10-3 mm2/s, respectively. Analysis of the post-therapy follow-up studies of fibromatosis showed that lesions with favorable response to chemotherapy or radiotherapy (8/12) exhibited significantly lower ADC values than those showing progressive disease course. DWI with ADC mapping of extremity soft tissue tumors are so complicated that they alone may not be of much value in differentiating between benign and malignant tumors; however, it can be used as a tool for monitoring response to treatment.

A 36-year-old Caucasian female weighing 60?kg with Gardener’s syndrome with a history of abdominal surgery was presented to our department with progressive abdominal distention associated with paroxysmal pain. With the use of CT, the patient was diagnosed with a mass arising from the mesenterial region.The patient had normal kidney function and nonalcoholic steatohepatitis. The patient was indicated for MVTx. After 16 months on the waiting list, the patient received a multivisceral graft from a deceased donor. Following the restoration of graft vascular flow, the patient’s right kidney was removed and the DT dissected ex vivo before autotransplantation into the right pelvic fossa. The patient received immunosuppressive, antithrombotic, and antibiotic treatment. There was no acute rejection, though the patient experienced pulmonary infection, dysphagia, and oesophageal reflux with fungal infection. The patient had required temporary dialysis for acute renal failure for 75 days. One year after the surgery, nausea and violent vomiting caused delayed gastric emptying caused by spastic pylorus. Clinical improvement was achieved using gastric peroral endoscopic myotomy (G-POEM). MVTx with kidney autotransplantation is a feasible treatment option in patients with familiar adenomatous polyposis complicated by an abdominal DT. Precise tumour dissection with nephron-sparing surgery was carried ex vivo. G-POEM was used to relieve MVTx-related gastroparesis. The patient had no disease reoccurrence after one-year follow-up.

A patient in the fifth decade of life with a history of ductal carcinoma-in-situ, status post bilateral mastectomy and silicone implant placement, presented with a palpable mass in the left breast, core biopsy proven to be a desmoid tumor underneath the implant. The patient underwent two cryoablation procedures in a six-month period. During both procedures part of the implant was included in the ablation zone without any negative effects on the implant. Cryoablation is a feasible treatment option for desmoid tumors adjacent to silicone breast implants.