1. MedPix Medical Image Database COW - Case of the Week Case Contributor: Neuroradiology Learning File - © ACR Affiliation: ACR Learning File®

2. MedPix No: 2819 - History Pt Demographics: Age = 15 y.o. Gender = boy 15-year-old male with 2-year history of generalized seizures (Films.1-.7). Downloaded by (-1)

3. MedPix No: 2819 - EXAM & LABS

4. Film 1 On admission, a CT of the brain was performed without intravenous contrast. In the left temporal and parietal lobe a large irregular lesion with bulky calcifications and multiple cystic components was noted. Mass effect was demonstrated with compression of the left lateral ventricle and slight displacement of the midline structures towards the right (Film 1, top row). Postcontrast CT revealed small areas of contrast enhancement involving the solid components of the lesion adjacent to the calcifications (Film 1, bottom row). Downloaded by (-1)

5. Film 2 MR examination was subsequently performed both with and without intravenous Gadopentetate Dimeglumine. Axial short TR/TE sequences (600/20) without intravenous contrast revealed areas of slightly shortened T1 relaxation best seen adjacent to the left atrium (Film 2, top row). The lesion had multiple areas of hypointensity similar to CSF signal intensity and was irregular in shape. On the proton-density and long-TR- weighted sequences (1966/20; 1966/100), the aforementioned cystic areas revealed hyperintense signals. Again noted was slight shift of the midline structures towards the right with compression of the left cerebral peduncle as well as a trapped left temporal horn (Film 2, bottom row). Downloaded by (-1)

6. Film 3 Multiple areas of hypointensity within the lesion are noted on the long TR/TE images corresponding to the calcifications noted on CT. A minimal surrounding zone of hyperintensity is seen consistent with edema. After intravenous contrast administration there was a larger area of irregular enhancement not appreciated on the postcontrast CT exam (Film 3). Several of the cystic components did not demonstrate enhancement (Film 4). Downloaded by (-1)

7. Film 4 Multiple areas of hypointensity within the lesion are noted on the long TR/TE images corresponding to the calcifications noted on CT. A minimal surrounding zone of hyperintensity is seen consistent with edema. After intravenous contrast administration there was a larger area of irregular enhancement not appreciated on the postcontrast CT exam (Film 3). Several of the cystic components did not demonstrate enhancement (Film 4). Downloaded by (-1)

8. Film 5 Preoperative angiography (Films 5, 6, 7) revealed the left temporal parietal lobe lesion to be avascular. There is mass effect and displacement of the left temporal artery, left angular artery and insular vessels. (Technical note: Please note on the AP projection that the marker should not have been placed over the image.) Downloaded by (-1)

9. Film 6 Preoperative angiography (Films 5, 6, 7) revealed the left temporal parietal lobe lesion to be avascular. There is mass effect and displacement of the left temporal artery, left angular artery and insular vessels. (Technical note: Please note on the AP projection that the marker should not have been placed over the image.) Downloaded by (-1)

10. Film 7 Preoperative angiography (Films 5, 6, 7) revealed the left temporal parietal lobe lesion to be avascular. There is mass effect and displacement of the left temporal artery, left angular artery and insular vessels. (Technical note: Please note on the AP projection that the marker should not have been placed over the image.) Downloaded by (-1)

11. Film 8 Another case, also that of a 14-year-old with ganglioglioma, is shown on Film 8. A contrast- enhanced CT (Film 8) shows a large cystic mass in the right temporal and parietal lobes. The mass is mainly of low density (cystic at surgery) and contains large areas of calcification in its posterior and superior aspect. Downloaded by (-1)

12. FINDINGS On admission, a CT of the brain was performed without intravenous contrast. In the left temporal and parietal lobe a large irregular lesion with bulky calcifications and multiple cystic components was noted. Mass effect was demonstrated with compression of the left lateral ventricle and slight displacement of the midline structures towards the right (Film 1, top row). Postcontrast CT revealed small areas of contrast enhancement involving the solid components of the lesion adjacent to the calcifications (Film 1, bottom row).MR examination was subsequently performed both with and without intravenous Gadopentetate Dimeglumine. Axial short TR/TE sequences (600/20) without intravenous contrast revealed areas of slightly shortened T1 relaxation best seen adjacent to the left atrium (Film 2, top row). The lesion had multiple areas of hypointensity similar to CSF signal intensity and was irregular in shape. On the proton-density and long-TR- weighted sequences (1966/20; 1966/100), the aforementioned cystic areas revealed hyperintense signals. Again noted was slight shift of the midline structures towards the right with compression of the left cerebral peduncle as well as a trapped left temporal horn (Film 2, bottom row).Multiple areas of hypointensity within the lesion are noted on the long TR/TE images corresponding to the calcifications noted on CT. A minimal surrounding zone of hyperintensity is seen consistent with edema. After intravenous contrast administration there was a larger area of irregular enhancement not appreciated on the postcontrast CT exam (Film 3). Several of the cystic components did not demonstrate enhancement (Film 4).Preoperative angiography (Films 5, 6, 7) revealed the left temporal parietal lobe lesion to be avascular. There is mass effect and displacement of the left temporal artery, left angular artery and insular vessels. (Technical note: Please note on the AP projection that the marker should not have been placed over the image.)Another case, also that of a 14-year-old with ganglioglioma, is shown on Film 8. A contrast-enhanced CT (Film 8) shows a large cystic mass in the right temporal and parietal lobes. The mass is mainly of low density (cystic at surgery) and contains large areas of calcification in its posterior and superior aspect.

13. DIFFERENTIAL DIAGNOSIS What is your Differential Diagnosis?

14. Diagnosis: Ganglioglioma. Dx Confirmed by:

15. DISCUSSION Gangliogliomas are rare tumors that account for only 0.4-0.9% of primary brain neoplasias. Unlike the more common gliomas, these tumors contain both glial and neuronal elements. Even though at times the terms *ganglioglioma* and *gangliocytoma* are used interchangeably, the latter refers to brain neoplasias that contain exclusively neuronal components. Gangliogliomas are seen in all age groups and are slightly more common in males. These tumors occur anywhere in the brain, spinal cord, and even in the optic nerves. The most common locations are the temporal lobes (38%) and the cerebellum (22%). The initial clinical presentation usually consists of nonspecific symptoms, which probably reflect the slow-growing nature of the tumor. Gangliogliomas usually behave in a benign fashion and have a relatively favorable prognosis. - - By either CT or MR, approximately 40% of lesions are cystic. These are low density by CT and on MR show decrease signal intensity on T1-weighted images and high signal intensity on T2-weighted images. The remaining 60% are solid and by CT they can be: low density (38%), isodense (15%), hyperdense (15%), or of mixed densities (49%). On MR, T1-weighted images generally show the lesions to have a variable nonspecific appearance. On T2- weighted images gangliogliomas are slightly hyperintense. Following iodinated contrast administration, CT shows enhancement in half of gangliogliomas. Calcifications are seen in 30% of cases (especially in the cystic lesions). Cerebral angiography shows these tumors to be avascular. - - Ganglioglioma is not usually considered in the radiographic preoperative differential diagnosis of intracranial masses; however, it is being recognized by pathologists with increasing frequency. Ganglioglioma should be considered when a mainly cystic mass (especially with large calcifications) is present in the temporal lobes or in the cerebellum, or when a poorly defined, slightly enhancing mass is present in the temporal lobes.