Diagnostic Center for Population and Animal Health, College of Veterinary Medicine, Michigan State University, Lansing, MI 48910, USA.
Vet Pathol. 2013 Sep;50(5):779-88. doi: 10.1177/0300985813478211. Epub 2013 Mar 1.
Canine nonangiogenic, nonlymphogenic, gastrointestinal sarcomas have been previously diagnosed as gastrointestinal stromal tumors (GIST), leiomyosarcomas, or nonspecified spindle cell sarcomas, but diagnostic criteria for each entity are poorly defined. We propose a classification for canine nonangiogenic, nonlymphogenic, gastrointestinal sarcomas based on microscopic, immunohistochemical, and molecular characteristics. Applying the classification to 40 canine nonangiogenic, nonlymphogenic, gastrointestinal sarcomas documented its diagnostic and prognostic value. Eighteen (45%) sarcomas were classified as GIST based on positive KIT immunoreactivity. All GISTs were positive for vimentin, 14 (78%) were positive for S-100, and 6 (33%) were positive for smooth muscle actin (SMA). In contrast to their human counterparts, canine GISTs occurred mainly in the small intestine (67%) but commonly metastasized (5/18) to liver, lymph nodes, and omentum. Six GISTs had an activated KIT mutation in exon 11 of c-Kit, but no mutations were detected in exons 8, 9, 13, and 17. Twelve (30%) sarcomas were classified as leiomyosarcomas based on positive labeling for SMA and negative labeling for KIT. Four of these neoplasms were well differentiated leiomyosarcomas characterized by weak to no labeling for vimentin, and 8 were poorly differentiated leiomyosarcomas characterized by strong labeling for vimentin. None of the leiomyosarcomas metastasized, but poorly differentiated leiomyosarcomas had a higher risk of local invasion. Ten (25%) sarcomas were classified as non-GIST/nonleiomyosarcomas that were negative for KIT and SMA but positive for vimentin and either S-100 and/or PGP 9.5. These neoplasms most likely represent sarcomas of neurogenic differentiation resembling Schwann cells or perineurial or endoneurial fibroblasts, respectively.
犬非血管性、非淋巴性胃肠道肉瘤之前被诊断为胃肠道间质瘤（GIST）、平滑肌肉瘤或未特指的梭形细胞肉瘤，但每种肿瘤的诊断标准定义较差。我们根据微观、免疫组织化学和分子特征提出了犬非血管性、非淋巴性胃肠道肉瘤的分类。将该分类应用于 40 例犬非血管性、非淋巴性胃肠道肉瘤中，证明了其诊断和预后价值。18 例（45%）肉瘤根据 KIT 免疫反应阳性被归类为 GIST。所有 GIST 均为波形蛋白阳性，14 例（78%）为 S-100 阳性，6 例（33%）为平滑肌肌动蛋白（SMA）阳性。与人类 GIST 不同，犬 GIST 主要发生在小肠（67%），但常转移（5/18）至肝脏、淋巴结和大网膜。6 例 GIST 在 c-Kit 的外显子 11 中具有激活的 KIT 突变，但在 8、9、13 和 17 外显子中未检测到突变。12 例（30%）肉瘤被归类为平滑肌肉瘤，根据 SMA 阳性和 KIT 阴性标记。其中 4 种肿瘤为分化良好的平滑肌肉瘤，其特征为波形蛋白弱阳性至阴性，8 种为分化不良的平滑肌肉瘤，其特征为波形蛋白强阳性。没有平滑肌肉瘤发生转移，但分化不良的平滑肌肉瘤局部侵袭的风险更高。10 例（25%）肉瘤被归类为非 GIST/非平滑肌肉瘤，对 KIT 和 SMA 呈阴性，但对波形蛋白呈阳性，并且对 S-100 和/或 PGP 9.5 呈阳性。这些肿瘤最可能代表神经分化的肉瘤，类似于施万细胞或神经外膜或神经内膜成纤维细胞。
