Intra-abdominal Desmoid-Type Fibromatosis Mimicking Diverticulitis With Abscess: A Case Report

Desmoid-type fibromatosis in the setting of malignant peritoneal mesothelioma: a case report of two rare diseases

BACKGROUND

Desmoid-type fibromatosis (DTF) is a rare benign lesion that usually arises from the abdominal wall or extremities and rarely from the mesentery or intrabdominal organs. Malignant peritoneal mesothelioma is also a rare, yet aggressive disease. To our knowledge, this is the first case report of desmoid-type fibromatosis in the setting of malignant peritoneal mesothelioma.

CASE PRESENTATION

An early 30-year-old female was referred to our center for large intra-abdominal mass concerning for recurrent malignant peritoneal mesothelioma after previous cytoreductive surgery with hyperthermic intraperitoneal chemotherapy and adjuvant chemotherapy. Further investigation revealed a large mesenteric mass, which was resected en bloc with the cecum and terminal ileum. Pathologic findings confirmed a surprising diagnosis of desmoid-type fibromatosis.

CONCLUSIONS

No adjuvant therapy was offered to this patient due to negative tumor margins; however, close follow-up will be provided for recurrence of both malignant peritoneal mesothelioma and desmoid-type fibromatosis, which can be differentiated in the future via biopsy in this patient.

Large desmoid tumour of the small bowel mesentery

A 74-year-old man was being investigated for a pancreatic insulinoma when an incidental mesenteric mass measuring 2.6 cm x 2.5 cm was noticed on CT imaging. A wait-and-see approach was decided on. Thirty-nine months later, the patient presented with symptoms of abdominal obstruction. CT images revealed the mesenteric mass filled majority of the abdominal cavity and measured 29 cm x 26 cm x 16 cm. The patient underwent an open bypass gastrojejunostomy which stopped working a few weeks later due to further compression by the tumour. A debulking surgery was performed: a right hemicolectomy and small bowel resection with excision of the desmoid tumour and bypass gastrojejunostomy. The tumour measured 12.6 kg and was macroscopically visualised to have a white cut surface with a focal translucent area. Microscopic analysis revealed bland spindle cells with pale eosinophilic cytoplasm showing no cytological atypia, in keeping with a mesenteric desmoid tumour. Currently, two and a half years from the debulking surgery, the patient remains well and in remission with planned surveillance.

Familial adenomatous polyposis associated with desmoid tumors presenting with abdominal abscess: A case report and literature review

RATIONALE

Familial adenomatous polyposis (FAP) associated with desmoids tumors (DTs) complicated by abscess formation is rare. The management is not easy and the choice of the best treatment may be controversial.

PATIENT CONCERNS

A 33-year-old man was admitted to our hospital for abdominal pain, fever, chills, nausea, and vomiting. He had a family history of FAP, and history of abdominal surgery.

DIAGNOSES

An abdominal enhanced chest computed tomography (CT) scan revealed a soft tissue mass in the abdominal wall and an irregular mesenteric soft tissue mass with internal fistula and intra-abdominal abscess. A CT-guided biopsy of the abdominal wall mass revealed DTs.

INTERVENTIONS

The patient was given oral antibiotics for 6 months, and ultimately underwent surgery.

OUTCOMES

The patient had no evidence of recurrence on follow-up at 10 months.

LESSONS

This case indicates that for patients with FAP who have a history of abdominal surgery and a progressively enlarging mass and abscess in the abdomen, it is necessary to consider the possibility of DTs. FAP-related DTs are rarely complicated by abscess formation. Antibiotic therapy plus surgical resection of the tumor may be effective and make good prognosis.