Malignant Gastrointestinal Neuroectodermal Tumor: Clinicopathologic, Immunohistochemical,
Ultrastructural, and Molecular Analysis of 16 Cases With a Reappraisal of Clear Cell Sarcoma-like Tumors
of the Gastrointestinal Tract   (Am J Surg Pathol 2012;36:857–868)
读了这篇文献后，终于对于有些作者报道的发生在胃肠道的“透明细胞肉瘤样胃肠道肿瘤”，有了更加深刻的认识，作者认为发生在胃肠道的“透明细胞肉瘤样胃肠道肿瘤”，包括两种肿瘤，一种就是真正的透明细胞肉瘤（向黑色素方向分化），另一种就是所谓的胃肠道神经外胚层肿瘤（缺乏黑色素方向分化，而起源于胃肠道自主神经）
虽然罕见，但心中牢记，遇到时，免疫组织化学不符合时，这样可能自我解答我们心中的疑惑。
Abstract: The clinical, histologic, immunophenotypic, ultrastructural,
and molecular features of a distinctive gastrointestinal
tumor are described. Sixteen patients, 8 women and 8 men aged
17 to 77 years (mean age, 42 y; 63%less than 40 y) presented with
abdominal pain, intestinal obstruction, and an abdominal mass.
Mean tumor size was 5.2cm (range, 2.4 to 15.0 cm). The tumors
arose in the small bowel (10), stomach (4), and colon (2) and
were histologically characterized by a sheet-like or nested population
of epithelioid or oval-to-spindle cells with small nucleoli
and scattered mitoses. Five cases showed focal clearing of the
cytoplasm. Scattered osteoclast-type multinucleated giant cells
were present in 8 cases. The tumor cells were positive for S-100
protein, SOX10, and vimentin in 100% of cases, for CD56 in
70%, for synaptophysin in 56%, for NB84 in 50%, for NSE in
45%, and for neurofilament protein in 14% of cases. All cases
tested were negative for specific melanocytic, gastrointestinal
stromal tumors, epithelial, and myoid markers. Ultrastructural
examination of 5 cases showed features of primitive neuroectodermal
cells with clear secretory vesicles, dense-core granules,
occasional gap junctions, and no evidence of melanogenesis.
EWSR1 gene rearrangement was assessed by fluorescence in situ
hybridization in 14 cases. Twelve cases (86%) showed split
EWSR1 signal consistent with a chromosomal translocation
involving EWSR1. One case showed extra intact signals, indicating
that the nuclei possessed either extra copies of the
EWSR1 gene or chromosome 22 polysomy. Only 1 case showed
no involvement of the EWSR1 gene. Six cases demonstrated
rearrangement of the partner fusion gene ATF1 (46%), and 3
showed rearrangement of CREB1 (23%); 2 cases lacked rearrangement
of either partner gene. Clinical follow-up was
available in 12 patients and ranged from 1.5 to 106 months. Six
patients died of their tumors (mean survival, 32mo; 83% less
than 24 mo). At last follow-up, 4 patients were alive with regional,
lymph node, and liver metastases, and 2 patients were
alive with no evidence of disease. The tumor described here is an
aggressive form of neuroectodermal tumor that should be separated
from other primitive epithelioid and spindle cell tumors of
the gastrointestinal tract. The distinctive ultrastructural features
and absence of melanocytic differentiation serve to separate them
from soft tissue clear cell sarcomas involving the gastrointestinal
tract. The designation “malignant gastrointestinal neuroectodermal
tumor” is proposed for this tumor type.

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