Description

A 70-year-old woman presented with an 8-week history of an enlarging asymmetric and tender abdominal mass and microcytic anaemia but no obvious bleeding, weight loss or change in bowel habit (figure 1). This had been investigated 4 weeks ago, and at that time she was diagnosed with a rectus sheath haematoma (RSH) secondary to previous abdominal wall strain—the main risk factor for RSH, followed by anticoagulation1 ,2— on the basis of ultrasound and subsequent CT findings, and was prescribed iron tablets at this point. However, as the mass persisted, the patient had sought further medical advice.

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Figure 1

Sagittal view of the abdominal CT scan, showing a large, well-defined, thin-walled homogeneous mass extending into the soft tissue component of the abdominal wall.

Although the original diagnosis did fit the presentation, in view of the enlarging mass, worsening anaemia and lack of risk factors for bleeding1 (the only medications were atenolol and ferrous fumarate) the patient's scans were re-reviewed by the consultant radiologist and surgeon; the patient was transfused 4 units in the interim. As concerns were raised that this could be an unusual presentation of a malignancy, an urgent colonoscopy was performed that revealed an obstructing growth in the mid-transverse colon (figure 2). The patient subsequently underwent an open right hemicolectomy and ileotransverse anastomosis for a large colonic carcinoma of the hepatic flexure, which was confirmed at histology to be a moderately differentiated T4aN0MX Dukes B adenocarcinoma invading the anterior abdominal, with rupture and fistula tract formation, thereby mimicking an RSH.

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Figure 2

Axial view of the abdominal CT, showing the mass lying adjacent to the proximal transverse colon.

Colonic cancers can occasionally invade the abdominal wall, but have rarely been documented to bleed and fistulate.3 This case highlights that the review of previous investigations in the context of the whole clinical picture is imperative for the swift diagnosis and management of this unusual presentation of bowel cancer.