記住我
Abstract
Erdheim–Chester Disease (ECD) is a rare non-Langerhans form of systemic histiocytosis of unknown etiology with multiple organ involvement. It most commonly affects the long bones, lungs, heart, retroperitoneum, eyes, and kidneys and less commonly the brain and spinal cord. Although there are very few cases of supratentorial ECD mimicking intracranial meningioma reported in literature, to the best of our knowledge, there are no reports on ECD mimicking infratentorial pontocerebellar angle meningioma. The present study reports a case of ECD mimicking pontocerebellar angle meningioma. This study aimed to emphasize the importance of systemic evaluation using a multidisciplinary approach as well as the need for considering ECD as a differential diagnosis of xanthomatous meningioma.
Keywords: Erdheim–Chester disease, intracranialm, meningioma
How to cite this article: Introduction 
Erdheim–Chester disease (ECD) is a rare non-Langerhans form of systemic histiocytosis of unknown etiology with multiple organ involvement. It most commonly affects the long bones, lungs, heart, retroperitoneum, eyes, and kidneys and less commonly the brain and spinal cord. The disease was first described by William Chester in 1930. It is characterized by xanthomatous infiltration of tissues that show positive staining for CD68 and negative staining for CD1a.[1] Central nervous system (CNS) symptoms can be seen in 50% of the patients. The patients may manifest symptoms depending on their localization, but may also present with diabetes insipidus and neurohypophysitis.[2] Most patients also exhibit extraskeletal manifestations, including xanthelasma, interstitial lung disease, periaortic fibrosis, and retroperitoneal infiltration with perirenal and/or ureteral obstruction, renal failure, and exophthalmos.[3]
Although very few cases of supratentorial ECD mimicking intracranial meningioma have been reported in literature, to the best of our knowledge, there is no reported case of ECD with infratentorial localization mimicking pontocerebellar angle meningioma.
The present study reports a case of ECD mimicking pontocerebellar angle meningioma.
Case Report A 58-year-old male was admitted to our clinic with headache. He had a history of hypertension (HT) and chronic kidney disease (CKD). On magnetic resonance imaging (MRI) of the brain, a 28 × 38 mm mass in the left pontocerebellar angle with homogeneous contrast enhancement and an isointense and slightly hypointense appearance on T1- and T2-weighted images, respectively, was observed. There was evidence of compression on the brain stem and cerebellum along with associated edema, and the findings were consistent with those of a meningioma [Figure 1] and [Figure 2]. The patient underwent a left occipital craniotomy for total excision of the mass. Histopathological examination revealed a lesion containing diffuse histiocytic cells with foamy cytoplasm and local foci of lymphocytic infiltration. The cells forming the lesion showed scattered multinucleation, and eosinophilic cytoplasm were observed in some areas. Immunohistochemical examination revealed extensive reactivity for CD163 and CD68 in histiocytes, SSTR2A and PR (progesterone receptor) reactivity in a small number of cells, and no reactivity for EMA and CD1a [Figure 3]. The patient was diagnosed as having metaplastic meningioma with xanthomatous changes (World Health Organization Grade 1) based on morphological and immunohistochemical findings. Approximately 1 year later, abdominal ultrasound performed because of the history of CKD revealed multiple hypocheoic metastatic masses encircling both the kidneys, the largest reaching 28 × 16 mm on the right side and 42 × 40 mm on the left side; on the observation of these lesions, the patient underwent an abdominal MRI. Masses consistent with ECD were observed in the perirenal region surrounding both the kidneys on the abdominal MRI. The masses appeared heterogeneously hyperintense and hypointense on T1- and T2-weighted images and showed minimal contrast enhancement after the injection of an intravenous contrast medium. A laparoscopic biopsy of the perirenal tissue of the left kidney was performed, and its pathological examination revealed fat necrosis and foamy histiocytic infiltration. Approximately 1 year after the final diagnosis, polypectomy was performed on observation of a polyp in the gastric fundus at an endoscopy performed due to iron deficiency anemia; microscopic examination suggested the diagnosis of gastric xanthoma. As abdominal imaging studies raised the suspicion of ECD, the pathology department was consulted for the re-assessment of all the findings. Considering the lipid-laden macrophages, lymphocytes, Touton-type giant cells, and somatic BRAF V600E positivity observed in all lesions, the findings were observed to be consistent with those in ECD.
Figure 1: Post-contrast axial MRI of the brain showing lesion of the pontocerebellar angle
Figure 2: Post-contrast coronal MRI of the brain showing lesion of the pontocerebellar angle
Figure 3: Extensive histiocytic infiltration among meningothelial cells. a: HE × 200: Histiocytes with Touton-type giant cells (Black arrow: Foamy histiocytes. Yellow arrow: Touton-type giant cells). b: CD163 × 200: Histiocytes showing strong CD163 expression. c: SSTR2A × 200: Some meningothelial cells showing membranous SSTR2A positivity (Red arrow: Focal area of SSTR2A positivity displaying a membranous staining pattern). d: PR (progesterone) ×400: Scattered meningothelial cells showing nuclear PR positivity (Blue arrow: Nuclear staining for PR) Discussion ECD is a rare histiocytic disorder. It usually involves the skeletal system, retroperitoneum, pulmonary system, and cardiovascular system. Skeletal involvement can be seen in 70%–80%, renal involvement in 29%, pulmonary system involvement in 20%–25%, ophthalmological involvement in 27%, and CNS involvement in 10%–15% of the patients. The incidence of the disease is higher in men over 40 years of age, and the disease has a female-to-male ratio of 1:3.[1],[2],[3],[4]
In the pathological examination of ECD, the classical appearance of foamy lipid-laden histiocytes and Touton-type giant cells are frequently observed. The specimens show positive immunohistochemical staining for CD68, whereas positive staining for S100 is rarely observed. BRAF V600E mutation has been observed in up to 50% of patients with ECD.[5]
The patients may be asymptomatic, but the disease can manifest with minimal bone pain. Usually the cause of pain is bilateral, symmetric long bone osteosclerosis. In addition, extraskeletal manifestations such as xanthelasma, interstitial lung disease, periaortic fibrosis, and retroperitoneal infiltration with ureteral obstruction, renal failure, and exophthalmos may also be observed. The most common CNS symptoms are diabetes insipidus, cerebellar syndromes, and headache, which is characterized by brain compression findings that may vary based on the location of the compression.[3]
There is no standard treatment for ECD. Current management strategies include the use of corticosteroids, cyclosporine, azathioprine, methotrexate, interferon-α, targeted therapies, surgery, and radiotherapy. Corticosteroids are usually the first line of treatment and can be very useful in controlling symptoms. The effectiveness of chemotherapy is quite limited. Surgical treatment involves the excision of the mass compressing the neurological structures for decompression. Radiotherapy alone or after surgery has been shown to be beneficial. Although the prognosis of ECD is variable, patients with extensive systemic disease have a worse prognosis. Death is usually due to respiratory or cardiac arrest.[1]
Although intracranial lesions of ECD are reported very rarely, they may be confused with meningiomas immunohistochemically and radiologically, and be misdiagnosed as in our case.[1],[4],[5],[6],[7] The present patient was diagnosed as having metaplastic meningioma exhibiting xanthomatous changes on histopathological examination. A Xanthomatous meningioma is a rare variant of meningioma and contains two different cell components: meningothelial and foamy cells.[8] In our case, histopathological findings, such as the histiocytic component staining positive for CD163 and CD68 along with the presence of cells staining positive for meningothelial markers PR and SSTR2A, were considered to be consistent with the findings of a xanthomatous meningioma.
The differential diagnosis of xanthomatous meningioma includes lipomatous meningioma and clear cell meningioma.[9] ECD was considered as the differential diagnosis when our patient was systemically evaluated.
Our literature search showed that there have been a total of five reported cases of ECD mimicking a meningioma. The cases have been classified according to the location of the lesion in these reports [Table 1]. According to the classifications, the lesions were at the supratentorial and parafalxial location in all of the cases mimicking meningiomas radiologically. To the best of our knowledge, our case is the first in literature mimicking pontocerebellar angle meningioma.
Table 1: Case Reports of Erdheim-Chester Disease mimicking meningioma in the CNSThis study aimed to emphasize the importance of systemic evaluation using a multidisciplinary approach and the need for considering ECD as a differential diagnosis of xanthomatous meningioma.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References 
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/ijpm.ijpm_1121_21
留言 (0)