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Desmoplastic small
round cell tumor: a clinicopathologic, immunohistochemical and
molecular study of four patients.J
Formos Med Assoc. 2007 Oct;106(10):854-60
BACKGROUND/PURPOSE: Desmoplastic small round cell tumor (DSRCT) is a
rare but highly aggressive tumor that usually occurs in the abdominal
cavity of young males. Immunohistochemical staining plays an important
role in the differentiation of DSRCT from other small round cell
neoplasms. Recently, a novel translocation of chromosome 11 and 22
[t(11;22)(p13+q12)] was identified in DSRCTs, which could result in
the formation of the chimeric EWS-WT1 fusion gene. Reverse
transcriptasepolymerase chain reaction (RT-PCR) has been applied to
detect the fusion gene in fresh tissue and confirm the diagnosis. Only
a few studies using RT-PCR with formalin-fixed and paraffin-embedded (FFPE)
tissue sections to detect the specific transcript have been reported.
METHODS: We collected four patients who had been diagnosed with DSRCT
from the archives of the Department of Pathology, National Taiwan
University Hospital, between 1996 and 2006. The clinical information
and histologic sections of the patients were reviewed. Panel of
primary antibodies including cytokeratin, vimentin, desmin and WT-1
were used for immunohistochemical staining. RNA extracted from the
FFPE tissue sections was used for RT-PCR to identify the transcript of
EWS-WT1. RESULTS: All four patients were male, with a mean age of 24
years. All of the tumors originated in the abdominal cavity and liver
metastases were found in two patients. Two patients died of disease
within 2 years, and the other two remained alive with disease.
Histologically, the tumors were composed of nests of primitive small
round cells within a desmoplastic stroma. Immunohistochemically, all
the tumor cells were reactive to cytokeratin, vimentin, desmin and
WT-1. The characteristic EWS-WT1 fusion gene could be identified in
the FFPE specimens of all three patients who had tissue sections
available for RT-PCR analysis. CONCLUSION: DSRCT is an aggressive
tumor that usually occurs in the peritoneum of young males. The tumor
is characterized by the expression of cytokeratin, vimentin, desmin
and WT-1. RT-PCR, using paraffin-embedded tissue sections, can
effectively detect the characteristic EWS-WT1 fusion gene transcript. |
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Desmoplastic small round cell
tumour
Visit: Soft Tissue Pathology
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Desmoplastic small round cell tumor: a clinicopathologic,
immunohistochemical, and molecular study of 32 tumors.Am
J Surg Pathol. 2002
Jul;26(7):823-35
Desmoplastic
small round cell tumor is a rare, aggressive neoplasm that mainly
affects young male patients and is characterized by a reciprocal
translocation t(11;22)(p13;q12) associated with the EWS-WT1 gene
fusion transcript. Clinical, histopathologic, immunohistochemical,
and molecular genetics features were reviewed for 32 tumors. There
were 29 male and three female patients, with ages from 6 to 54 years
(mean, 25 years). The main clinical signs and symptoms included
abdominal pain (eight patients), weight loss (five patients), and
presence of umbilical hernia (four patients). Two tumors primarily
involved the ethmoid sinus and the soft tissues of the scalp; the
other tumors (mean size, 10 cm) involved the abdominal cavity (88%).
One patient presented initially with an axillary lymph node
metastasis. Generally, all tumors showed the typical histologic
findings of variably sized clusters of small, round, or spindled
cells lying in a desmoplastic stroma. The neoplastic cells in
formalin-fixed, paraffin-embedded tissue sections were positive for
desmin (dot pattern) (81% of the cases), WT1 (91%), keratin (87%),
neuron-specific enolase (84%), CD99 (23%), and actin (3%). The
EWS-WT1 gene fusion transcript was detected in 29 of 30 tumors. One
tumor with typical clinicopathologic and immunohistochemical
features did not show the gene fusion. Follow-up for 27 patients
showed that 19 patients (70%) died of uncontrolled, local, or
widespread metastatic disease 3-46 months (mean, 20 months) after
diagnosis, and eight patients were alive with known evidence of
disease. Occasionally, desmoplastic small round cell tumor lacks the
classic clinical, histologic, and immunohistochemical features. This
study emphasizes the utility of analysis of the EWS-WT1 gene fusion
transcript, which was performed on paraffin-embedded tissues, to
confirm the diagnosis. |
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February 2008
Myxoid
Tumours of Soft Tissue
Classification
of Soft Tissue Tumour
Gross examination of soft tissue specimen |
