10 Hypothalamic Lesions on Magnetic Resonance Imaging

CLINICAL IMAGAGINGAN ATLAS OF DIFFERENTIAL DAIGNOSIS

EISENBERG

DR. Muhammad Bin Zulfiqar PGR-FCPS III SIMS/SHL

• Fig SK 10-1 Glioma. (A) Sagittal T1-weighted image in a 2-year-old emaciated and hyperactive girl shows a large midline mass involving the optic chiasm (straight arrow) and hypothalamus (curved arrow). (B) Coronal contrast-enhanced T1-weighted image shows nonuniform enhancement of the tumor, which extends superiorly to the foramen of Monro and causes obstructive hydrocephalus.21

• Fig SK 10-2 Germinoma. Sagittal T1-weighted scans before (A) and after (B) administration of contrast material in an 18-year-old man with diabetes insipidus show enhancing masses in the floor of the anterior third ventricle (straight black arrow) and pineal region (curved arrow). The optic chiasm (white arrow) is not involved.21

• Fig SK 10-3 Primary CNS lymphoma. (A) Sagittal and (B) axial T1-weighted images after injection of contrast material show enhancing mass lesions in the hypothalamus (arrow) and left thalamus (arrowhead).21

• Fig SK 10-4 Hamartoma. Coronal (A) T1-weighted and (B) T2-weighted scans in a 5-year-old girl with precocious puberty show a midline hypothalamic mass (arrows) bulging into the inferior floor of the third ventricle. The lesion is isointense on both images and is centered in the region of the tuber cinereum.21

• Fig SK 10-5 Langerhans cell histiocytosis. (A) Initial sagittal T1-weighted image after injection of contrast material in a 9-year-old boy with diabetes insipidus shows a large enhancing hypothalamus mass splaying the cerebral peduncles. (B) Corresponding image 3 weeks after low-dose radiation treatment shows a significant decrease in size of the lesion.21

• Fig SK 10-6 Metastasis. Sagittal T1-weighted contrast image demonstrates a large clival mass with destruction of the sella and invasion of the suprasellar region. Note the small enhancing hypothalamic mass (arrow) representing metastasis from breast cancer.22

• Fig SK 10-7 Hemangioblastoma. Coronal T1-weighted contrast image indicates that the complex mass contains cystic components with marginal enhancement (short arrow) and an intensely enhancing mural nodule (long arrow).22

• Fig SK 10-8 Choristoma. Sagittal T1-weighted contrast image shows a well-defined suprasellar mass (arrow). Initially isointense relative to brain, the mass shows inhomogeneous enhancement.22

• Fig SK 10-9 Craniopharyngioma. Coronal T1-weighted contrast image shows a lobulated suprasella tumor with intrasellar extension. The tumor is formed predominantly of multiple cysts with varying signal intensities that show thin mural enhancement (arrows). Note the associated asymmetric dilatation of the lateral ventricle.22 (Courtesy of Yasser Regab, M.D., Cairo, Egypt.)

• Fig SK 10-10 Dermoid cyst. (A) Sagittal T1-weighted image shows a well-defined hyperintense lesion (arrow) at the floor of the hypothalamus, posterior to the infundibular stalk. (B) On a coronal fat-suppressed T1-weighted image, the lesion (arrowheads) exhibits suppressed signal intensity, a finding that indicates fat deposition.22

• Fig SK 10-11 Rathke's cleft cyst. Coronal T1-weighted image shows a well-defined intra- and suprasellar lesion that displaces the optic chiasm upward (arrowheads). The high signal intensity reflects the high concentration of mucopolysaccharides within the mass.22 (Courtesy of Yasser Regab, M.D., Cairo, Egypt.)

• Fig SK 10-12 Colloid cyst. Sagittal T1-weighted image shows a well-defined, homogeneously hyperintense suprasellar cyst (curved arrow) that displaces the optic chiasm upward (straight arrow). Intrasellar extension compresses the pituitary gland (arrowhead).22

• Fig SK 10-13 Encephalitis. Coronal T2-weighted image shows a hyperintense area in the thalamic-hypothalamic region (arrow) that corresponds to edematous changes.22 (Courtesy of Yasser Regab, M.D., Cairo, Egypt.)

• Fig SK 10-14 Sarcoidosis. (A) Sagittal T1-weighted image in a black woman with recent onset of visual difficulties shows abnormal thickening in the hypothalamic region (arrows) involving the tuber cinereum, mamillary bodies, and infundibulum. (B) After a 3-week course of steroids, a repeat sagittal scan shows dramatic resolution with a return to normal of hypothalamic region anatomy. Note the mamillary bodies (curved arrow), tuber cinereum (straight arrow), and infundibulum (arrowhead).21

• Fig SK 10-15 Ectopic posterior pituitary gland. Coronal T1-weighted image in a young boy with short stature shows a hyperintense, oblong nodule (arrow) in the inferior portion of the tuber cinereum. Pituitary tissue within the sella does not show high signal in its posterior portion, and there is no evidence of an infundibulum connecting the pituitary gland to the hypothalamus.21

• Fig SK 10-16 Wernicke's encephalopathy. Sagittal T1-weighted image in an elderly alcoholic man shows striking atrophy of the mamillary bodies.21