Cerebral cholesterol granuloma: case report

Granuloma de colesterol cerebral: relato de caso

Cerebral cholesterol granuloma: case report

Granuloma de colesterol cerebral: relato de caso

Rodrigo Mendonça^I; Cleiton Schweitzer Peron^I; Marco Antônio Stefani^II; Pasquale Gallo^II

Serviço de Neurocirurgia do Hospital Cristo Redentor, Porto Alegre RS, Brazil

IMD, Neurosurgery Resident

IIMD, Neurosurgery Preceptor

ABSTRACT

Intracranial cholesterol granulomas are rare lesions, and have been registered in petrous apex region. The presence of an intracerebral cholesterol granuloma is an uncommun event. We report the case of a 20-years-old woman who undergone craniotomy for resection of a temporal mass. Pathologic examination show a cholesterol granuloma.

Key words: granuloma, foreign-body, cholesterol, brain diseases.

RESUMO

Granulomas de colesterol intracranianos são lesões raras, sendo observados na região do ápice petroso. A ocorrência de granuloma de colesterol intracerebral é um evento incomum. Relata-se o caso de mulher de 20 anos submetida a craniotomia para ressecção de processo expansivo temporal, com exame anátomo-patológico evidenciando um granuloma de colesterol.

Palavras-chave: granuloma de corpo estranho, colesterol, doenças cerebrais.

Cholesterol granulomas of the central nervous system are rare lesions and the petrous apex is the intracranial site most frequently involved. Cases of intracranial cholesterol granuloma have been reported associated with familial hypercolesterolemia and high serum lipid levels. With few cases reported in the literature, the pathogenesis of the event is until unclear.

The following report shows a case of a young woman with a temporal mass with cholesterol granuloma diagnosed in the pathologic examination.

CASE

A black 20 year-old woman, presented at our service due to severe progressive headache and drowsiness. Physical and neurologic examination were normal. Neuroimaging showed a heterogeneous cystic mass in the posterior right temporal lobe, extending to the ventricular trigone (Fig 1A, B, ^C). A temporal craniotomy was performed, and the lesion was resected completely. The post-operative period was uneventful. Pathologic examination was consistent with cholesterol granuloma. There was no dislipidemia nor familial hypercholesterolemia hystory. At 3-month follow-up, the patient resumed a normal life, with no complaints. The post-operative image shows no recurrence (^{Fig 1D}).

DISCUSSION

Intracranial cholesterol granulomata are rare lesions, and are thought to occur as a foreign body reaction against cholesterol crystals^1-4. Cholesterol granulomata occur in about 1 per 2–3 million population each year⁵. In the region of mastoid air cells, the mucosal swelling blockage of the pneumatic pathways to apical air cell system, leading to hypoxia and further tissue and blood cells necrosis. Trapped gas resorption results in a vacuum that triggers bleeding, and cholesterol crystals forms through anaerobic breakdown of blood products³. Another theory, the exposed marrow hypothesis, was postulated to explain the cholesterol granuloma formation ³.

The petrous apex is the most intracranial site frequently involved by cholesterol granulomata^2,5-7, followed by orbital bones^4,8,9. Further reports indicate that cholesterol granulomas account for 60% of petrous apex lesions ¹⁰.There are cases of xanthomas in the third ventricle, including associated with colloid cyst¹¹.

One case report was found concerned intracerebral localization of cholesterol granuloma¹, in a patient with familial hypercolesterolemia and high serum lipid levels, who presented with an asymptomatic cholesterol granuloma of the brain. Intracranial cerebral cholesterol granulomata have not been associated with genetic hypercholesterolemia^5,6, with only one previous case linked to homozygous FH¹². In the present case, the patient was not dislipidemic, neither history of familial hypercolesterolemia was present. There was no history of pregress neurologic illness, such as cerebral hemorhage or traumatic brain injury, wich could explain the presence of blood degradation products in the cerebral parenchyma. Thus, no risk factor could be assesed.

Imaging of the lesions with computed tomography and magnetic resonance imaging can help differentiate cholesterol granulomas from other lesions on the basis of a characteristic appearance. In general, the lesion is hyperintense in both T1 and T2-weight images, because of presence of lipid. A dark signal rim in T2, suggestive of hemosiderin, also could be seen.

The treatment of cholesterol granuloma is the surgical excision, with very low incidence of recurrence in cases with complete removal ⁴.

Received 1 October 2006, received in final form 16 January 2007. Accepted 13 March 2007.

Dr. Rodrigo Mendonça - Rua Domingos Rublo 20 / 260 - 91040-000 Porto Alegre RS - Brasil.

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Publication Dates

• Publication in this collection
  24 July 2007
• Date of issue
  June 2007

History

• Accepted
  13 Mar 2007
• Received
  01 Oct 2006
• Reviewed
  16 Jan 2007