UCLA

BACKGROUND Distinguishing between primary and metastatic malignancy can be challenging despite advances in diagnostic imaging, tissue sampling techniques, and immunohistochemistry. CASE REPORT Herein, we describe 2 cases of obscure liver lesions which were ultimately determined to be malignant and from metastatic disease. In both cases, the liver metastases were uniquely "homomorphic," i.e., radiographically resembling the primary tumor source (in the first case a dilated tubular appearance akin to the hepatopancreatic ampulla and in the second case a haustrated bowel appearance akin to the colon). CONCLUSIONS These cases illustrate the recently reported concept of tumor homomorphism as a potential diagnostic pearl to facilitate timely diagnosis of malignant-appearing liver lesions of obscure etiology and source and thereby guide management accordingly.