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Neuroradiology Case of the Week

Case 69

Ravinder Sidhu MD, Ramon de Guzman MD,
and P-L Westesson MD, PhD, DDS

Clinical Presentation: A 49-year-old female with a history of breast and thyroid malignancy presented with mental status changes.

Radiological Findings:  Non-contrast enhanced head CT revealed a well-defined, 4x3x3 cm lesion with thick hyperdense rim and hyperdense fluid level within the lesion seen in right parietal lobe. There was perilesional edema compressing the right lateral ventricle (Fig. 1A). Follow up non-contrast enhanced CT done a week later showed a hyperdense nodule within the lesion (Fig. 1B). Contrast enhanced head CT showed a thick, nodular enhancement of the peripheral rim with a hyperdense nodule within the lesion (Fig. 2).

Diagnosis: Hemorrhagic metastases

Discussion:  Hemorrhage into malignant neoplasms accounts for approximately 10% of all spontaneous intracranial hematomas [1]. Significant hemorrhage is said to occur in 3-14% of brain metastases and 1-3% of gliomas [2,3]. Intracerebral metastases most prone to hemorrhage include malignant melanoma, choriocarcinoma, renal cell carcinoma, bronchogenic carcinoma, and thyroid malignancy [4]. Rare sites such as colorectal malignancy, and malignant fibrous histiocytoma have also been reported. Of the primary gliomas, glioblastoma multiforme, oligodendroglioma, and ependymoma are most likely to demonstrate hemorrhage [5, 6].
    The pathogenesis of hemorrhage into intracerebral neoplasms is multifactorial such as high grade of malignancy, extensive and abnormally formed tumor vascularity, rapid growth with subsequent necrosis, and vascular invasion have all been proposed as bleeding mechanisms [7].
    Patterns of intratumoral hemorrhage on CT scan are varied and it is often impossible on CT to distinguish hemorrhagic neoplasm from other causes of intracranial hemorrhage. Takahashi et al. classified hemorrhagic brain metastases into four patterns on CT: marginal hemorrhage; marginal hemorrhage with scattered central hemorrhage; diffuse hematoma in the tumor; cystic tumor with fluid hemorrhage forming fluid level; and extratumoral hematoma [8]. Neoplastic hemorrhage usually is more complex and heterogeneous and has a delayed hemorrhagic evolution. Delayed evolution of hematoma is thought to be due to hypoxia in masses. Hemorrhagic metastases need to be differentiated from cerebrovascular event such as hemorrhagic infarct, or ruptured arteriovenous malformation. Factors such as atypical location, multiple hemorrhagic sites, and early enhancement may suggest malignancy as the underlying cause of intracranial hemorrhage [9].
    Cerebral abscesses appear as ring enhancing lesions, however, they usually have smooth thin-walled ring as compared to thick nodular ring in metastases. Non-contrast enhanced CT scan is valuable for detecting hemorrhage. Contrast enhanced CT scan depicts the variable pattern of enhancement of vascular metastases. Hemorrhagic metastases may appear as high-signal intensity on T1-weighted MR images and high or low-signal intensity signal on T2-weighted MR images. However, marked heterogeneity, often with identifiable nonhemorrhagic tissue corresponding to tumor; diminished, irregular, or absent hemosiderin deposition, delayed hematoma evolution, blood degrading products of different ages with fluid level and pronounced or persistent edema is common in hemorrhagic metastases [10].

References:

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7. Zimmerman RA, Bilaniuk LT. Computed tomography of acute intratumoral hemorrhage. Radiology 1980; 135:355-359.
8. Takahashi M, Takekawa S, Suzuki K et al. Hemorrhagic brain metastases: analysis of computed tomography, predisposing factors and prognosis (In Japanese). Nippon Igaku Hoshasen Gakkai Zasshi 1986; 46:458-468.
9. Osborn A. Intracranial hemorrhage. Diagnostic Radiology. St. Louis; Mosby, 1994, pp187.
10. Atlas SW, Grossman RI, Gomori JM, Hackney DB, Goldberg HI, Zimmerman RA, Bilaniuk LT. Hemorrhagic intracranial malignant neoplasms: spin-echo MR imaging. Radiology 1987; 164:71-77.