Kalcifikující pseudoneoplazma nervového systému – tři kazuistiky
Kalcifikující pseudoneoplazmata nervového systému (CAPNONA) jsou vzácné léze, které byly popsány v intra- i extraaxiálních lokalizacích intrakraniálně a v extraaxiálních lokalizacích ve spinální oblasti. Charakteriským znakem na magnetické rezonanci je centrální výpadek signálu na T1 a T2 vážených obrazech s postkontrastním zvýrazněním po aplikaci kontrastní látky. Nicméně histologická skladba může být různorodá, což se v zobrazení může odrazit. Předkládáme tři kazuistiky CAPNONA, které byly detekovány pomocí MR a potvrzeny histologicky. Kazuistiky jsou doplněny rozsáhlým přehledem literatury s MR charakteristikami těchto lézí, jak byly dosud popsány.
A. M. Rulseh 1,2; J. Keller 1,3; J. Klener 4; J. Šroubek 4; M. Syrůček 5; I. Zemanová 5; V. Dbalý 4; J. Vymazal 1,6
Department of Radiology, Na Homolce Hospital, Prague, Czech Republic
1; Department of Radiology, First Faculty of Medicine, Charles University, Prague, Czech Republic
2; Department of Neurology, Third Faculty of Medicine, Charles University, Prague, Czech Republic
3; Department of Neurosurgery, Na Homolce Hospital, Prague, Czech Republic
4; Department of Pathology, Na Homolce Hospital, Prague, Czech Republic
5; Department of Neurology, First Faculty of Medicine, Charles University, Prague, Czech Republic
Cesk Slov Neurol N 2011; 74/107(5): 584-589
Calcifying pseudoneoplasms of the neural axis (CAPNONA) are rare lesions that have been reported in both intra/extra-axial locations intracranially, and in extra-axial locations in the spinal region. Central loss of signal on T1/T2-weighted images with enhancement following contrast administration is most commonly observed on magnetic resonance imaging, however, the histopathological composition of CAPNONA is diverse which may be reflected in the imaging findings. We present three cases of CAPNONA detected by MRI and confirmed by histological evaluation, and the largest review of the MRI characteristics of these lesions to date.
pseudoneoplasms of the neural axis (CAPNONA), or fibro-osseous
lesions as they are alternatively known, are rare, tumor-like lesions
that have been reported to occur in both intra-axial (IA) and
extra-axial (EA) locations intracranially, and in EA locations
in the spinal region. Due to their rarity, CAPNONA are seldom
considered in the differential diagnosis of atypical brain or
spinal lesions. These lesions carry an excellent prognosis and are
generally curable by surgical resection. We present three cases of
detected with magnetic resonance imaging (MRI) and confirmed by
male with a three-year history of headache suffered a skull
fracture at the age of eleven in the right parietal region following
a blow to the head with a sharp metal object. Current
neurological examination did not reveal any abnormalities. MRI at
1.5T showed a wedge-shaped lesion in the right angular region
with increased signal intensity and central hypointense areas on
proton-density- (PD) and T2-weighted images (Fig. 1a). The
wedge-shaped region had significantly decreased signal intensity on
T1-weighted images, suggestive of a pseudocystic lesion.
Internal nodular enhancement was observed after contrast agent
administration (Fig. 1b). Due to the ambiguous character of the
clinically symptomatic lesion, microsurgery with navigation was
recommended. During the surgery a bony fragment approximately 8
× 10 × 20 mm was
observed as the plate of the skull was lifted off. The fragment was
adherent to and extended 20 mm into the brain parenchyma. Gross and
intraoperative microscopic inspection of the MRI-enhancing nodule
revealed a fibrous stroma filled with numerous small
calcifications. Histological examination showed a chondromyxoid
matrix in a nodular pattern, calcification and osseous
metaplasia, scattered psammoma bodies, palisading spindle cells,
foreign-body-like reaction with giant cells and a fibrous stroma
(Fig. 2). The postoperative course of the patient was
uneventful. The patient reported the cessation of his headaches
and MRI six months after surgery demonstrated total removal of the
lesion (Fig. 1c).
female presented with recurrent pain in the lumbar region with
radiation to both legs along the dorsal aspect. She had undergone
surgery of the lumbar spine two years previously for isthmic
spondylolisthesis and a herniated disc at L5/S1. MRI at 1.5T
showed a small nodular extradural lesion at the level of L3. The
lesion was hypointense on T1-, T2- and PD-weighted images (Fig. 3).
No contrast agent was administered. During the microsurgery a small,
calcified nodule approximately 5 mm in diameter was removed. The
nodule was attached to one of the nerve roots accompanied
by small tortuous vessels supplying a vascularized fibrous
stroma. Histological examination revealed a calcified lesion
consisting of primitive bone trabeculae and islets of choroid tissue
in a moderately cellular matrix, scattered psammoma bodies and
a fibrous stroma. The pathologist confirmed the diagnosis of
The postoperative course of the patient was uneventful. MRI ten
months after the surgery showed no evidence of recurrence.
male was referred due to refractory epilepsy. At ten years of age he
suffered an episode of serous meningitis and developed epilepsy two
years later. At the age of fifteen a pial AVM in the left
frontal region was diagnosed and resected. Following the surgery the
patient has been seizure-free for four years, after which time the
seizures recurred. CT and MRI examination revealed a calcified
lesion in the post-resection area with surrounding gliosis (Fig. 4).
MRI was acquired at 1.5T and revealed a hypointense lesion on
T1-, T2- and PD-weighted images. No contrast agent was administered.
During the surgery a large area of gliosis was identified and
resected. The resected area included calcified tissue measuring
approximately 7 × 6 × 2 mm, in contact with the frontal horn of the
left lateral ventricle. Histological examination of the calcified
tissue showed palisading spindle to epithelioid cells, calcification
and osseous metaplasia with primarily adipose bone marrow, and
a fibrous stroma. The pathologist confirmed the diagnosis of
CAPNONA. The patient had two seizures during
the first week following the surgery, and since that time (11/2009)
described by Rhodes and Davis in 1978 , only 45 cases of CAPNONA
have been reported [1–18]. CAPNONA have been reported more in males
than females (1.5:1) and in ages ranging from 6–83 years (27 male,
18 female; mean age at diagnosis 47.4 years, SD 17 years) (Table 1).
characteristics of CAPNONA are diverse. Aiken et al.  summarized
the typical findings as the variable appearance of 1. a typical
chondromyxoid matrix in a nodular pattern; 2. palisading spindle
to epithelioid cells; 3. variable amounts of fibrous stroma; 4.
calcification, osseous metaplasia, and scattered psammoma bodies; 5.
and foreign-body reaction with giant cells. Only one of our cases
demonstrated all five findings. Calcification, osseous metaplasia,
scattered psammoma bodies, and a variable amount of fibrous
stroma were seen in all three of our cases.
MRI findings in CAPNONA have been
previously reported [2,4,7–15] and may be summarized as 1. central
low signal intensity on T1/T2/PD-weighted images consistent with
calcification, and 2. variable post-contrast enhancement, most often
seen as peripheral rim enhancement. There may be a single focus
or multiple foci of low signal intensity reflecting the heterogeneous
nature of calcification reported in these lesions.
Some exceptions to these typical
findings have been reported. Moser et al.  reported central
T1 isointensity with a margin of slightly increased signal, and
central T2 hyperintensity. At surgery the lesion was found to be
fluid-filled. Park et al.  reported central isointensity on
T1/T2-weighted images; the pathology report indicated that the mass
was semi-solid and contained only scattered calcification.
Montibeller et al.  also presented a case with central T1
isointensity; the lesion was shown to be of low cellularity and only
partially calcified. All three of the cases we present showed central
hypointensity in all imaging sequences.
When a contrast agent has
been administered, peripheral rim enhancement is most often reported
and reflects the presence of a well-developed fibro-vascular
stroma [2,8,11,13,14]. Internal enhancement has been reported to
occur as homogeneous , heterogeneous , or linear , and
lesions showing no enhancement have been reported as well [2,7,15].
A contrast agent was only administered in one of our patients
and showed a nodular pattern of internal enhancement.
The differential diagnosis of
calcified intra- and extra-axial lesions is broad, but can be
significantly narrowed by reviewing the medical history of the
patient and by careful observation of the location and imaging
characteristics of the lesion. To the best of our knowledge, CAPNONA
have never been reported to occur within the spinal cord. It would
appear from the limited amount of data available that CAPNONA
occur in three spaces (IA-Intracranial, EA-Intracranial, EA-Spinal),
and within each of these three spaces with approximately equal
frequency (Table 1).
Primary neoplasms such as
oligodendrogliomas, choroid plexus papillomas, ependymomas,
astrocytomas, meningiomas, and craniopharyngiomas may all
present as calcified intracranial masses  and should be
included in the differential diagnosis. Other calcifying intracranial
processes may also be considered such as chronic hematomas, vascular
malformations, and tuberculoma. In the spine, the differential
diagnosis of a calcified mass should include herniation of
calcified disc material, calcified synovial cyst and psammomatous
meningioma, followed by less frequently calcifying processes such as
epidural abscess, chronic hematoma and tuberculoma.
CAPNONA are often considered to
be a reactive, metaplastic response to injury [1,3,12,13,16].
A history of trauma or surgery was only reported in five cases
previously, being positive in three [2,6,15] and negative in two
[1,18]. All three of our patients had a history of previous
trauma (case 1) or surgery (cases 2 & 3), and in two of these
cases this directly impacted the region where CAPNONA later
manifested. In one of our cases the previous surgery was at the
level of L5/S1 and CAPNONA
later manifested at the level of L3. Thus, our cases lend further
support to a reactive hypothesis.
In conclusion, CAPNONA are rare,
benign lesions that have been reported in IA and EA locations
intracranially and in EA locations in the spinal region. The
histopathological composition of these lesions is diverse, which may
be reflected in the imaging findings. Finally, considering the
history of trauma or surgery in the cases presented here and in those
reported previously in the literature, it would appear that in at
least some cases CAPNONA
are a reactive, metaplastic response
work was supported by grant NS 9654-4 from the Ministry of Health of
the Czech Republic and by Ministry of Education Research Programs MSM
0021620849 and MSM 0021620816.
Josef Vymazal, M.D., D.Sc. Na
Homolce Hospital Roentgenova
Prague 5 e-mail:
for review: 31. 12. 2010 Accepted
for print: 4. 4. 2011
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