Teaching Case

A 65 year-old female. Previous surgery for colon carcinoma.

The patient undergoes abdominal US one year after resection of left colon carcinoma. US shows a solid 29x27mm nodule in the caudate lobe, slightly hyperechoic with regular margins. Laboratory tests show increased levels of tumour markers (CEA and CA19.9). MRI of the liver is performed with axial T2-weighted sequences and with T1-weighted fat suppressed sequences, before and after Gadolium injection. On MR, the nodule consists of multiple small fluid-filled cystic spaces divided by thin septa. After gadolinium injection there is slight enhancement of the cystic wall and of some of the septa. There is no evidence of other liver lesion. The MR appearance suggests a possible diagnosis of lymphangioma. After two months, due to further addition in serum tumour markers levels and increase in size at US, percutaneous biopsy is performed. The cytologist’s diagnosis is metastasis from mucoid adenocarcinoma. The patient undergoes segmental liver resection and the lesion is confirmed at pathology.

Liver metastases are usually solid. Cystic metastases are rare and are mainly described in ovarian carcinoma, melanoma, leiomyosarcoma, mucinous colo-rectal carcinoma, carcinoid, cervical and lung cancer. Features that may indicate the malignant nature of "cystic" liver lesions on MRI are: a thick and irregular wall with enhancement, the presence of nodules or vegetations on the wall, a fluid-fluid level due to the presence of mucin or hemorrage. Some metastases may become cystic after chemotherapy. Cystic metastases mainly consist of a single cavity and are more rarely multiloculated. In our case the lesion consisted of multiple cavities of 2-3 mm in size, separated by thin septations. A diagnosis of secondary malignancy was made only by percutaneous biopsy which was undertaken because of "cyst" growth and increase in CEA and CA19.9 levels.