Desmoid tumors are benign proliferations of spindle cells originating in fibro-aponeurotic tissue. They often occur in the abdominal wall, mesentery, and retroperitoneum, and may cause various symptoms such as gastrointestinal tract obstruction, perforation, abscesses, and ureteral obstruction. No consensus has been reached concerning the treatment of desmoid tumors in familial adenomatous polyposis (FAP) patients. Pharmacotherapy, surgery, and conservative treatment (follow-up) may be selected according to the site and severity of the tumors (1). Many patients with FAP die from desmoid tumors, which can arise spontaneously but often appear to be surgically induced by prophylactic colectomy. The overall prevalence of desmoid disease is 15% of 379 patients with APC germline mutation (2). Ishida et al reported that desmoid tumors accounted for about 10% (n=71) of deaths due to FAP between 1990 and 2003, approximately 3.0% (n=268) up to 1980, and approximately 4.8% (n=171) between 1981 and 1990(1). They are the second most common cause of death in patients with FAP following colorectal cancers, and their incidence is increasing (1,3). Although many patients can live a long life with desmoid tumors without symptoms, when symptoms appear (ranging from bowel or ureteric obstruction to bowel perforation with abscess and fistula) or when there is a risk of functional impairment, a wide spectrum of therapies (local and systemic) can be useful in improving symptoms and controlling the disease (4-6). However, the tumors are often refractory and are reported to recur in about 70% of patients following resection (4). Chemotherapy, surgery, and radiation therapy have been reported as treatments for desmoid tumors, but no consensus on the best treatment has been reached. Surgical treatment is often required for large tumors (6-9). Church et al retrospectively analyzed the treatment strategies actually performed and suggested a staging system for desmoid tumors. In this system, all stage-IV cases required some type of treatment, such as surgery, chemotherapy, or radiation (10). There is one report that palliative surgery was effective for a large symptomatic desmoid tumor (11).

The aim of this case study was to present our experience of resecting a giant mesenteric desmoid tumor in stage IV, resulting in a good postoperative course and improvement of quality of life and prognosis of the patient.

A 41-year-old half-Japanese half-Caucasian male who had been diagnosed with intra-abdominal desmoid tumors associated with FAP at age 13 visited our hospital with fever, abdominal pain, vomiting, and oral uptake disorder. His Caucasian father died from FAP. An abdominal mass was detected at the age of 35, but the patient was diagnosed as not eligible for surgery. He had been treated with abdominal wall incision for decompression and chemotherapy (tamoxifen, imatinib, doxorubicin, and dacarbazine) since he was 38 years of age. The tumors exposed on the abdominal wall were treated using Mohs paste for more than one year. The therapeutic response was progressive disease, based on Modified Response Evaluation Criteria in Solid Tumors (mRECIST). There was no history of prophylactic colectomy.

A desmoid tumor was exposed on the body surface and the tumor invaded the abdominal wall and small intestine; thus, pus and digestive juice from the tumor were observed (Fig. 1). A blood test showed a mild increase in neutrophilia (15,300/µl) and C-reactive protein (CRP) (8.47 mg/dl). Serum albumin was 2.7 g/dl. Enhanced computed tomography (CT) examination revealed a large tumor throughout the abdominal cavity. A branch of the superior mesenteric artery (SMA) penetrated the tumor. An abscess was also found in the upper abdomen (Fig. 2).

Although it was unlikely that the tumor could be completely removed by surgery, and the risk of postoperative complications (short bowel syndrome, massive bleeding) was high, the medical team decided to perform surgery for the purpose of symptom improvement.

Desmoid tumors are benign monoclonal fibroblastic proliferations arising in musculoaponeurotic structures. They often cause various symptoms such as gastrointestinal tract obstruction, perforation, abscesses, and ureteral obstruction. There are currently no national or international guidelines for the management of desmoid tumors. The strategy of therapy which may be selected consists of surgery, pharmacotherapy or conservative treatment (follow-up). In some cases, the mass is considered unresectable and pharmacotherapy is selected (12).

In conclusion, in this case, the desmoid tumor prevented oral intake of food by the patient. To improve his symptoms, we performed a palliative operation which required some contrivances such as a balloon catheter in the SMA to avoid bleeding and reconstruction of the abdominal wall. Despite massive resection of the desmoid tumor and the small intestine, the patient was able to maintain his nutritional status by oral intake alone without tube feeding. His quality of life improved for the 20 months following the operation until an intestinal obstruction occurred 2 months prior to his death.