96. Jahrestagung der Deutschen Gesellschaft für Pathologie e. V ...

Abstracts
Conclusions. PDGFRA-mutated GISTs are rather large tumors of gastric
site with a very low/low risk of progression. D842V is the most common
mutation. Overall, GISTs with PDGFRA mutations exhibit a low degree
of chromosomal instability, compared to KIT-mutated GISTs. Although
PDGFRA-mutated GISTs principally display the same chromosomal
aberrations as KIT-mutated GISTs, the observed low degree of chromosomal
instability might contribute to their generally low malignant phenotype.
FR-P-064
Rare inflammatory pseudotumor with primary (intrapulmonal,
mediastinal, subpleural) manifestation and subsequent occurrence
within mesenteric fatty tissue of the small intestine – secondary
tumor lesion or metastasis?
M . Petersen1 , H . Lippert1 , K . Schütte2 , A . Roessner3 , F . Meyer1 1 2 University Hospital, Dept . of Surgery, Magdeburg, University Hospital,
Dept . of Gastroenterology, Magdeburg, 3University Hospital, Institute of
Pathology, Magdeburg
Aims. The rarely occurring inflammatory pseudotumor (IPT) is considered
a relevant differential diagnosis in regard to frequency, identifiability
and adequate management in diagnostic and therapy of intestinal tumor
lesions.
Methods. By means of an extraordinary case report, this tumor finding is
characterized with occurrence, finding the correct diagnosis, therapeutic
measures and outcome.
Results. In a 39-year-old man, a multifocal recurrent tumor growth within
the thorax (intrapulmonary, mediastinal, subpleural lesions – predominating
within the right upper segment) and a singular abdominal
tumor lesion were diagnosed 12 years after a former successfully resected
pulmonary first manifestation of an IPT. An in-toto resection of the
middle jejunal segment was achieved because of a manifest inflammatory
tumor conglomerate consisting of mesenteric fatty tissue and attached
jejunal loops including a jejunojejunostomy with an uneventful
postoperative course. A surgical re-intervention for the pulmonary/thoracic
tumor lesions was not favored by the thoracic surgeons because of a
superior vena-cava-neighbored tumor site with mediastinal infiltration.
Initially, the patient did not agree to an externally recommended immunosuppressive
treatment with cyclophosphamide and steroids because of
a wish for a baby despite repeatingly expressed demands. Finally, the patient
underwent a 5-month systematic steroid therapy and subsequently,
a periodic repeat of such therapeutic cycles but, however, with no CT
follow-up as recommended. A slight tumor progression was diagnosed.
Histopathological investigation revealed myofibroblastic cell proliferation
and inflammatory infiltrates; in addition, the immunohistochemical
test marker profile (CD117-, Alk1-, chromogranine-negative; vimentin-
and partially SM-actin-positive) led to the diagnosis IPT.
Conclusions. After appropriate literature search, the presented patient is
one of the only few cases with an IPT of the described unusual tumor
site within the jejunal mesenteric tissue, a rare multifocal recurrent tumor
growth after former surgical resection through a long-term course
of 12 years.
104 | Der Pathologe · Supplement 1 · 2012
FR-P-065
Tissue damage through MRI histopatology of small intestine in
swine model due to high frequency radiation of different intensity
and duration
S . Griff1 , T . Mairinger1 , G . Stoltenburg-Didinger 2
1 2 HELIOS Klinikum Emil v . Behring, Berlin, Institute for Cellbiology and
Neurobiology Charité Berlin
Aims. Magnetic resonance imaging (MRI) is an important diagnostic
tool in daily clinical praxis. Regarding the physical aspects, the majority
of radiofrequency (RF) power transmitted for imaging is transformed
into heat within the patient’s body. The thresholds of exposure (specific
absorption rate, SAR) have been defined in the early 1980s without investigation
of changes of internal organs. The changes of organs due to
the impact of high frequency radiation have not been investigated since.
Based on these facts we evaluated the morphological effects in small intestine
in swine in correlation to SAR and core temperature.
Methods. By autopsy, small intestine tissue from 14 pigs was examined by
histology and immunohistochemistry. The animals have been exposed
to long-time whole-body SAR. There were four groups of animals with
different SARs and duration of exposure. The control group (group 0)
was not exposed. The highest exposure was beyond the SAR thresholds.
Results. All exposed animals irrespective of dose and duration of exposure
showed marked histological changes. These were:
– Loss and/or necrosis of surface epithelium
– Hyperaemia
– Focal fibrin thrombi
– Retraction of villi
– Lymphocytic and eosinophilic infiltration of lamina propria
Conclusions. The results of the present study question the so far valid
SAR thresholds. The casuistic reports of complications were considered
as handling error or patient’s erratic behaviour. Such cases have to be
re-evaluated and newly discussed, as there are no histological studies of
internal organs in these situations.
FR-P-066
Her2/neu in gastric cancer: comparison of tissue micro arrays with
corresponding whole tissue sections
C . Böger1 , V . Warneke1 , H .-M . Behrens1 , C . Röcken1 1Christian-Albrechts-University, Kiel, Institute of Pathology, Kiel
Aims. Gastric cancer (GC) is one of the most common causes of cancerrelated
deaths worldwide. The introduction of trastuzumab for Her2/
neu-positive gastric cancer is a recent advancement, with Her2/neu currently
being the only predictive biomarker for gastric cancer. Her2/neu
status is currently assessed by biopsy or resection material, but it is not
validated which influence tissue sampling has on the assessment of the
Her2/neu status.
Methods. 485 patients (299 men, 186 women; median age 68 years) with
GC had undergone either total or partial gastrectomy for adenocarcinomas
of the stomach or oesophago-gastric junction. Formalin-fixed and
paraffin-embedded tissue samples were used to generate tissue micro
arrays (TMA). Briefly, five representative regions of the paraffin “donor”
blocks were chosen. Tissue cylinders of 1.5 mm diameter were punched
from these areas and arrayed into a new “recipient” paraffin block. Afterwards,
4 µM sections of the resulting tumor TMA-block were cut for
further analysis. The Her2/neu-status was assessed using the monoclonal
anti-Her2/neu-antibody (clone 4B5) and HER2-SISH double labelling in
situ hybridization-system, according to the gastric cancer scoring system
by Rüschoff et al. (Virch Arch. 2010 Sep; 457(3):299–307) separately for
resection specimens (whole tissue sections) and for biopsies (TMAs) in
order to test which influence tissue sampling has on the Her2/neu-status.
Statistical analyses: For measuring the inter-rater agreement of Her2/neu
scores between two observers, Cohen’s kappa coefficient was calculated.