Recurrent primary leptomeningeal astrocytoma of the lumbosacral spinal cord resembling schwannoma. A case report

Primary leptomeningeal astrocytoma has been considered to be derived from ectopic glial cells in the leptomeninges. A case of recurrent primary leptomeningeal astrocytoma of the lumbosacral spinal cord is described. The original tumor was localized in the extramedullary space at the level of the 12th thoracic vertebra, and was solely composed of interlacing bundles of monomorphous spindle-shaped cells. The tumor was therefore diagnosed as schwannoma. The recurrent tumor removed one year after the first operation showed two distinct histologic patterns with increased nuclear atypia and mitosis. Namely, both schwannoma-like areas and astrocytomatous areas were observed. Silver impregnation clearly demonstrated an alveolar pattern in the schwannoma-like area. Immunohistochemically, the tumor cells revealed a positive reaction for glial fibrillary acidic protein. This case particularly emphasizes the usefulness of silver impregnation in differential diagnosis from schwannoma.     

Extracerebral leptomeningeal astrocytoma mimicking a meningioma

A 49-year-old woman with a two-year history of headaches that became progressively more frequent was found on computerized tomographic scan to have a dense, enhancing right frontoparietal mass. The tumor mimicked a meningioma in that it indented the inner table of the skull, was well demarcated from the underlying brain, and microscopically lacked the fibrillated cell processes and background that characterize astrocytomas. The 80- to 100-A cytofilaments were sparse and seen in few cells. It was only by the immunoperoxidase stain for glial acidic protein that the diagnosis of an extra-axial leptomeningeal astrocytoma was established.     

Immature cerebellar astrocytoma in an infant

A case of immature cerebellar astrocytoma in a 1 year and 4 months-old girl was described. The tumor consisted mainly of closely packed relatively uniform round cells with prominent intervening capillaries. Although tumor cells showed negative GFA (glial fibrillary acidic protein) immunoreactivity, demonstration of occasional bundles of 10 nm intermediate filaments (glial filaments) in cytoplasm on electron microscopy confirmed the diagnosis of astrocytoma. Differential diagnosis to hemangioblastoma, astroblastoma, and primitive neuroectodermal tumor was discussed.     

IMMATURE CEREBELLAR ASTROCYTOMA IN AN INFANT

A case of immature cerebellar astrocytoma in a 1 year and 4 months-old girl was described. The tumor consisted mainly of closely packed relatively uniform round cells with prominent intervening capillaries. Although tumor cells showed negative GFA (glial fibrillary acidic protein) immunoreactivlty, demonstration of occasional bundles of 10 nm intermediate filaments (glial filaments) in cytoplasm on electron microscopy confirmed the diagnosis of astrocytoma. Differential diagnosis to hemangioblastoma, astroblastoma, and primitive neuroectodermal tumor was discussed.     

Astrocytoma with granular cell tumor-like changes. Report of a case with histochemical and ultrastructural characterization of granular cells

A peculiar case of astrocytoma showing a histological appearance similar to granular cell tumor was reported. The tumor consisted of large round cells containing numerous intracytoplasmic eosinophilic granules, partially intermingled with atypical astrocytes, and part of it showed a transition to distinct areas of fibrillary astrocytoma. The granules were periodic acid-Schiff-positive (with resistance to diastase digestion), negative for fat stains and revealed lectin-binding patterns similar to those in granular cell tumor. Ultrastructurally the granules were partially membrane-bound, dense bodies compatible with secondary lysosomes. It was suggested that the granular cells were of astrocytic origin because of their immunoreactivity for glial fibrillary acidic protein (GFAP) and ultrastructural observation of intermediate filaments corresponding to GFAP.     

Pituicytoma: Review of commonalities and distinguishing features among TTF-1 positive tumors of the central nervous system

Pituicytoma is a rare low-grade glial neoplasm that originates in the distribution of the neurohypophysis, including the posterior pituitary lobe and infundibular stalk. The tumor cells resemble pituicytes, which are specialized glial cells of the neurohypophysis. Pituicytoma can be misdiagnosed pre-operatively as a pituitary adenoma due to overlapping clinical and neuroimaging features between these two entities. Pituicytoma can also mimic other neoplasms of the sellar and parasellar regions microscopically – meningioma, schwannoma and pilocytic astrocytoma – and shares immunohistochemical expression of TTF-1 with spindle cell oncocytoma and granular cell tumor of the sellar region, suggesting a common histogenesis. In this short review, we present the key features of pituicytoma, discuss commonalities and distinguishing features from other neoplasms of the sellar and parasellar regions and highlight the importance of recognizing this tumor entity for clinical and surgical management.     

Retroperitoneal schwannoma with features of gastrointestinal schwannoma. A case report

A case of retroperitoneal schwannoma with histological features of gastrointestinal (GI) schwannoma occurring in a 67-year-old woman is reported. The tumor was composed of spindle cells with focal pseudoatypism and it showed several features typical of gastrointestinal-type schwannoma such as lymphocytic infiltration, peripheral cuff of lymphocytes, lack of Antoni A pattern, and absence of thick walled vessels. Immunohistochemically, the tumor showed diffuse reactivity for S100 protein and glial fibrillary acidic protein. The authors discuss a phenotypical similarity of the lesion with GI schwannoma as well as the possible existence of GI-type schwannoma outside the tubal GI tract.     

Desmoplastic cerebral astrocytoma of infancy intermingling with atypical glial cells

Despite the rarity of desmoplastic cerebral astrocytoma of infancy (DCAI), it has distinct clinical and pathological features. The present case is a typical DCAI except for its detection and operational age and intermingling with pleomorphic glial cells. In this case, although a cystic lesion of the right temporal lobe was noticed when the patient was 6 months old, it was not regarded as a tumor and wasn't removed until he was 9 years old. It is quite unusual that a DCAI was able to exist in the cerebrum for 9 years. However, no metastasis occurred and distinct macroscopic and microscopic features of the tumor were not different from typical DCAI except for an intermingling with pleomorphic glial cells. Furthermore, even in the pleomorphic areas, the absence of necrosis and an MIB-1 index of 2.9% indicated non-aggressive growth. These features of the present case may provide additional information as to the character of DCAI, which generally has a favorable prognosis.     

Minigemistocytic astrocytoma with frequent apoptoses: Analysis of tumor growth

A rare glial tumor known as 'minigemistocytic astrocytoma (gliofibrillaty oligodendroglioma)' is reported in a 73 year old Japanese male. A low-density area found by computed tomography and thought to be an operative scar remaining after hematoma in the right frontal lobe of the cerebrum had been followed for 10 years. This area, however, had been accompanied by a cyst for 2 years and had developed gradually for 1 year prior to dissection. The tumor was poorly demarcated from the surrounding normal tissue macroscopically at operation. Microscopically, the tumor consisted of small gemistocytic cells in uniform sheets intersected by a small vascular stroma with frequent eosinophilic granular bodies, mitoses and apoptotic bodies. lmmunohistochemical examination for glial fibrilliary acidic protein (GFAP) revealed remarkable positive reactivity in the perinuclear cytoplasm, but no immunoreactivity for vimentin or Leu 7 was found. Electron microscopically, rich filaments amngfd in parallel bundles were found in the neoplastic cells. These histological findings are closely consistent with those of previously reported minigemistocytic astrocytoma cases. The GFAP-rich minigemistocytic astrocytoma with granular bodies and frequent mitoses in the present case is considered to indicate a higher degree of astrocytic differentiation and malignant potential than previous cases. The frequent apoptoses, however, might inhibit tumor growth in this case.     

毛细胞黏液样型星形细胞瘤的临床病理学观察

目的探讨毛细胞黏液样型星形细胞瘤的临床病理学特点。方法观察3例毛细胞黏液样型星形细胞瘤的光镜形态,采用EnVision法免疫组织化学标记胶质纤维酸性蛋白（GFAP）、CD34、Ki-67,并结合文献复习分析其生物学行为。结果3例均为女性,年龄分别为9个月、10岁和19岁。1例发生于视交叉,2例发生于第三脑室（近鞍区部位）。镜下由双极性的梭形细胞组成,间质内含有大量的黏液。肿瘤内的血管明显增生,部分区域内瘤细胞显示以血管为中心性生长。3例切片内均未见到经典型毛细胞星形细胞瘤中的双相性形态,也未见Rosenthal纤维和嗜酸性颗粒小体。免疫标记显示,瘤细胞强阳性表达GFAP,瘤细胞增殖指数（Ki-67）〈1％。CD34标记显示清晰瘤内增生的血管。结论毛细胞黏液样型星形细胞瘤是毛细胞星形细胞瘤的一种独特亚型,在组织学上与毛细胞星形细胞瘤有不同之处,临床上较毛细胞星形细胞瘤更具有侵袭性。部分病例也可发生于儿童和青少年。GFAP标记有助于该瘤的诊断和鉴别诊断。     

May 1999--16 year old male with an unexpected MRI finding.

Four years after resection of a supratentorial pilocytic astrocytoma this 16-year-old boy displayed widespread leptomeningeal seeding. Although the primary tumor lacked contrast enhancement, the multiple metastatic nodules were markedly contrast enhancing. Both the initial and disseminated tumor were consistent with a pilocytic astrocytoma. He was treated with vincristin and carboplatinum and the tumor was stable up to Dec. 1998. Dissemination of low-grade intracranial astrocytoma in children occurs in only 4%. It is not a sign of malignancy.The present case is similar to previously published cases. The prognosis of these patients might be quite favorable when treated with radiotherapy and/or chemotherapy.     

Vestibular schwannoma with malignant transformation: a case report.

We describe a rare case of malignant transformation in a vestibular schwannoma in a 33-yr-old woman. She presented herself with headache, tinnitus, and hearing loss and underwent posterior fossa explorations three times during the short period of 3 months. The clinicopathological features of the original tumor were typical of benign vestibular schwannoma. Despite a complete microsurgical excision, two months later, the tumor recurred locally with a rapid increase in size causing a progressive worsening of neurological symptoms. A diagnosis of malignant schwannoma was made for the recurrent tumor on the basis of the microscopic findings of high cellularity, moderate pleomorphism, and the presence of mitotic cells. Repeat magnetic resonance imaging performed a month after the second surgery unexpectedly showed definite tumor enlargement. She remained clinically stable following the third debulking of the tumor and adjuvant radiotherapy. We propose that this recurrent tumor represent malignant transformation from a benign vestibular schwannoma which was an unusual occurrence in a patient without neurofibromatosis.     

微囊性/网状神经鞘瘤的临床病理特点

目的 探讨微囊性/网状神经鞘瘤的形态学和免疫表型特点及鉴别诊断.方法 收集1例发生在颈椎的微囊性/网状神经鞘瘤,根据HE切片和免疫组织化学染色观察形态学及免疫表型特点,并复习相关文献.免疫组织化学采用EnVision两步法.结果 患者男,35岁,因颈部不适就诊,影像学检查见颈5椎体破坏,肿块周围有硬化带,考虑良性病变.手术中见椎体破坏,肿瘤无包膜,结节状,质软,大小约3.5 cm×3.0 cm×1.8 cm.镜下观察,肿瘤无明确包膜,结节状分布,细胞学明确呈两种形态,一种类似于普通神经鞘瘤,但局灶细胞显示明显多形性,似神经鞘瘤伴退变,另一区域呈上皮样细胞,呈网状或蕾丝花边样排列,间质伴显著黏液变性.免疫组织化学示两种区域细胞表达一致,强阳性表达波形蛋白、S-100蛋白、胶质纤维酸性蛋白和神经元特异性烯纯化酶,散在表达CD68、CD10和Ki-67,不表达细胞角蛋白、上皮细胞膜抗原、神经微丝、癌胚抗原、平滑肌肌动蛋白、雌孕激素受体和p53.结论 微囊性/网状神经鞘瘤是神经鞘瘤的一种特殊形态学变型,临床罕见,发生在骨内更为罕见,熟悉其组织学特点和免疫表型有助于与脊索瘤和其他黏液性肿瘤或肉瘤鉴别.     

骶骨神经源性肿瘤临床病理分析

目的:探讨骶骨神经源性肿瘤的临床病理学特征、诊断及鉴别诊断.方法:收集21例发生在骶骨的神经源性肿瘤,通过光镜观察及免疫组织化学分析其临床、影像学、病理学特征、免疫表型、鉴别诊断及手术预后.结果:21例中女15例,男6例,平均年龄44.9岁.临床上以骶尾部疼痛为主,影像学上表现为骶骨或骶骨及骶前肿块.神经鞘瘤17例,其中经典型神经鞘瘤8例,富于细胞神经鞘瘤9例.神经纤维瘤3例,节细胞神经瘤1例.累及骶骨的肿块,多数有不同程度的骨质破坏.免疫表型:神经鞘瘤均弥漫强阳性表达S-100蛋白,不表达NF.神经纤维瘤和节细胞神经瘤表达NF.富于细胞神经鞘瘤有4例为复发病例,平均复发时间6.5年.经典型神经鞘瘤和神经纤维瘤各有1例为复发病例.结论:骶骨神经源性肿瘤是少见肿瘤,以良性多见.各病理类型及亚型在形态学和生长方式上有一定的差异,故诊断时应明确病理类型及亚型,以供临床随访、治疗.     

Melanotic Schwannoma Coexpression of Vimentin and Glial Fibrillary Acidic Protein

A 35-year-old man was operated for a thoracic wall tumor which bulged into the pleural cavity. Histologic examination showed a spindle cell tumor with numerous psammoma bodies and a heavy melanin pigmentation. Electron microscopy revealed me-lanosomes and a continuous basal lamina surrounding all tumor cells, compatible with the diagnosis of a melanotic schwannoma. The tumor cells were S-100 protein-positive, and there was an abundant pericellular laminin-positivity. Practically all tumor cells were vimentin-positive, while cytokeratin, desmin and neurofilaments were absent. Glial fibrillary acidic protein was found in single tumor cells, suggesting the presence of focal glial differentiation in melanotic schwannoma.     

Pilomyxoid astrocytoma of the pineal region: Cytopathological features and differential diagnostic considerations by intraoperative smear preparation

Pilomyxoid astrocytoma (PMA) is a recently identified type of pilocytic astrocytoma (PA) with shorter progression‐free and overall survival, higher rate of recurrence, and higher risk of leptomeningeal spread compared to pilocytic tumors (WHO grade 2 designation). A case is presented here in which intraoperative imprint smears of a pineal region tumor in a 14‐year‐old girl revealed cytologic monomorphism, elongated cells with bland nuclei embedded in a myxoid background. The tumor cells possessed uniformly round nuclei with a smooth nuclear outline, fine granular chromatin, and small nucleoli. Slender cytoplasmic fibrillary processes and angiocentric arrangement were observed but Rosenthal fibers or eosinophilic granular bodies were absent. A cytologic diagnosis of PMA of the pineal region was suggested by intraoperative smear preparation. Histology and immunohistochemical results confirmed the final diagnosis. This report shows that smear preparation can be trustworthy for the intraoperative diagnosis of PMA, helping to determine the appropriate neurosurgical procedure and therapeutic implications. Diagn. Cytopathol. 2015;43:121–124. © 2014 Wiley Periodicals, Inc.     

Hybrid schwannoma/perineurioma of the spinal nerve: Multifocal occurrence,and recurrence as an intraneural perineurioma

A 63‐year‐old Japanese man complained of lower back pain and numbness and was diagnosed as intradural tumors at the T11/12 and L1 level. The thoracic tumor originated from the posterior nerve root, and the lumbar tumor originated from the cauda equina. Five months after surgical resection, the patient developed recurrent tumor consisting of enlargement of multiple caudal nerves. Pathologically, the primary tumors showed a nodular and lobular pattern, including spindle cells in a fascicular, whorl and storiform pattern, with variable cellularity, nuclear palisading and frequent small onion bulb structures. Mild pleomorphism was present, and there were four mitoses per 10 high power fields. Many cells showed immunoreactivity for S‐100 and Sox10. There were also claudin‐1‐positive spindle cells, but no epithelial membrane antigen (EMA)‐positive cells. The cells in onion bulb structures were positive for claudin‐1 and glucose transporter 1 (GLUT‐1). These findings led to a diagnosis of hybrid schwannoma/perineurioma. The features of high cellularity, pleomorphism and a Ki‐67 index over 10% suggested a low‐malignant nature. The recurrent tumor also showed high proliferative activity, as reflected by mitotic figures and a Ki‐67 index of 20%. This is the first case of spinal nerve hybrid schwannoma/perineurioma with low malignant potential and peculiar intraneural perineurioma component.     

Increased production of lipocalin-type prostaglandin D synthase in leptomeningeal cells through contact with astrocytes

Lipocalin-type prostaglandin D synthase (L-PGDS) is dominantly expressed in the leptomeninges surrounding the brain and secreted into the cerebrospinal fluid as β-trace, a major cerebrospinal fluid protein. To examine the interaction between the leptomeninges and the brain parenchyma, we co-cultured rat leptomeningeal cells with cells dissociated from the neonatal rat cortex and found that the production of L-PGDS was remarkably increased after the co-cultivation. A similar increase in L-PGDS production was observed by the co-culturing of the leptomeningeal cells with cells dissociated from astrocyte-rich cultures or with 1321-N1 astrocytoma cells. When a crude membrane fraction prepared from 1321-N1 cells was added to leptomeningeal cell cultures, L-PGDS gene expression was slowly increased up to 48 h after the addition. These results indicate that leptomeningeal cells enhance their L-PGDS production by a slow activation of L-PGDS gene expression through their contact with astrocytes.     

Malignant neurofibroma with glandular differentiation (glandular schwannoma).

A case of malignant shwannoma is reported with unusual elements in an 89-year-old female. A large mass was located in the subcutaneous tissue of the right lateral chest wall and measured 5 cm in the greatest diameter. Histologically the tumor was composed of neurofibroma and malignant schwannoma with glandular differentiation. Neurofibroma characterized by numerous hyaline neural nodules was located in the peripheral portion of the tumor, whereas malignant schwannoma occupied a large part of the central portion of the tumor. The glandular elements observed in some areas of malignant schwannoma consisted of cuboidal and columnar shaped cells and were arranged in tubular or tubulo-medullary fashion in which rosettes or pseudorosettes were found. Mucicarminophilic material was observed, both in the cytoplasm and in the lumen. Seven reported cases of peripheral nerve tumor with glandular differentiation are reviewed briefly.