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Potpourri of Rare Central Nervous System Tumors



Article By



Kavita Mardi




Five interesting and rare central nervous system tumors are presented. These include, Pleomorphic Xanthoastrocytoma with Anaplastic features, Rhabdoid Meningioma, Calvarial Meningioma, Eosinophilic Granuloma of Dural origin, Primary Paraganglioma of Craniospinal Axis. These are in the domain of Oncologic Surgical Neuropathology.



Oncologic surgical neuropathology is a dynamic field. The unparalleled complexity of the central nervous system (CNS) is mirrored by the ever-increasing diversity of recognized neoplastic entities that can afflict the organ. In many instances,   the   emergence   of   ‘‘new’’   entities are a reflection of our increasing ability to sub divide large categories of tumors into more refined, clinically and  biologically meaningful, subtypes for purposes of patient prognosis and/ or treatment stratification.


We herein describe five interesting case reports of CNS tumors


Case 1  :  A  55-year-old  male  presented  with weakness  and  numbness   of  right  upper  and lower limbs since 3 months.  Patient  had  difficulty walking as well as difficulty speaking. In addition, the   patient   complained   of  headache since nine months.  There was a disturbance  of vision in both eyes. Sensations were reduced in the lower side of the maxillary and mandibular region and there was difficulty in hearing in the right ear. Pain sensation was reduced on the right side. Tone and bulk were reduced in right upper and lower limbs. Clinical diagnosis of metastatic tumor in the brain was rendered. Patient underwent a computed tomography (CT) scan and possibilities of multicentric glioblastoma multiforme and metastatic deposits in brain were suspected. Patient underwent right frontal craniotomy with excisional biopsy  of  both  lesions in  the  right cerebral hemispheres. Preoperatively the tumor was firm and moderately vascular. Microscopic examination revealed sheets of pleomorphic astrocytes  showing  focal fascicular arrangement and  numerous   tumor   giant  cells. The  tumor cells showed  enlarged,  hyperchromatic  bizarre nuclei with prominent  nucleoli and  occasional intranuclear  inclusions. The cytoplasm of these tumor  cells varied from eosinophilic to hyaline to foamy. Abundant  Periodic Acid Schiff (PAS) positive granular eosinophilic bodies were seen. Focal perivascular patchy lymphocytic infiltrate was seen. There was dense reticulin staining around single or grouped tumor cells. There were extensive areas of tumor  necrosis and moderate number of mitotic figures of 5 to 6/10 high power field (HPF). The tumor  cells were immunohistochemically positive for  glial fibrillary acidic protein (GFAP), focally (some cells) positive for synaptophysin and negative for vimentin. Ki-67 index was about  5%. Histological diagnosis of “pleomorphic xanthoastrocytoma with anaplastic features (PXA)” was rendered.


Synchronous, multicentric pleomorphic xanthoastrocytoma    with    anaplastic    features as seen in  the  present  case are extremely rare neoplasms[1,2]. 9% to 20% of PXA astrocytoma to undergo  malignant  transformation[2]  and  some of them  exhibit anaplastic features at  the  first presentation. The World Health Organization (WHO) recommends the designation “PXA with anaplastic features” to denote PXA featuring high mitotic activity (3-5 mitoses per 10 HPF) with or without accompanying necrosis. The designations “anaplastic PXA” and “PXA grade III or IV” are currently not recommended by WHO.


Case 2 :  A 28-year-old male presented  with a history  of progressive weakness and  decreased sensation in both lower limbs. He also complained of weakness and numbness up to the nipple. There was no bladder involvement. On examination,  there was Grade I to II weakness in both lower limbs and sensory loss (touch, pain, temperature)  below T3 and T4. Magnetic resonance imaging (MRI) revealed an intradural extramedullary tumor at C7-T1 level. Laminectomy C7-T1 was done with complete excision of the intradural,  extramedullary,  well circumscribed, firm, vascular tumor  arising from  dura  C7-T1 and compressing the cord significantly. On microscopic  examination  of  the  resected  tumor, most of the tumor  cells exhibited typical rhabdoid morphology with large vesicular often eccentrically located nuclei with distinct nucleoli and abundant cytoplasm containing eosinophilic hyaline inclusions. Numerous psammoma bodies were also seen. Classical meningothelial features with focal whorl formation were scarce and seen only in a few foci. Immunohistochemically, these rhabdoid  cells showed epithelial membrane  antigen (EMA) as well as vimentin positivity. Final diagnosis of “rhabdoid meningioma lacking malignant features”was given.


In 2000, rhabdoid meningiomas were included in the revised WHO classification of tumors of the CNS as a subtype of meningiomas with increased risk of recurrence and more aggressive growth, corresponding to WHO Grade III. Meningiomas with focal rhabdoid  differentiation  are considered WHO  Grade I. Rhabdoid features should constitute over 50% of tumor to classify a meningioma as a “rhabdoid meningioma”[3]  (as per WHO grade III classification of tumors).


Case 3 :  A 60-year-old female presented  with persistent left sided headaches since 6 months. Headaches were a dull ache type, centered over the left parietal region. Radiographs of the skull revealed a well-defined area of osteolysisin the left frontoparietal region. CT scan showed an enplaque enhancing tumor extending over the left frontoparietal  convexity. The calvarial bone was thickened all along the length of the tumor. The underlying dura and brain were normal. The patient underwent a left frontoparietal craniotomy. The  bone  was thick  and  extensively vascular. The involved calvarium was resected widely. The extradural  meningioma  was diffuse and  carpet like. It was soft and greyish and only moderately vascular. This mass was removed along with the  involved markedly  thick  dura. Microscopic examination revealed sheets and tight whorls of meningothelial cells with round to oval vesicular nuclei, inconspicuous nucleoli and eosinophilic cytoplasm with indistinct  cytoplasmic borders. The tumor cells were permeating in between the existing bony trabeculae of calvarial bone. Occasional cells showed intranuclear  pseudoinclusions. There was no mitotic activity or any foci of necrosis. There were large number  of psammoma bodies. The case was diagnosed as “calvarial meningioma”.


Extracranial meningiomas are rare and account for 1%–2% of all meningiomas[4]. Calvarial meningiomas are more prone  to develop malignant changes  (11%) as  compared  with  intracranial meningiomas (2%)[5].


Case 4 : An 11-year-old female child presented to the neurosurgery outpatient  department  with a swelling in the right frontoparietal region. An osteolytic lesion was detected on X-ray in the right frontal  area. MRI demonstrated  a well-defined enhancing mass measuring 3.5x3x2.5 cms with a wide dural attachment and an expansile lytic lesion in the frontal bone. A chest X-ray and other radiological examinations showed no other osseous or soft tissue lesions. The patient underwent right parietal extended craniotomy. Intraoperatively there  was a soft fleshy mass originating from the dura mater in the right parietal region and protruding  out of the bony defect. The lesion  was completely removed  together  with  a margin of grossly uninvolved dura and bone. The excised mass was sent to us for histopathological examination. Microscopically, there were sheets and  clusters of Langerhans’ cells with typically grooved  and  irregularly  contorted  nuclei  with a  thin  nuclear  membrane,  delicate  chromatin and inconspicuous nucleoli. The cytoplasm was abundant and lightly eosinophilic. Abundant eosinophils and frequent multinucleated giant cells were also present. The Langerhans cells were immunoreactive for CD-1a. The case was diagnosed as “eosinophilic granuloma of dural origin”.


In current  literature review, only a few cases of eosinophilic granuloma originating from dura mater  were found[6].  An  inflammatory  process of the dural membrane with migration of Langerhans’ cells could be the physiopathological basis for the formation of intradural eosinophilic granuloma[6].


Case 5  :  A 42-year-old female presented  with pain and  burning  sensation in the lower back. Pain was moderate and intermittent  initially and became continuous  in  the  last 6 months.  Pain was radiating to the gluteal region and increased on coughing and on taking a deep breath. There was no history of urinary or bowel problems. On clinical examination, motor  and sensory systems were within normal limits. All the reflexes were present. The spine showed no deformity. X-ray of the lumbar spine was also normal. However MRI showed an intradural, extra medullary, well- defined mass at the L4-L5 level. Possibilities of neurofibroma and ependymoma were suggested. Laminectomy of L3- S1 with near total excision of the tumor was conducted and a 3×3 cm multi-

lobular, pinkish, friable mass arising from cauda equine  was excised. On  microscopic examination, the tumor  was partially encapsulated and comprised of nests and broad anastomosing trabeculae of round to polygonal tumor cells, separated by delicate, fibrovascular septa (zellballen pattern).  These tumor  cells showed moderately abundant  eosinophilic cytoplasm, central round to  oval nuclei  with  finely stippled  chromatin, occasional nucleoli and intranuclear  inclusions. The tumor cells were positive for chromogranin and synaptophysin. A diagnosis of “paraganglioma of caudal equine” was made.


Primary   paragangliomas  of  craniospinal   axis are predominantly  found  in the intradural,  extramedullary  compartment  at  the  level of  the cauda equina[7]. Current  WHO  classification of CNS tumors  classifies paragangliomas as grade I tumors. Complete surgical resection is considered curative and subtotal resection often leads to recurrence. Total excision is often very difficult owing to the tendency of these neoplasms to infiltrate the cauda equina roots. Less than 1% are locally aggressive[8].


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