A case of invasive abdominal wall fibromatosis presenting as intra-abdominal mass

Summary

A 26-year-old lady presented with a palpable mass of one and half year's duration, on the left side of her abdomen. It was painless but mild dragging sense was present. She had no history of fever, vomiting or any other complaint. She noticed the mass for the first time during her second trimester of third pregnancy. She had no history of previous surgery. Her bladder and bowel habits were normal. On general examination, patient was afebrile, vitals were stable. Mild pallor was present. Abdominal examination revealed a fairly globular non-tender mass measuring 20 cms across, occupying left flank and umbilicus. It was soft to firm in consistency and immobile. FNAC reported as benign spindle cell tumour. A contrast-enhanced computed tomography (CT) scan revealed a large heterogeneously enhancing well defined soft tissue intra-abdominal mass in left flank and left retroperitoneum with invasion of left flank muscles suggestive of benign soft tissue tumour with minimal ascites. At exploratory laparotomy, a mass of around 30 cm x 25 cm was present extending from anterolateral abdominal wall into the retroperitoneum with multiple feeding vessels present, without any solid organ adherence. The mass was excised completely. Gross examination of the cut section reveals firm whorled mass located within surrounded by skeletal muscle. Histopathological examination revealed an intrabdominal fibromatosis with densely collagenised stroma and dilated vessels with myxoid change. Microscopic picture of the tissue showed fish in a stream pattern and stellate cells. There were no intraoperative or postoperative complications. Patient was discharged on 8th postoperative day. Follow up till 2 years bears no evidence of recurrence.