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Neuroradiology Case of the Week

Case 157

Ruusu (Rose) Ketonen and PL Westesson MD, DDS, PhD

Clinical Presentation:  The patient is a 44-year-old female with a history of bilateral mastectomy for breast cancer seven years earlier. She has gone through radiation and chemotherapy following bone marrow transplantation and has been disease free for the last five years. Beside cancer she has had Hashimoto thyroiditis and multinodular goiter. She comes now to consultation because of headaches starting from the suboccipital region which she has noticed to have started a year ago. She has also blurry vision and chronically poor balance.

Radiological Findings:  The brain MR images demonstrate a bright T2, non-enhancing lesion in the right cerebellar hemisphere with mass effect on the fourth ventricle, which is effaced but not totally obstructed. There is a minimal periventricular edema due to compensated hydrocephalus. There is also cerebellar tonsillar herniation that reaches the level of C2-3 intersection as seen in Chiari I malformation.

Differential diagnosis includes Lhermitte-Duclos disease (dysplastic cerebellar gangliocytoma) versus metastatic disease.

Biopsy findings: Grossly distorted and enlarged cerebellar folia consistent with Lhermitte-Duclos disease.

Diagnosis: Cowden’s Syndrome with Lhermitte-Duclos disease

Clinical Discussion:  Lhermitte-Duclos Disease (LDD), manifests usually at the third or fourth decade of life. It has the features both of a neoplasm and a hamartoma. Macroscopically, there is a widening of the cerebellar folia which efface the sulci. The histopathological findings consists of widening of the molecular layer with abnormal myelination that is occupied by abnormal ganglion cells, absence of the Purkinje cell layer and hypertrophy of the granular cell layer, with atrophy of the cerebellar white matter.
     LDD is often associated with Cowden’s disease, a hamartoma syndrome, which manifests as mucocutaneous lesions, macrocephaly, and increased frequency of hamartomas and neoplasia in the CNS, breast, thyroid, colon, and genitourinary tract. Both conditions are linked to mutations in the PTEN gene, which controls cell apoptosis, migration and differentiation.
      The clinical symptoms are that of increased intracranial pressure and hydrocephalus which are headaches and nausea. The less common symptoms are ataxia, visual disturbances and other cranial nerve palsies.

Radiological Discussion:  LDD presents on the MR as a nonenhancing unilateral lesion in the cerebellum with mass effect on surrounding structures. The lesion is hypointense on the T1 weighted images and hyperintense on the T2-weighted images with alternating parallel hyperintense and isointense stripes which are characteristic for the disease. These bands correspond to the inner molecular layer and the granular layer of the cerebellum. Loss of central white matter within the folia also contributes to the appearance. Tonsillar herniation and hydrocephalus are quite common and are caused by the mass effect of the lesion to the adjacent cerebellar parenchyma. T1-images are usually unremarkable, because no contrast enhancement is detected as there is no significant disturbance in the blood-brain barrier.
      On the DWI the high signal intensity is due to T2-shine-through effect, which can be detected by a ADC-map showing normal water diffusion. The image will appear then as isointense.

References:

1. Moonis G, Ibrahim M, Melhem ER. Diffusion-weighted MRI in Lhermitte-Duclos disease: report of two cases. Neuroradiology. 2004 May;46(5):351-4. [Medline]
2. Abel TW, Baker SJ, Fraser MM, Tihan T, Nelson JS, Yachnis AT, Bouffard JP, Mena H, Burger PC, Eberhart CG. Lhermitte-Duclos disease: a report of 31 cases with immunohistochemical analysis of the PTEN/AKT/mTOR pathway.
   J Neuropathol Exp Neurol. 2005 Apr;64(4):341-9. Review. [Medline]
3. Klisch J, Juengling F, Spreer J, Koch D, Thiel T, Buchert M, Arnold S, Feuerhake F, Schumacher M. Lhermitte-Duclos disease: assessment with MR imaging, positron emission tomography, single-photon emission CT, and MR spectroscopy. AJNR Am J Neuroradiol. 2001 May;22(5):824-30. [Medline]
4. Lok C, Viseux V, Avril MF, Richard MA, Gondry-Jouet C, Deramond H, Desfossez-Tribout C, Courtade S, Delaunay M, Piette F, Legars D, Dreno B, Saiag P, Longy M, Lorette G, Laroche L, Caux F; Cancerology Group of the French Society of Dermatology. Brain magnetic resonance imaging in patients with Cowden syndrome. Medicine (Baltimore). 2005 Mar;84(2):129-36. [Medline]
5. Robinson S, Cohen AR. Cowden disease and Lhermitte-Duclos disease: characterization of a new phakomatosis. Neurosurgery. 2000 Feb;46(2):371-83. [Medline]