Spinal Hemangiopericytoma: a Rare Ocurrence.
Antônio Santos de Araújo Júnior, MD1; Arnaldo Salvestrini Jr, MD1; Pedro
Alberto Arlant, MD, PhD1; Orlando Parisi, MD2; Mirella Martins Fazzito, MD3;
Conrado Furtado de Albuquerque Cavalcanti, MD4; Hae Won Lee, MD4;
Ricardo Antenor de Souza e Souza, MD5; Luiz Heraldo Arouche da Câmara
Lopes, MD, PhD5.
1.
Neurosurgeon from Sírio Libanês Hospital, São Paulo, Brazil
2.
Head and Neck Surgeon from Sírio Libanês Hospital, São Paulo, Brazil
3.
Neurologist from Sírio Libanês Hospital, São Paulo, Brazil
4.
Radiologist from Sírio Libanês Hospital, São Paulo, Brazil
5.
Neuropathologist from Sírio Libanês Hospital, São Paulo, Brazil
Antônio Santos de Araújo Júnior
Correspondence Address:
Rua Peixoto Gomide, 515, cj 96, Cerqueira César, São Paulo, São Paulo, Brazil. CEP 01409-001.
Phone/Fax: 05511-32890411 Cel: 05511-84567404
Email: dr.antonioaraujojr@gmail.com; Website: araujoefazzito.com.br
Abstract
Introduction:
Most
hemangiopericytomas
(HPC)
are
located
in
the
musculoskeletal system and the skin, while the location in the central nervous system
(CNS) is rare.
Objective and Methods: We describe a patient suffering from a spinal
extradural huge HPC, with marked spinal cord compression, extending from C6 to T3
level, who was elected to surgery.
Results: Patient was submitted to surgery, via a posterior approach,
indentifying a huge red-brown firm mass, highly vascular, that was softly dissected from
surrounding tissues. Total gross removal was accomplished, with “in-block” resection,
preserving neurological function, as shown by somatosensitive evoked potential.
Histopathological examination and immunohistochemistry essay were performed
confirming the diagnosis of Hemangiopericytoma.
Conclusion: Spinal HPCs respond to approximately 8% of all HPC, tend to
occur isolated and attached to spinal dura-mater, and usually present a good surgical
cleavage between the tumor and the dura.
Key-words: CNS tumor, spinal tumor, hemangiopericytoma.
Introduction
Most hemangiopericytomas (HPC) are located in the musculoskeletal
system and the skin, while the location in the central nervous system (CNS) is
rare. The latter represents 2 to 4% in large series of meningeal tumors, thus
accounting for less than 1% of all CNS tumors. In the CNS, tumors with a
hemangiopericytomatous
histopathological
pattern
can
be
either
hemangiopericytomas, or solitary fibrous tumors 1. Another differential diagnosis
of CNS tumors with hemangiopericytoma-like pathological characteristics,
originating especially in the lumbar spine, is the synovial sarcoma 2.
Solitary fibrous tumour (SFT) is a rare soft tissue tumour of uncertain
histogenesis and unpredictable biological behavior, which was first described in
the pleura and subsequently in many extra-pleural locations 3. Solitary fibrous
tumours (SFT) of the central nervous system are rare neoplasms that usually
present as dura-based masses and clinically resemble meningiomas.
Histologically, they can be similar to haemangiopericytoma or fibrous
meningioma 4.
A synovial sarcoma is a mesenchymal spindle cell tumor that displays
variable epithelial differentiation including glandular formation. It is unrelated to
a synovium. More than 80% of these lesions arise in the deep soft tissue of the
extremities. The tumor frequently arises adjacent to joints or tendon sheaths,
especially in the lumbar spine 2.
CNS hemangiopericytomas (HPC), by definition, are highly cellular and
vascularized mesenchymal tumour exhibiting a characteristic monotonous lowpower appearance and a well-developed, variably thick-walled, branching
“staghorn” vasculature; almost always attached to the dura and having a high
tendency to locally recur and to metastasize outside the CNS 5.
Thirty years-ago HPC were still classified as variant of ‘angioblastic
meningiomas’, but it has now been long accepted that hemangiopericytoma and
meningioma are different entities 5. In large series, the ratios of meningeal
hemangiopericytoma to meningioma were about 1:40 6.
Epidemiological
differences
between
hemangiopericytomas
and
meningiomas include: HPC tend to occur at a younger age than meningiomas;
HPC are slightly more often in men than in women.
Meningiomas tend to occur eventually in every location of the neuroaxis,
instead of HPC that occur slightly more often in the occipital region, around the
confluence of sinuses, and attached to venous sinuses 5. By its time, HPC are
almost invariably solitary, with approximately 8% located attached to spinal dura
6.
On radiographic films, HPC appear as a well-demarcated, lytic lesion of
adjacent bone, without hyperostosis, a typical feature of meningiomas. Unlike
meningiomas, HPC typically lack calcification 5.
On macroscopic examination, meningeal HPC is a solid, welldemarcated tumor, with a tendency to bleed during removal, sometimes
profusely
5.
The tumor is usually globoid, slightly lobulated, with firm
consistency, grayish to red-brown colored.
On histopathology, HPC appears as monomorphous tumors composed
of closed packed, randomly oriented tumor cells, with little intervening fibrosis
and marked extracellular matrix. A rich network of reticulin fibers, typically
investing individual cells, is one of the most characteristic features of this tumor
5.
HPCs are very highly vascular tumors, with numerous slit-like vascular
channels lined by flattened endothelial cells and branching vascular spaces, the
“staghorn sinusoids”
5.
Necroses are uncommon. Calcification, including
psammoma bodies, is not seen. They may destroy adjacent bone, without
hyperostotic reaction, but rarely invade adjacent brain parenchyma or the spinal
cord 5.
On immunohistochemistry essay, HPC cells are diffusely immunoreactive
for vimentin (85% of cases), factor XIIIa (80-100%) in individual scattered cells,
Leu-7 (70%) and CD34 (33-100%) in a patchy pattern. Diffuse CD34 pattern
diagnoses
solitary
fibrous
tumor.
Meanwhile,
strong
and
diffuse
immunoreactivity for epithelial membrane antigen, claudin-1, desmin, smooth
muscle actin, endothelial antigens (CD31) and progesterone receptor diagnose
meningioma. Immunohistochemistry differentiation of HPC from solitary fibrous
tumor and meningioma is usually feasible and possible.
Spinal hemangiopericytomas
Spinal HPCs respond to approximately 8% of all HPC, tend to occur
isolated and attached to spinal dura-mater, and usually present a good surgical
cleavage between the tumor and the dura.
Spinal HPCs are very rare and mostly involve the extradural bony
structures. Primary intradural HPC has only been reported in 10 cases, all of
which occurred in the extramedullary region 7.
We describe a patient suffering from a spinal extradural huge HPC, with
marked spinal cord compression, extending from C6 to T3 level, who was
elected to surgery.
Case report
We describe a 66-year-old male patient harboring a chronic onset of right
leg distal paresis, and instable gait. On neurological examination, he presented
with right leg monoparesis (strength grade 4 distal, 5 proximal), intact pain and
light touch sensitivity, loss of unconscious proprioception, with deep tendon
patellar hyperreflexia, and abnormal Romberg´s test with sensory ataxia.
The patient was promptly submitted to cervicothoracic MRI, showing a
huge paravertebral mass, ranging from C6 to T3 level, with homogeneous
Gadolinium enhancement, and marked spinal cord compression at T1 level
(Figure 1-2).
A
B
C
Figure 1. Sagital cervicothoracic T2-weighted (A and B) and post-contrast T2weighted (C) MRI. (A) Paravertebral cervico thoracic mass, with lobulated
appearance; (B) At T1 level, tumoral spinal cord compression without dural
invasion, intratumoral heterogeneous signal; (C) Post-Gadolinium, homogeneous
tumoral enhancement.
A
B
C
Figure 2. Axial cervicothoracic T2-weighted MRI (A and B) and post-contrast T1weighted MRI (C). (A) Paravertebral mass with lytic lesion from right T1 lamina and
spinous process, dislocating the spinal cord to anterior left position; (B) At T1 level,
marked spinal cord compression by heterogeneous signal lesion; (C) PostGadolinium, homogeneous tumoral enhancement.
In the same day, patient was prepared to surgery, and to general
anesthesia,
with
intraoperative
somatosensitive
evoked
potential
and
intermittent pneumatic leg compression. Patient was turned to prone position.
Patient was then submitted to surgery, via a posterior approach,
indentifying a huge red-brown firm mass, highly vascular, with profuse bleeding
even through small cuts. Therefore, surgical strategy was, every moment, in a
patient fashion, to contour the lesion, without cutting it. At last, T1 laminectomy
was performed in order to dissect the tumor from the dura-mater, with clear
cleavage plane.
Total gross removal was accomplished, with “in-block” resection (Figure
3), preserving adjacent tissues and the neurological function, as shown by
somatosensitive
evoked
potential.
Histopathological
examination
and
immunohistochemistry essay were performed confirming the diagnosis of HPC
(Figure 4-5).
Postoperatively,
patient
was
symptom-free,
with
accomplishing normal daily activities within 2 weeks.
Figure 3. Total gross ‘in block’ resection, measuring almost 10 cm.
normal
gait,
A
B
Figure 4. Hematoxylin and eosin (HE) stain histopathology. (A) 40x magnification,
monomorphous tumor composed of closed packed, randomly oriented tumor cells;
(B) 100x magnification, highly cellular tumor with staghorn-type vessels, little
intervening fibrosis and marked extracellular matrix, and with lipomatous
deposition.
A
B
C
Figure 5. (A) HE stain, 400x, closed packed monomorphous cells with lipomatous
deposition; (B) Immunohistochemistry essay, 400x, patchy pattern
immunoreactivity for CD34; (C) Immunoreactivity for CD31, 400x, patchy pattern.
Prognosis
HPCs tend to grow faster than anaplastic meningiomas, instead the
same median Ki-67 labelling index of 5% (1.2-39%)8. Therefore they recur more
frequently and in short time intervals, with median time of recurrence of 40 to 70
months.
The local recurrence occurs in approximately 85 to 91% of cases after 15
years
6,9.
Radiotherapy appears to postpone recurrence, in one series, 9 of 17
irradiated HPCs recurred with a median of 58 months, but 13 of 15 nonirradiated tumors recurred with a median of only 29 months 6.
Eventually meningeal HPCs can metastasize to the bones, lungs and
liver. Overall, in a series of 28 patients harboring intracranial HPCs, the
probability of tumor-related death was 61% at 15 years 9, and the survival after
the diagnosis of metastases was only 2 years 9.
Nonetheless, all clinical series about HPCs report recurrences rates,
predictive and prognostic factors of intracranial tumors. Up to now there is no
information over this issue exclusively about spinal HPCs.
Conclusion
Spinal HPCs respond to approximately 8% of all HPC. They tend to
occur isolated and attached to spinal dura-mater, and usually present a good
surgical cleavage between the tumor and the dura, and between the tumor and
the surrounding tissues, allowing almost always total resection.
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