Chemotherapy-treated liver metastases mimicking hemangiomas on MR images

Background: To report the observation that chemotherapy-treated liver metas tases may mimic the appearance of hemangiomas on T2-weighted and serial pos tgadolinium gradient-echo magnetic resonance (MR) images. Methods: T2-weighted and serial postgadolinium spoiled gradient-echo images were prospectively and retrospectively analyzed in six patients. All patie nts had been treated with chemotherapy for a duration of 2-12 months. Histo pathologic evaluation of liver lesions was performed in three patients. Results: Twelve lesions that resembled hemangiomas were identified. Lesions were 0.8-5.5 cm in diameter. All were well defined, oval or lobulated, and demonstrated decreased signal intensity on T1-weighted images and increase d signal intensity on T2-weighted images. On immediate postgadolinium image s, all lesions demonstrated peripheral nodular enhancement, which coalesced on delayed imaging. Final histopathologic diagnoses were as follows: hepat ic metastases from colon cancer (two patients), ovarian cancer (two patient s), pancreatic islet cell tumor (one patient), and breast cancer (one patie nt). Conclusions: Metastases treated by chemotherapy may mimic the appearance of hemangiomas on a variety of commonly employed MR techniques. In patients u ndergoing MR imaging for the evaluation of liver metastases, a history of p rior chemotherapy administration and duration should be sought to prevent i naccurate staging and inappropriate therapeutic decision making.