Intracerebral Langerhans cell histiocytosis

Clinical History

A young woman presented with intermittent headaches and dizziness which she had had for 2–3 months. She also complained of having a dull pain behind her left eye. On clinical examination, she was found to have bilateral papilloedema.

Imaging Findings

A young woman presented with intermittent headaches and dizziness which she had had for 2–3 months. She also complained of having a dull pain behind her left eye. On clinical examination, she was found to have bilateral papilloedema. Magnetic resonance imaging that was done, showed an enhancing mass lesion in the left frontal lobe with a surrounding oedema being present. The imaging features were found to be non-specific but were most suggestive of a high grade glioma. The differential diagnosis included a solitary metastasis from a malignant melanoma or a lymphoma, and less likely a cerebral abscess or parasitic infection. At resection biopsy, the lesion was seen to be attached to the dura. A histological analysis done, revealed collections of eosinophils and Langerhans cells staining positively with CD1a, and a diagnosis of intracerebral Langerhans cell histiocytosis was made. Other investigations, including a skeletal survey and an HRCT of the chest, showed no evidence of skeletal or pulmonary involvement with Langerhans cell histiocytosis.

Discussion

Central nervous system disease in Langerhans cell histiocytosis (LCH) is said to be a rare condition which typically presents with multisystem disease, and is characterized by a granulomatous infiltration of the lungs, bones, skin, lymph nodes, brain and endocrine glands. The central nervous system (CNS) manifestations and MRI findings of LCH are well described by Grois et al., following a retrospective review of the clinical and imaging data in 38 patients. There are three main patterns for the occurrence of the CNS disease. 1) Disorders of the hypothalamus-pituitary system: This is the most affected area of the CNS, and Diabetes Insipidus is the most common manifestation due to the involvement of the posterior pituitary. Symptoms of hypothalamic involvement include disturbances of sleep, appetite and temperature regulation, while anterior pituitary disease presents with growth failure, amenorrhoea, hypothyroidism or hypocortisolism. Morphologic changes are best demonstrated by MRI with gadolinium, and include a thickening of the infundibulum, partially empty sella with the absence of the posterior pituitary bright spot, and suprasellar mass lesions. 2) Space occupying lesions, which may arise from the bone, meninges or choroid plexus, and usually present with symptoms of a raised intracranial pressure such as headaches, vomiting and papilloedema. These lesions may occur without other evidence of LCH (as seen in this case report) and typically display uniform contrast enhancement on MRI. 3) Cerebellar–pontine lesions: This is the second most common site of involvement after the hypothalamic-pituitary axis. Symptoms usually start with abnormal reflexes, gait disturbance and nystagmus, and can progress to profound ataxia. Pontine symptoms, including dysarthria, dysphagia and other cranial nerve deficits, may ensue, leading to severe CNS deterioration. The most frequently observed findings on MRI are bilateral symmetrical changes in the cerebellum without enhancement. Interestingly, cerebellar lesions were not seen as an isolated finding in the study performed by Grois et al. The majority of patients display more than one type of lesion. In the study done by Grois et al., 87% of patients had more than one type of lesion, and 72% of patients had multisystem disease. The histopathology of cerebral LCH—based on a review of autopsy cases in 1979, Kepes proposed that LCH cells arise from the adventitial cells of blood vessels, resulting in perivascular aggregates of histiocytes. These evolve into larger granulomatous masses containing foamy histiocytes and eosinophils as well as microglial cells, lymphocytes and plasma cells. The lesions later progress to fibrosis and gliosis. Langerhans cells characteristically show a positive staining with S100 and CD1a (as seen in this case report) and contain Birbeck granules (tennis-racket-shaped inclusion bodies seen on electron microscopy). Treatment strategies—the appropriate therapeutic approach depends on the type, site and the course of the CNS lesions, and the disease status of LCH elsewhere. Extraparenchymal mass lesions usually have a good prognosis after surgery. Systemic chemotherapy or irradiation may be indicated if the risk of surgery is too great. In patients with mass lesions of the hypothalamus-pituitary axis, the role of surgery and radiotherapy has to be evaluated, bearing in mind that established diabetes insipidus is unlikely to be reversible! In patients with progressive neurologic degeneration, no treatment regimen has shown a clearly positive effect, and irradiation may be harmful rather than beneficial.

Differential Diagnosis List

Final Diagnosis

Intracerebral Langerhans cell histiocytosis.

URL:	https://www.eurorad.org/case/2586
DOI:	10.1594/EURORAD/CASE.2586
ISSN:	1563-4086