Rare hepatic malignant tumors: dynamic CT, MRI, and clinicopathologic features: with analysis of 54 cases and review of the literature.

Aim: To evaluate the dynamic CT, MRI, and clinicopathologic characteristics of rare hepatic malignant tumors (HRMTs), improving the understanding and diagnosis of the tumors.

Methods: A retrospective analysis of 54 cases of HRMTs diagnosed by pathology in our hospital during January 1, 2005 to September 1, 2011.

Results: The types of tumors included hepatic sarcoma (n = 8), malignant lymphoma (n = 4), malignant fibrous histiocytoma (MFH, n = 7), malignant melanoma (MM, n = 4), squamous cell carcinoma (SCC, n = 5), primary clear cell carcinoma of the liver (PCCCL, n = 7), stromal tumors (ST n = 4), hepatoblastoma (HB, n = 8), carcinoid (n = 6), primary primitive neuroectodermal tumor (pPNET, n = 1). Age of the patients ranged from 1 to 79 years (mean = 46.7 years). There were more men in this group (34/54). Symptoms of HRMTs show no specificity. Except PCCCL and HB, the serum AFP of most HRMTs was negative. 43 patients had a single hepatic mass, and 11 patients had multiple hepatic masses. Diameters ranged from 2 to 15 cm (mean = 7.7 cm). Precontrast CT revealed that most masses had uneven density (n = 46) and ill-demarcated margin (n = 37). Enhanced CT showed most lesions unevenly enhanced (n = 49), of which PCCCL had a prompt enhancement in the arterial phase and rapid wash-out on the portal venous phase and delayed phase; malignant lymphoma and ST had slight enhancement, MFH and undifferentiated embryonal sarcoma had gradual delayed enhancement. Most masses had low-signal on T1WI and high-signal on T2WI, while MM had high-signal on T1WI and low-signal on T2WI.

Conclusions: Although there is frequent overlap in the CT, MRI, and clinicopathologic appearances between the rare malignant tumors, some HRMTs have characteristic imaging features that can suggest a specific diagnosis.