Metastatic nodules of the abdominal wall: US and CT evaluation

Metastatic recurrence in the abdominal wall surgical scar is not uncommon. Our aim was to evaluate the role of ultrasonography (US), computed tomography (CT) and percutaneous fine needle aspiration biopsy in the diagnosis of metastatic recurrence along the surgical scar.

We evaluated 17 nodules in the surgical scar, either single (n=9 patients) or multiple (n=2 patients), in 11 patients operated on for known abdominal neoplasm confirmed by histology. The most common primary tumour was colonic carcinoma. All patients had undergone open surgery, and the lesions were detected at routine follow-up or at diagnostic examinations performed for clinical suspicion of recurrence. Ultrasonography (7.5-10/10-13 MHz) and fine needle biopsy were performed in all cases; contrast-enhanced CT was carried out in 10 patients. All lesions underwent histopathological examination.

The histological findings showed 16/17 metastatic nodules and one suture granuloma. Lesions had variable size (15-55 mm), roundish shape, ill-defined margins (60% cases) and hypoechoic solid echotexture. All were characterised by marked contrast medium uptake on CT examination. US-guided aspiration biopsy precisely defined the metastatic nature of the nodules in 16/17 cases. In the patient with suture granuloma, both CT and US findings suggested malignancy; however, cytology showed only scant fibrous material. The anterior abdominal wall was the most common site of metastatic disease (14 lesions).

US enables an accurate detection and diagnosis of metastatic nodules along the surgical scar. Fine needle aspiration biopsy represents, in our opinion, the most suitable procedure for providing an accurate diagnosis of this condition.