Collision of a syncytial meningioma and malignant astrocytoma

The coexistence of two or more primary brain tumors is a relatively rare occurrence. We report an 87-year-old woman with a 5-cm cystic-solid, peripherally enhancing, right frontal lobe mass. The woman presented with progressive hemiparesis, difficulty ambulating, and urinary incontinence. Histologic examination of the surgically excised lesion showed geographically distinct areas of syncytial meningioma (World Health Organization grade I) and malignant astrocytoma (World Health Organization grade III). Focally, infiltration of the meningioma by astrocytoma was observed. Differential diagnostic issues are considered and the literature reviewed.     

Periosteal osteoblastoma of the calvaria mimicking a meningioma

While osteoblastoma of the cranial vault is rare, the periosteal form of the tumor is highly unusual, with only one case reported in the English literature. We report on a 24-year-old woman presenting with headache and tinnitus. Magnetic resonance imaging of the brain showed an extra-axial temporal mass with findings that were suggestive of a meningioma. The mass was excised completely, and histological examination revealed a periosteal osteoblastoma arising from the inner surface of the temporal bone and adhering to the dura. The tumor was strongly positive for epithelial membrane antigen, a feature not previously described in osteoblastoma, and one that could lead to a mistaken diagnosis of metaplastic meningioma in a limited sample. A detailed literature review of 40 other reported cases of calvarial osteoblastoma is presented. Apart from being slightly more common in females, calvarial osteoblastoma is similar in all other respects to that arising at conventional skeletal sites. Accurate histological diagnosis of a calvarial osteoblastoma requires adequate sampling of the tumor, including its interface with adjacent structures. Correlation with the radiological findings is crucial for the diagnosis in most cases; however, it is not helpful in differentiating the rare intracranial periosteal variant from a meningioma.     

Meningeal tumors histologically mimicking meningioma

A number of meningeal neoplastic lesions may radiologically and clinically simulate meningioma. In the present paper, we review meningeal non-meningothelial tumors which may also mimic different histotypes of meningioma at the histological examination. Awareness that these lesions exist may facilitate their recognition and correct diagnosis, which is of fundamental importance for prognosis and an appropriate therapeutic approach. Histological and immunohistochemical clues for the differential diagnosis are discussed.     

Intracerebral schwannoma clinically and radiologically mimicking meningioma

A case of intracerebral schwannoma (ICS) occurring in a 33-year-old woman is presented. The patient's history of headache, numbness, tingling and the recent development of weakness of the right upper extremity with right facial droop began during pregnancy. Magnetic resonance imaging (MRI) showed a 4 x 2 x 2 cm heterogeneous, gadolinium-enhanced mass at the left frontoparietal junction, with peritumoral edema and a dural-based attachment. During her pregnancy, the mass increased in size. The surgically resected specimen consisted of lobulated, somewhat gelatinous soft tissue. Microscopically, the tumor demonstrated classic biphasic Antoni type A and B patterns, admixed with degenerative changes. Immunohistochemically, the neoplastic cells were positive for S-100 protein (diffuse and strong), CD34 (primarily in Antoni B areas), glial fibrillary acidic protein (GFAP; weak and diffuse) and calretinin (mainly in Antoni A areas), while none was positive for CD31, estrogen and progesterone receptors, bcl-2, or epithelial membrane antigen (EMA). Ultrastructurally, basal laminae and Luse bodies were identified. The differential diagnosis includes fibrous meningioma, solitary fibrous tumor, and ICS. Twenty-seven cases of ICS were reviewed in which the histological diagnosis was confirmed immunohistochemically or ultrastructually, and the cases were summarized (including the present case). A combined use of immunostains (S-100 protein, EMA, CD34, and maybe calretinin) is of great help in distinguishing ICS from its histological mimickers.     

Dural plasmacytoma mimicking meningioma in a young patient with multiple myeloma

Intracranial involvement in multiple myeloma (MM) is rarely found, especially with dural involvement. There are only a few cases found concerning MM with intracranial involvement. MM usually involves an older group of patients. Cases involving young patients are very rare. The differential diagnosis of a dural plasmacytoma includes meningioma, metastasis, lymphoma and sarcoma of the dura mater. We present a young patient, 33 years old, with MM presenting an intracerebral mass mimicking meningioma on MRI. MM was diagnosed the previous year. The patient presented with headache, balance disturbance and back pain. MRI revealed an occipital extra-axial mass with a dural tail. Histopathological examination after excision showed MM. Published literatures on intracranial involvement of MM are also discussed. Plasmacytoma should be considered in the differential diagnosis of a solitary dural mass, particularly in a patient with MM.     

Solitary intracranial metastasis of follicular carcinoma of the thyroid gland clinically mimicking a meningioma

We describe a rare case of solitary metastasis of follicular carcinoma of the thyroid gland into the petroclival region in a 58-year-old woman. The metastasis was the first and only manifestation of the disease. The histology of the tumor, differential diagnosis and clinical course are discussed. In a few similar cases described so far the tumor was always a well or moderately differentiated follicular carcinoma located in the petroclival region. As in this presentation, these cases also clinically mimic a meningioma. The differential diagnosis includes adenoma of the thyroid gland and thyroid gland dystopia. We demonstrated the primary focus of carcinoma within the thyroid after its detailed examination initiated by our finding. The clinical outcome of such rare cases is usually excellent, much better than in metastases of papillary carcinoma into the brain.     

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.     

Intracranial Rosai-Dorfman disease mimicking isolated meningioma: a case report and review of the literature

Rosai-Dorfman disease is a rare malignant infirmity. Here, we present a case of a 57-year-old man with giddiness and unstable gait, as well as blurred vision in the left eye for four months. Radiologically the diagnosis before surgery was meningioma. The patient received a craniotomy, and the histopathologic diagnosis was Rosai-Dorfman disease. We reviewed the diagnosis, mechanism, and treatment of this disease.     

Cytologic features of pigmented atypical meningioma mimicking melanoma on intraoperative crush preparations

Pigmented tumors rarely arise in the meninges, and when they do, these are mainly melanocytomas or melanomas. We describe the cytologic findings of atypical meningioma with intratumoral hemosiderin pigment mistaken for spindle cell melanoma in a 33‐year‐old male patient during intraoperative consultation. Preoperative radiologic images revealed a cystic meningeal mass with intratumoral hemorrhage. The crush preparation demonstrated cellular smears of syncytial clusters as well as fascicles of large pleomorphic spindle cells with discrete cytoplasmic brown pigment. Detection of cytoplasmic brown pigment and a preponderance of large spindle cells with nuclear pleomorphism led to a diagnosis of spindle cell melanoma on intraoperative cytology. Histopathologic examination displayed high cellularity, nuclear pleomorphism with prominent nucleoli, and foci of spontaneous necrosis. In addition, there were areas showing classic meningotheliomatous meningioma features. Altogether, the histologic findings were consistent with atypical meningioma. The cytoplasmic pigment in the tumor cells was confirmed to be hemosiderin using special stains and immunohistochemistry. To the best of our knowledge, this is the first case report describing cytomorphology of atypical pigmented meningioma. We discuss the differential diagnosis in intraoperative cytology and a possible mechanism related to intratumoral hemosiderin deposition in meningiomas. Diagn. Cytopathol. 2015;43:149–152. © 2014 Wiley Periodicals, Inc.     

Primary clear cell meningioma of the orbit mimicking a metastatic carcinoma: usefulness of immunohistochemistry and cytogenetic analysis

Clear cell meningiomas (CCM) are rare tumors of the nervous system that usually occur in young patients and display high recurrence rates and potentially aggressive behavior. In this report, we describe a primary CCM of the orbit in an 84-year-old man with a previous history of a clear cell carcinoma of the kidney. Histologically, the tumor demonstrated a sheet-like proliferation of clear polygonal cells. Differential diagnosis includes metastasis of clear cell carcinomas. Immunohistochemistry, by showing that tumor cells expressed vimentin, epithelial membrane antigen, and progesterone antigens, and cytogenetic analysis, by identifying a monosomy 22, confirmed the diagnosis of CCM.     

Meningial perineurioma: a benign peripheral nerve sheath tumor in a previously unrecognized central nervous system location, mimicking meningioma

Perineurioma is an uncommon, mostly benign, spindle-cell tumor of peripheral nerve sheath origin with a predilection for the soft tissues. Although increasing awareness points to the sites of involvement by perineurioma possibly being as ubiquitous as those frequented by schwannian tumors, only one intracerebral example has been described to date. We report on a surgically resected perineurioma of the falx cerebri in an 86-year-old woman. Preoperative imaging showed an enhancing extraaxial mass of 6 cm × 5.7 cm × 3.7 cm. Histologically, the tumor consisted of a proliferation of spindle cells interwoven by a lattice of basal lamina. Alongside a prevailing soft tissue perineurioma pattern, sclerosing and reticular areas were seen as well. Tumor cells coexpressed EMA and GLUT-1, and a minority immunoreacted for smooth muscle actin. Pericellular basal lamina was decorated with collagen type IV. No staining for S100 protein was detected. Mitotic activity was virtually absent, and the MIB1 labeling index averaged 2%. Ultrastructural examination revealed abundant pinocytotic vesicles within and conspicuous tight junctions between slender cytoplasmic processes which, in turn, were encased by discontinuous basal lamina. FISH analysis confirmed loss of at least part of one chromosome 22q. This observation calls attention to perineurioma as a novel item in the repertoire of low-grade meningial spindle cell neoplasms, in the differential diagnostic context of which it is apt to being misconstrued as either meningioma, solitary fibrous tumor, or neurofibroma. Confusion with the latter bears the risk of overgrading innocuous features of perineurioma as criteria for malignancy.     

Intracranial benign fibrous histiocytoma mimicking parasagittal meningioma: report of two cases and review of literature

Primary benign fibrous histiocytoma involving the central nervous system is an exceedingly rare tumor with most cases originating from the dura or parenchymal tissue. Diagnosis of primary benign fibrous histiocytoma is difficult due to its confusing histopathological characteristics. Two cases of primary intracranial benign fibrous histiocytoma mimicking parasagittal meningioma are presented in this report. Both tumors were gross totally resected and the patients showed no evidence of recurrence at follow-up of 12 months. The clinical features and prognosis of this rare tumor that were reported previously in the literature were also reviewed. Histopathological examination coupled with immunohistochemical staining is proved to be the convincing diagnostic method for the primary benign fibrous histiocytoma. Surgical resection is the recommendation for the therapy of the tumor.     

毛细胞黏液样星形细胞瘤和毛细胞星形细胞瘤的临床病理分析

毛细胞黏液样星形细胞瘤(PMA)是1999年Tihan等~([1])提出的一个肿瘤分类,是毛细胞星形细胞瘤(PA)的一个特殊亚型,两者在临床和病理学上有着不同之处,国内见陈莲等~([2])报道过4例,复发并演变为PMA者目前尚少见报道.我们对1例复发的PMA和12例PA进行回顾性分析,以进一步探讨两者的关系.