Article

CT-guided, COBRA-FISH-assisted diagnosis of well-differentiated liposarcoma (inflammatory subtype) of the retroperitoneum

Molecular Cell Biology Group , Leiden University, Leyden, South Holland, Netherlands
Histopathology (Impact Factor: 3.45). 10/2007; 51(3):422-6. DOI: 10.1111/j.1365-2559.2007.02782.x
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Available from: Karoly Szuhai
In contrast to the surgical specimens, morphological
transition from the pheochromocytoma component to
the MPNST component was observed in the autopsy
material. This observation, coupled with immuno-
histochemistry for chromogranin in the pheochromo-
cytoma and S100 protein in the MPNST, indicated that
the MPNST was a derivative of the former. It has long
been speculated that sustentacular cells are the origin
of the MPNST component in composite pheochromo-
cytoma, because sustentacular cells are a constituent
of pheochromocytoma.
2–4
Sustentaculoma, a tumour
comprising exclusively sustentacular cells, has been
recently reported.
6
Thus, our observation in the
current case provides further crucial evidence that
sustentacular cells in the pheochromocytoma compo-
nent are the origin of the MPNST in composite
pheochromocytoma.
E S Ch’ng
Y Hoshida
N Iizuka
E Morii
J-I Ikeda
A Yamamoto
Y Tomita
H Hanasaki
1
T Katsuya
1
K Maeda
1
M Ohishi
1
H Rakugi
1
T Ogihara
1
K Aozasa
Departments of Pathology and
1
Geriatric Medicine, Osaka
University Graduat e School of Medicine, Suita, Osaka,
1. Min KW, Clemens A, Bell J, Dick H. MPNST and pheochromo-
cytoma. A composite tumor of the adrenal. Arch. Pathol. Lab.
Med. 1988; 112; 266–270.
2. Miettinen M, Saari A. Pheochromocytoma combined with
malignant schwannoma: unusual neoplasm of the adrenal
medulla. Ultrastruct. Pathol. 1988; 12; 513–27.
3. Sakaguchi N, Sano K, Ito M et al. A case of von Recklinghausen’s
disease with bilateral pheochromocytoma—MPNSTs of the
adrenal and gastrointestinal autonomic nerve tumors. Am. J.
Surg. Pathol. 1996; 2; 889–897.
4. Thompson LD. Pheochromocytoma of the Adrenal gland Scaled
Score (PASS) to separate benign from malignant neoplasms: a
clinicopathologic and immunophenotypic study of 100 cases.
Am. J. Surg. Pathol. 2002; 26; 551–566.
5. Unger P, Hoffman K, Pertsemlidis D et al. S100 protein-positive
sustentacular cells in malignant and locally aggressive adrenal
pheochromocytomas. Arch. Pathol. Lab. Med. 1991; 115; 484–
487.
6. Lau SK, Romansky SG, Weiss LM. Sustentaculoma: report of a
case of a distinctive neoplasm of the adrenal medulla. Am. J. Surg.
Pathol. 2006; 30; 268–73.
CT-guided, COBRA-FISH-assisted diagnosis
of well-differentiated liposarcoma
(inflammatory subtype) of the
retroperitoneum
DOI: 10.1111/j.1365-2559.2007.02782.x
Sir: Of all primary sarcomas, 15% arise in the
retroperitoneum, which consequently represents the
second most common site for malignant soft tissue
tumours after the thigh.
1
Liposarcomas probably
account for 25–35% of all soft tissue tumours at this
site and are subclassified as well-differentiated, dedif-
ferentiated, myxoid and pleomorphic liposarcoma.
2
Well-differentiated liposarcoma can be further sub-
divided into adipocytic, sclerosing, inflammatory and
spindle cell subtypes. These subtypes show consider-
able morphological overlap, especially in the retro-
peritoneum, making the differential diagnosis wide
and problematic.
3
Diagnosis of retroperitoneal tu-
mours mostly relies on radiology and histology.
Computed tomography (CT) scanning and magnetic
resonance imaging (MRI) are the radiological proce-
dures of choice in determining the extent of local,
regional and distant tumour spread. They also distin-
guish between fatty and non-fatty areas and, in the
case of CT, serve as essential guides for adequate
biopsy.
4
Needle biopsies of retroperitoneal tumours,
however, risk tumour spill of the biopsy track.
Moreover, since the amount of tissue available by
needle biopsy is often sparse, histological diagnosis
might be very difficult. Therefore, an additional
immunohistochemical and or molecular cytogenetic
marker might serve as a valuable tool for confirming
the preoperative diagnosis of retroperitoneal tumours
in Trucut biopsy specimens.
A 64-year-old healthy male with no relevant medical
history presented with a 120-mm painless swelling on
palpation of his right abdominal side. Careful clinical
examination and laboratory data showed no further
abnormalities. CT and MRI scans of the abdomen
showed a mass containing fatty components in the
posterior abdominal wall extending towards the retro-
peritoneum. After contrast enhancement, the non-fatty
components markedly enhanced, as did the right psoas
muscle, the retroduodenal and the perirenal lesions
(Figure 1). CT-guided Trucut biopsy specimens showed
a proliferation of fibroblast-like cells with slight nuclear
atypia (Figure 2A) infiltrating the surrounding striated
muscle. Mitotic figures were not encountered within
the biopsy specimen. Adipocytes were present but no
obvious variation in diameter of the vacuoles or any
nuclear atypia were seen. Dense lymphocytic infiltrates
422 Correspondence
2007 The Authors. Journal compilation 2007 Blackwell Publishing Ltd, Histopathology, 51, 405–432.
Page 1
were present at the edge of the sample. Taking into
account the localization of the tumour and the mesen-
chymal aspect of the tumour cells, so-called well-
differentiated liposarcoma (inflammatory subtype),
inflammatory myofibroblastic tumour, atypical neuro-
fibroma, low-grade fibromyxoid tumour and leiomy-
oma of deep soft tissue were considered based on
the morphology alone. Immunohistochemistry showed
focal cytoplasmic immunoreactivity of the fibroblastic
cells for S100, CD34 and vimentin; epithelial mem-
brane antigen, desmin and muscle-specific antigen
were all negative. Based on these findings, the differ-
ential diagnosis was reduced to the well-differentiated
variant of liposarcoma (inflammatory subtype) or
atypical neurofibroma. Multicolour fluorescence in situ
hybridization (FISH)-based karyotyping was performed
as previously described and showed: 48-53,XY,+
der(15),+1–3r(1;12;20),+1,+1,3der(12)(20qter::hsr12::
1q::hsr12q::12?) 96–106,idemx2[cp15] 46,XY[20].
5
Both ring-like and giant marker chromosomes, char-
acteristic for well- and dedifferentiated liposarcoma
were seen (Figure 3A). Confirmatory FISH, using
bacterial artificial chromosome (BAC) probes showed
high-level amplification of the 1q and 12q regions
(Figure 3B).
The region on 12q13-21 contains several potential
oncogenes such as CDK4, GLI, SAS and MDM2.
Amplification of MDM2 has been described in both
well- and dedifferentiated liposarcoma of the retro-
peritoneum.
6
In fact, their presence serves as their
(cytogenetic) hallmark and has not been described in
the other tumours considered in the differential
diagnosis mentioned above. A recent study has
shown that MDM2 and CDK4 immunohistochemis-
try, correlating with gene expression, is useful in the
diagnosis of well- and dedifferentiated liposarcoma.
However, MDM2 and CDK4 immunoreactivity is not
specific and also occurs in leiomyosarcoma, myxo-
fibrosarcoma, and malignant peripheral nerve sheath
tumours.
7,8
Thus, combined binary ratio labelling
(COBRA)-FISH and confirmatory BAC-FISH seems
more sensitive and specific than immunohistochem-
istry with MDM2 and CDK4 alone.
7
Based on
histology, radiology and molecular cytogenetic anal-
ysis, a preoperative diagnosis of well-differentiated
liposarcoma was made, followed by laparotomy and
resection of the tumour. Macroscopic examination of
the tumour showed two large grey fibrous masses of
150 · 80 · 95 mm and 60 · 50 · 38 mm, which
were yellow and fleshy on cut surface (Figure 2B).
**
**
AB C
Figure 1. Computed tomography scan of the abdomen. A, Mass lesion posteriorly in the right abdominal wall invading the oblique abdominal
and quadratus lumborum muscles (arrows). A large tumour component containing fatty tissue extends toward the retroperitoneum.
Enlargement and heterogeneity of the right psoas muscle (*). B, Rounded mass posterior to the second part of the duodenum (**). C, Infiltration of
the whole right perirenal space in contunuity with the abdominal wall tumour (arrowheads).
Correspondence 423
2007 The Authors. Journal compilation 2007 Blackwell Publishing Ltd, Histopathology, 51, 405–432.
Page 2
Extensive histological sampling demonstrated well-
differentiated areas of adipocytic proliferation with
marked variation in diameter of the fat vacuoles
(Figure 2C). These areas also contained fibrous bands
and, within these bands, the presence of atypical
cells showing hyperchromatic and vacuolated nuclei
A B
CD
EF
Figure 2. Morphological spectrum of the tumour. Trucut biopsy specimen of the tumour showing a fibrillary collagenous background with
hyperchromatic vacuolated nuclei of the stromal cells (A). The surgical specimen shows a nodular yellowish mass (B). Microscopic examination
of the latter shows areas of well-differentiated adipocytes with significant variation in cell size (C) divided by fibrous bands containing bizarre,
hyperchromatic stromal cells (D). No mitotic figures or necrotic areas can be seen. In other areas a chronic inflammatory condition predominates
(E). There is obvious growth into the psoas muscle (F).
424 Correspondence
2007 The Authors. Journal compilation 2007 Blackwell Publishing Ltd, Histopathology, 51, 405–432.
Page 3
(Figure 2D). Other areas showed fibrillary colla-
genous stroma with large collections of lymphocytes
(Figure 2E). There was clear infiltration of the
tumour cells in the surrounding striated muscle
(Figure 2F). No areas of dedifferentiation or myxoid
foci were present. The final diagnosis of well-
differentiated liposarcoma with both an inflammatory
and sclerotic component was made. The patient is
doing well and MRI has shown no local recurrence
18 months postoperatively.
1
A
B
234 5
1211109876
13
19 20 21 22 Y X
14 15 16 17 18
Figure 3. Karyotype of the tumour cells using combined binary ratio labelling-fluorescence in situ hybridization (COBRA-FISH). A, Representative
karyogram of a tumour cell after COBRA-FISH hybridization. Inset shows the types of giant, rod-like and ring chromosomes observed. B, Results
using 2 · 2 BAC probes for 1q (RP11-190A12, RP11-277C14) in green and for 12q (RP11-366L20, RP11-314D7) in red. Interphase
cells of the tumour show nuclear bLeps containing amplified 1q and 12q sequences, generally amplified in atypical lipomatous tumours
well-differentiated liposarcoma or dedifferentiated liposarcoma. Inverted 4¢,6-diamidino-2-phenylindole image shows bridges to the amplicon
carrier regions.
Correspondence 425
2007 The Authors. Journal compilation 2007 Blackwell Publishing Ltd, Histopathology, 51, 405–432.
Page 4
S M Willems
K Szuhai
1
H Hartgrink
2
J V M G Bove
´
e
A De Schepper
3
P C W Hogendoorn
Departments of Pathology,
1
Molecular Cell Biology,
2
Surgery and
3
Radiology, Leiden University Medical
Centre, Leiden, the Netherlands
1. Graadt van Roggen JF, Hogendoorn PCW. Soft tissue tumours of
the retroperitoneum. Sarcoma 2000; 4; 17–26.
2. Dei Tos AP, Pedeutour F. Atypical lipomatous tumour well
differentiated liposarcoma. In Fletcher CDM, Unni KK, Mertens F
eds. World Health Organization classification of tumours. Pathology
and genetics of tumours of soft tissue and bone. Lyon: IARC Press,
2002; 35–37.
3. Meis-Kindblom JM, Sjogren H, Kindblom LG et al. Cytogenetic and
molecular genetic analyses of liposarcoma and its soft tissue
simulators: recognition of new variants and differential diagnosis.
Virchows Arch. 2001; 439; 141–151.
4. Verstraete KL, Van der Woude HJ, Hogendoorn PCW, de Deene Y,
Kunnen M, Bloem JL. Dynamic contrast-enhanced MR imaging of
musculoskeletal tumors: basic principles and clinical applications.
J. Magn. Reson. Imaging 1996; 6; 311–321.
5. Szuhai K, Tanke H. COBRA: combined binary ratio labeling of
nucleic-acid probes for multi-color fluorescence in situ hybridiza-
tion karyotyping. Nature Protocols 2006; 1; 264–275.
6. Dei Tos AP, Doglioni C, Piccinin S et al. Coordinated expression
and amplification of the MDM2, CDK4, and HMGI-C genes in
atypical lipomatous tumours. J. Pathol. 2000; 190; 531–536.
7. Binh MB, Sastre-Garau X, Guillou L et al. MDM2 and CDK4
immunostainings are useful adjuncts in diagnosing well-differen-
tiated and dedifferentiated liposarcoma subtypes: a comparative
analysis of 559 soft tissue neoplasms with genetic data. Am. J.
Surg. Pathol. 2005; 29; 1340–1347.
8. Coindre JM, Hostein I, Maire G et al. Inflammatory malignant
fibrous histiocytomas and dedifferentiated liposarcomas: histolog-
ical review, genomic profile, and MDM2 and CDK4 status favour a
single entity. J. Pathol. 2004; 203; 822–830.
Meningiomas do not express CD117 (KIT)
DOI: 10.1111/j.1365-2559.2007.02783.x
Sir: The transmembrane receptor CD117 (KIT) has
been shown to be constitutively expressed in gastro-
intestinal stromal tumours (GISTs), in most cases
owing to activating mutations in the corresponding
c-kit gene and resulting in increased tyrosine kinase
activity of the KIT protein. The knowledge of this
pivotal signalling pathway in GISTs has been the basis
for successful adjuvant treatment using Imatinib
mesylate (Gleevec
), in particular in metastatic and
unresectable GISTs.
1
Subsequently, a variety of other
mesenchymal and non-mesenchymal cells and
tumours have been shown to express CD117, such as
seminoma, mastocytosis, malignant melanoma and
several soft-tissue tumours.
2
In tumours of the central
and peripheral nervous system, CD117 expression has
been reported for malignant peripheral nerve sheath
tumours,
3
neoplastic Schwann cells,
4
gliomas
5
and
medulloblastomas.
6
In addition, a case of meningeal
solitary fibrous tumour has been reported to be
CD117+.
7
However, the expression of CD117 in
meningiomas has not previously been studied. Menin-
giomas comprise about 25% of primary brain tumours.
Most meningiomas are slowly growing benign tu-
mours, but atypical World Health Organization (WHO)
grade II and anaplastic WHO grade III meningiomas
with aggressive clinical behaviour and substantially
reduced survival rates occur in about 15–20% and
1–2%, respectively.
8
Despite surgery, treatment options
for these aggressive meningioma variants are currently
limited to radiation.
9
Moreover, meningiomas have
been reported to occur rarely in other parts of the body,
e.g. in the lung,
10
and may pose a diagnostic challenge,
in particular if a spindle-cell pattern (fibroblastic type)
dominates. Therefore, knowledge of CD117 expression
in meningiomas is of interest both for differential
diagnosis from other mesenchymal tumours as well as
for potential new treatment options of atypical or
anaplastic meningiomas.
Therefore, we have investigated 37 intracranial
meningiomas of different WHO grade (13 grade I
tumours, including six meningothelial, five fibroblastic
and two transitional meningiomas, 15 grade II and
nine grade III meningiomas) by immunohistochemistry
using an antibody directed against human KIT [MBL,
Nagoya, Japan; dilution 1 : 200; microwave pretrea-
ment (20 min ethylenediamine tetraaceticacid)]. A
GIST of the stomach served as positive control; a
negative control (omission of the primary antibody)
was also included.
CD117 was detected in 0 13 grade I meningiomas,
0 15 grade II tumours and in only one grade III
meningioma (1 9). In this tumour, immunoreactivity
showed a membranous and cytoplasmic staining
pattern of moderate intensity (Figure 1A). It was
unevenly distributed, with a cluster-like arrangement
of immunopositive tumour cells, constituting approx-
imately 20% of all tumour cells. In each tumour,
several CD117+ mast cells were found that also served
as an internal control (Figure 1B). Whereas brain mast
cells are CD117–, mast cells within the normal
meninges, as in other body parts, usually express
426 Correspondence
2007 The Authors. Journal compilation 2007 Blackwell Publishing Ltd, Histopathology, 51, 405–432.
Page 5