Vang R, Heck K, Fuller G N, Medeiros L J
Department of Pathology and Laboratory Medicine, The University of Texas-Houston Medical School, USA.
Clin Neuropathol. 2000 Jan-Feb;19(1):41-4.
Granular cell tumor (GCT) is a benign neoplasm composed of a proliferation of round or polygonal cells that contain eosinophilic granular cytoplasm. The most common locations are tongue and subcutaneous tissue, but a variety of other sites may be involved including the central nervous system (CNS). Most CNS GCT arise in the pituitary, but rare cases involving brain and leptomeninges have been described. Extracranial GCT are usually S-100-positive, but those of the CNS, as well as the congenital variant of GCT, can be S-100-negative.
We report an incidental autopsy finding of a 2.5 mm GCT that arose in the intracranial meninges overlying the anterior superior cerebellar vermis.
The neoplasm had abundant eosinophilic, granular cytoplasm that was PAS-positive and diastase-resistant. Immunohistochemical studies showed that the neoplasm was positive for CD68 and negative for S-100, GFAP, EMA, and keratin. Thus, the immunophenotype is consistent with non-neural origin.
Although this lesion in this circumstance was of no clinical significance, knowledge of the occurrence of GCT at this site broadens the differential diagnosis of eosinophilic lesions of the leptomeninges.
颗粒细胞瘤（GCT）是一种良性肿瘤，由含有嗜酸性颗粒细胞质的圆形或多边形细胞增殖组成。最常见的部位是舌头和皮下组织，但也可能累及其他多种部位，包括中枢神经系统（CNS）。大多数中枢神经系统颗粒细胞瘤起源于垂体，但也有涉及脑和软脑膜的罕见病例报道。颅外颗粒细胞瘤通常S-100阳性，但中枢神经系统的颗粒细胞瘤以及颗粒细胞瘤的先天性变异型可能S-100阴性。
我们报告一例偶然尸检发现的2.5毫米颗粒细胞瘤，其起源于小脑上蚓部前方的颅内脑膜。
肿瘤具有丰富的嗜酸性颗粒细胞质，PAS阳性且耐淀粉酶。免疫组织化学研究显示，肿瘤CD68阳性，S-100、GFAP、EMA和角蛋白阴性。因此，免疫表型与非神经起源一致。
尽管在这种情况下该病变无临床意义，但了解该部位颗粒细胞瘤的发生拓宽了软脑膜嗜酸性病变的鉴别诊断范围。
