Sex: female
Age: 44 years
History
In 1993 abdomino-perineal resection of the rectum had been performed due to a colo-rectal carcinoma (Dukes B). 2 years later a single metastasis had been excised from the deep central portion of the right liver-lobe.
Laboratory data
CEA 53 ng/ml
Physical findings
Normal.
Case text
The patient was referred to the hospital due to continuously increasing CEA-values. There was no other evidence of tumor recurrence. Sonography revealed some irregularities of the surface of the right liver lobe which was presumed to be a normal aspect following tumor excision.
Image 1-3
CT of the liver, contrast-enhanced.
Dual-phase spiral-CT, axial section at the central portion of the liver; collimation: 5mm; table feed 10mm.
Image 1: Unenhanced CT scan.
Images 2 and 3: Contrast enhanced CT scans, portal venous phase.
Image 4-6
MRI of the liver contrast enhanced.
Image 4: Axial T2-weighted TSE image (TR/TE 3200/138ms, 5mm slice thickness).
Image 5: Axial T1-weighted FLASH image (TR/TE 170/4,4ms; ( = 80°), 5mm slice thickness, precontrast).
Image 6: T1-weighted FLASH image (TR/TE 170/4,4ms; ( = 80°), 5mm slice thickness, after iv-injection of contrast.
Image 1-3
1. What is the abnormality present on the pre- contrast scan?
CT shows a blurred low-attenuation area in the right liver lobe, no space-occupying aspect.
2. What is the aspect of this lesion following intravenous contrast injection?
The lesion now appears slightly hypodense with the region of surgical incision being wedge-shaped and well demarcated. In addition an ill defined intraparenchymal lesion is noted close to the right branch of the portal vein.
3. What is your diagnosis?
Centrally located recurrence of tumor metastasis.
4. What is the differential diagnosis?
Postoperative scar.
5. What is the next diagnostic step?
MRI of the liver.
Image 4-6
6. What is the abnormality present on the unenhanced T1- and T2 weighted MR images of the liver?
The T2-weighted image shows an ill-defined lesion in the deep central portion of the right liver lobe. The mass appears slightly hyperintense compared to the normal parenchyma.
There is a second small hyperintens lesion within the posterolateral liver capsule indicating the postoperative cleft. The central lesion is well depicted on the T1-weighted image appearing as lobulated hypointense mass, which spreads to the right branch of the portal vein.
7. Does MRI after administration of the hepato-biliary contrast agent TESLASCAN®/ MnDPDP ( mangafodipir) -Nycomed Amersham provide any additional information?
Due to the enhanced "signal/noise" ratio the delineation of the peripheral lesion as well as the central space occupying mass is clearly facilitated. There is no uptake of MnDPDP within both lesions suggesting the central one to be malignant due to its size and shape.
8. What is your diagnosis?
Tumor recurrence in the right liver lobe with close relationship to the right branch of the portal-vein.
Final diagnosis
Tumor recurrence in the right liver lobe with close relationship to the right branch of the portal-vein.
Differential diagnosis
A primary malignancy, although less likely, has to be considered.
Due to the vascular and myxoid tissue a fibrous scar of the liver-parenchyma often appears hyperintense on T2-weighted and hypointense on T1-weighted images, so in many cases it may not be reliably differentiated from tumor recurrence solely on the base of its signal intensity.
Discussion
Right hemihepatectomy was performed in this patient showing the centrally located metastasis of colo-rectal carcinoma. Three weeks later, the CEA-value was within the normal range.
An elevated CEA-value may be the only indicator of tumor recurrence or metastatic progress in case of colo-rectal carcinoma. Following liver-surgery, the differentiation of postoperative changes of the liver-parenchyma from tumor- regrowth may be a challenge as long as the size of a lesion is limited. Due to the vascular and myxoid tissue a fibrous scar of the liver-parenchyma often appears hyperintense on T2- and hypointense on T1-weighted images. So in many cases it may not be reliably differentiated from tumor recurrence solely on the base of its signal intensity. This illustrates the demand for thorough analysis of the shape of a lesion, in particular, if percutaneous biopsy is intended. In this case, the nodular aspect of the tumor was well depicted on the T1-weighted images after injection of TESLASCAN®/ MnDPDP (mangafodipir) (Nycomed Amersham).