Metaplastic carcinoma with extensive chondroid differentiation in the breast (chondroid carcinoma)

Metaplastic breast carcinoma is very rare, and metaplastic carcinoma with chondroid differentiation is even rarer. Here, we report a case of metaplastic carcinoma with extensive chondroid differentiation mimicking chondrosarcoma that was challenging to diagnose. The tumor was characterized by an abundant chondromyxoid matrix. The definitive area of classic invasive ductal carcinoma was minimal. The peripheral portion of the tumor showed increased cellularity with pleomorphism and definitive invasive growth. Tumor cells in the chondrosarcomatous areas were diffusely immunoreactive for S-100 protein, patchy positive for cytokeratin, but negative for epithelial membrane antigen (EMA). Tumor cells in carcinomatous areas were diffusely positive for cytokeratin, S-100 protein, and patchy positive for EMA. In both areas, tumor cells were negative for smooth muscle actin (SMA) and CD34, while oncoprotein p53 was overexpressed. When pathologists encounter breast tumors with chondroid differentiation, careful sampling and immunohistochemistry for cytokeratin and SMA are most helpful to differentiate metaplastic carcinoma from malignant phyllodes tumor and malignant adenomyoepithelioma.     

Desmin-positive and alpha-smooth muscle actin positive chondrocytes in human defective articular cartilage--preliminary report

We studied the results of immunostaining for S-100 protein, alpha-smooth muscle actin, muscle specific actin and desmin in articular cartilage specimens obtained during an arthroscopy from eight patients with different degrees of osteoarthritis of the knee joint. In all cases, most of the cartilage cells were strongly positive for S-100 protein. Actin positive chondrocytes were present in four samples showing repair cartilage changes with occurrence of fibrocartilage tissue. Moreover, in one case, we observed typical desmin-positive chondrocytes in the layer of cartilage filling the defect of the articular cartilage surface. The expression of desmin can be regarded as a reaction to trauma or the indication of an inherent abnormality. The chondrocytes probably switched on smooth muscle features during the healing process, because desmin is to a great extent a typical muscle cell marker. This fact could probably support our previous supposition that cartilage cells expressing muscle markers could be designated as myochondroblasts and myochondrocytes analogously to the terminology of myofibroblasts. It is possible that during the healing of the cartilage defects, such a transformation of the immunophenotype of the cartilage cells is quite frequent, but it could also be only transient nature only.     

Elastofibroma: a clinicopathologic and immunohistochemical study of seven cases and literature review

Elastofibroma is a rare fibrous lesion characterized by accumulated abnormal elastic fibers whose etiology remains largely unknown. In this study, we analyzed seven cases of elastofibroma to further explore the characteristics of its cellular composition. Immunohistochemistry was performed for mast cell tryptase, S-100 protein, vimentin, CD34, smooth muscle actin, desmin and collagen type IV. Histochemical staining methods for Gomori's trichrome and Verhoeff elastica-van Gieson were also evaluated. Histopathologically, a haphazard array of collagen, eosinophilic amorphous fibers, and globules in a fibrous tissue was seen. The elastic nature of the fibers was confirmed by elastic stain, and with Gomori's trichrome collagen fibers were also demonstrated. The interspersed spindle or stellate cells were almost consistently positive for vimentin and frequently positive for CD34. Mast cell tryptase-positive cells were present in five of the cases. Collagen type IV immunoreactivity was seen in two cases. No staining was observed with smooth muscle actin, desmin or S-100 protein. Our findings suggest that CD34-positive mesenchymal cells are an integral component of elastofibroma.     

Intranodal palisaded myofibroblastoma

Intranodal palisaded myofibroblastoma (IPM) usually presents as a painless, slow-growing inguinal mass. Our review of 42 cases from 13 publications indicates that two thirds of IPMs occur between the ages of 45 and 55 years, the male-female ratio is 2:1, and there is a lack of ethnic predilection. Grossly, the IPM cut surface shows areas of hemorrhage. Five microscopic features are seen: (a) compressed remnants of lymphoid tissue at the periphery; (b) spindle cells with nuclear palisading; (c) intraparenchymal hemorrhage and erythrocyte extravasation; (d) so-called amianthoid fibers; and (e) intracellular and extracellular fuchsinophilic bodies that stain positive for smooth muscle actin. Immunohistochemically, IPM is positive for smooth muscle actin and cyclin D1 and negative for S100, glial fibrillary acidic protein, CD34, and desmin, and it shows a low proliferative index of Ki-67. Electron microscopy demonstrates features of myofibroblasts and smooth muscle cells. Excellent prognosis is seen after surgical treatment, with an approximately 6% recurrence rate and no malignant transformation.     

Myofibroblastoma of the ovary: report of a case.

We report an unusual case of an ovarian tumor arising in a 22-year-old female that showed histologic, immunohistochemical, and ultrastructural features of myofibroblastic differentiation. The mass was found incidentally and upon excision was 9.0 cm in its greatest dimension and almost entirely replaced the left ovary. The patient is alive without evidence of disease 21 months after excision. Histologically, the tumor was encapsulated and composed of cytologically bland spindled cells arranged into a variety of patterns, similar to those found in both solitary fibrous tumor and hemangiopericytoma. Immunohistochemically, the cells stained strongly for smooth muscle actin and muscle-specific actin, with only focal and weak staining for CD34. Stains for S-100 protein, desmin, and AE1/AE3 were negative. Ultrastructurally, the neoplastic cells showed clear-cut evidence of myofibroblastic differentiation. The differential diagnostic considerations, including solitary fibrous tumor and hemangiopericytoma, are discussed.     

Superficial malignant peripheral nerve sheath tumor: a rare and challenging diagnosis

We reviewed the clinicopathologic features of 5 cases of malignant peripheral nerve sheath tumor (MPNST) manifesting in superficial locations associated with cutaneous neurofibromas (4 cases) or superficial peripheral nerve (1 case). Four cases had spindle cell morphologic features and were at least focally positive for S-100 protein, whereas the associated benign neural elements had more extensive S-100 immunoreactivity. The single epithelioid case was diffusely and strongly positive for S-100 protein. Melanoma markers, epithelial membrane antigen, glial fibrillary acidic protein, neurofilament, pancytokeratin (AE1/AE3), CD34, smooth muscle actin, and desmin were negative in all cases. There were no local recurrences, but 3 patients died of metastatic disease within 2 to 30 months (median, 21 months). MPNSTs can occur in a superficial location and may have an aggressive clinical course. Immunohistochemical markers are helpful in excluding other lesions in the differential diagnosis. However, identification of a benign precursor or origin from a nerve may be the most definitive way to properly classify these rare lesions.     

Actin expression in neural crest cell-derived tumors including schwannomas, malignant peripheral nerve sheath tumors, neurofibromas and melanocytic tumors

Tumors that originate from neural crest-derived cells represent a heterogeneous group of neoplasms including benign and malignant tumors with melanocytic and schwannian differentiation. The immunophenotype of these tumors is well known but little is known about the expression of smooth muscle/myofibroblastic markers in these tumors. A total of 590 neural crest-derived tumors (50 benign schwannomas, five malignant peripheral nerve sheath tumors, 80 neurofibromas, 240 nevocytic nevi, 115 primary melanomas, and 100 melanoma metastases) were studied with respect to α-smooth muscle actin and muscle-specific actin expression. α-Smooth muscle actin and muscle-specific actin-positive tumor cells with a co-expression of S-100 protein were found in one benign schwannoma, one primary cutaneous melanoma, and four melanoma metastases. Four of these cases were examined ultrastructurally, but typical actin filaments with focal densities were not found in any of the four. Other immunohistochemical markers examined including desmin, h-caldesmon and smooth muscle myosin heavy chain were negative in the tumor cells. The present results suggest that neural crest-derived tumors could show expression of α-smooth muscle actin on rare occasion.     

Chondromyxoid fibroma

Chondromyxoid fibroma is a benign chondroid tissue tumor characterized by the lobular overgrowth of stellate or elongated cells in the myxoid or chondroid intracellular matrix. There may be giant multinucleate cells. They may be encountered in any skeletal bones, mainly at the age of 20-30 years. A positive reaction with S-100 protein, d smooth muscle actin, and CD 34 was immunohistochemically detected in chondromyxoid fibroma tissue. In chondromyxoid fibroma, the prognosis is favorable. Recurrence of the tumor is observed in 15% of the surgically treated cases.     

Cell markers in gastrointestinal stromal tumors

Stromal tumors of the gastrointestinal (GI) tract have generated considerable controversy about their direction and level of differentiation, particularly about whether the tumor cells are smooth muscle or Schwann cells. In an attempt to characterize these tumors, the immunohistochemical staining patterns of desmin, vimentin, actin, and S-100 protein were studied in 41 GI stromal tumors, using the avidin-biotin method, and compared with normal host smooth muscle and nerve and with esophageal and uterine leiomyomas. Twenty gastric and one rectal tumor stained diffusely with vimentin and actin, but not with desmin, and had scattered strongly S-100-positive cells that might either be trapped Schwann cells or tumor cells. Twenty small bowel tumors stained similarly to the gastric tumors with regard to vimentin, actin, and desmin, but most (17/20) had a unique, strongly positive geographic staining pattern with S-100. No differences in staining were noted between benign and malignant tumors in either gastric or small bowel sites, and most histologic patterns in tumors from similar locations stained similarly. These results suggest that GI stromal tumors are not truly "leiomyomas and leiomyosarcomas," but relatively undifferentiated tumors, with the expression of various antigens depending on their location in the gut.     

ULTRASTUCTURE OF CARTILAGINOUS TUMORS AND S-100 PROTEIN IN THE TUMORS: With Reference to the Histogenesis of Chondroblastoma, Chondromyxoid Fibroma and Mesenchymal Chondrosarcoma

Twelve cartilaginous tumors were studied by electron microscopy and the presence of S-100 protein was studied immunohistochemically in order to clarify the cell origin of chondroblastoma, chondromyxoid fibroma, and mesenchymal chondrosarcoma. Three chondroblastomas were characterized by round or ovoid tumor cells with some cytoplasmic processes, well-developed organelles and thick fibrous laminae in the nuclear membrane, occasional multinucleated giant cells and scanty chondroid matrix. S-100 protein was demonstrated in the tumor cells and some multinucleated giant cells. Two chondromyxoid fibromas revealed tumor cells of varied shapes with character istic cartilaginous differentiation and abundant chondroid matrix. Spindle tumor cells showed the ultrastructural features of cartilage cells rather than of fibroblasts and S-100 protein was also demontratrated in their cytoplasm. Chondroblastoma and chondomyxoid fibroma were considered to arise from chondrocytes. Mesenchymal chondrosarcoma ultrastructurally exhibited round tumor cells with cartilaginous nature in cartilage islands. Poorly-differentiated portions were composed of primitive round or elongated cells with occasionally admixed round cells with ultrastructural features of cartilaginous differentiation. S-100 protein was demonstrated in the cells in cartilage islands and in single cells admixed in poorly-differentiated portions. These results support the hypothesis of primitve mesenchymal origin with a tendency to differentiate toward cartilage cells. ACTA PATHOL. JPN. 34: 1285–1300, 1984.     

Myxoid mixed low-grade endometrial stromal sarcoma and smooth muscle tumor of the uterus. Case report

We report the case of a 73-year-old female with myxoid mixed low-grade endometrial stromal sarcoma and smooth muscle tumor of the uterus. Grossly, the tumor sized 130 x 130 x 100 mm involved the uterine corpus almost in its entirety. Histologically, the tumor consisted of two cell types. In some areas, the tumor cells showed typical features of endometrial stromal tumors and resembled stromal cells of proliferative endometrium. In other areas, however, the tumor showed smooth muscle features and consisted of larger mostly epitheloid cells with a moderate amount of cytoplasm. In all areas, myxoid changes and multiple hyalinizing giant rosettes were present. The tumor infiltrated the myometrium in a pattern typical of low-grade endometrial stromal sarcoma. Immunohistochemically, the tumor cells showed expression of vimentin, estrogen and progesterone receptors and variable expression of CD10, α-smooth muscle actin, desmin, h-caldesmon, and cytokeratin AE1/AE3. Other markers examined including CD99, α-inhibin, cytokeratin CAM5.2, S-100 protein, and HMB45 were negative. To the best of our knowledge, mixed low-grade endometrial stromal and smooth muscle tumor with myxoid changes has not been described to date.     

Collagenous fibroma (desmoplastic fibroblastoma) of the finger in a child

Collagenous fibroma (desmoplastic fibroblastoma) is a distinctive benign fibrous soft tissue tumor that typically occurs in the subcutaneous tissue or skeletal muscle in adults. We describe a case of collagenous fibroma in a 7-year-old boy who presented with a 1-cm solitary, firm nodule on the volar aspect of the metacarpophalangeal joint of the left little finger. Microscopically, the tumor was composed of spindle- and stellate-shaped cells embedded in a hypovascular, densely collagenous stroma. No mitotic figures, calcifications or necrosis were identified. Immunohistochemically, tumor cells were diffusely positive for vimentin, but negative for smooth muscle actin, muscle-specific actin, desmin, cytokeratin, S-100 protein or CD34. To our knowledge, this is the second reported case of collagenous fibroma in children. Our case report indicates that the clinicopathological features of collagenous fibroma in childhood are similar to those in adults.     

Papillary carcinoma of the thyroid with exuberant nodular fasciitis-like stroma

 We describe a rare case of papillary carcinoma with extensive proliferation of stromal cells. The stromal cells were immunocytochemically positive for vimentin, α-smooth muscle actin and desmin, but negative for cytokeratin, epithelial membrane antigen, S-100, thyroglobulin and CD34. These results and the ultrastructure of the stromal cells, which exhibited the characteristics of both fibroblasts and smooth muscle cells, indicated an origin from myofibroblasts. We conclude that myofibroblastic proliferation may contribute to the stromal response in the slow growth of the papillary carcinoma. Received: 29 August 1996 / 26 May 1997     

Distribution of chondrocytes containing alpha-smooth muscle actin in human normal, osteoarthrotic, and transplanted articular cartilage

The aim of our study was to evaluate the occurrence of chondrocytes containing alpha-smooth muscle actin in human normal and diseased cartilage. Immunohistochemistry using monoclonal antibodies for alpha-smooth actin, muscle-specific actin, S-100 protein, CD 34, and desmin was performed on samples of human articular cartilage obtained at autopsy following sudden death, during total hip and knee replacement for osteoarthritis, or after femoral neck fracture in patients without symptoms of osteoarthritis. Moreover, the layers of residual cartilage from chondral posttraumatic defects obtained during preoperative arthroscopy and of newly formed cartilage after autologous-chondrocyte transplantation (Hyalograft C) obtained during second-look arthroscopy were also examined by immunohistochemistry and RT PCR. Our study showed that a significant percentage of articular chondrocytes express alpha-smooth muscle actin in healthy, diseased, and regenerated articular cartilage. Alpha-actin positive chondrocytes (18%) were observed predominantly in the upper zone of normal articular cartilage. By contrast, only approximately 10% of cartilage cells in the deep region stained for this contractile actin isoform. Actin-positive chondrocytes (myochondrocytes) are formed predominantly in response to injury to the osteoarthrotic cartilage, at sites of defective healing, and in newly formed cartilage after autologous chondrocyte transplantation. Fibrocartilage is present in some of these conditions, and it is known that this tissue contains chondrocytes with actin. The presence of myochondrocytes in the surface layer of normal articular cartilage indicates that this region probably plays an important role in maintaining cartilage integrity. Myochondrocytes may utilize the contractile actin isoform in manipulating the extracellular matrix of articular cartilage. It is also possible that actin-containing chondrocytes have a higher potential for regeneration in contrast to chondrocytes that do not contain this contractile material in their cytoplasm.     

Desmin expression in spindle cell lipomas: a potential diagnostic pitfall

The immunohistochemical analysis of the spindle cell lipomas has been for the most part limited to the study of S-100 protein, CD34, and Bcl-2 reactivity. To evaluate the immunoexpression of desmin and actins in spindle cell lipomas of different histological subtypes a retrospective immunohistochemical study of 25 spindle cell lipomas using archival formalin-fixed, paraffin-embedded tissue was performed. Strong positivity of the spindle cell component for desmin was found in 4 of 25 cases (16%). The expression was diffuse in two cases and focal (in up to 25% of the spindle cells) in the other two. Two of these cases were of the classical type and the other two were angiomatous spindle cell lipomas. Desmin-positive and desmin-negative spindle cells showed no morphological differences. The spindle cell component expressed CD34 in all cases and Bcl-2 in 14 of the 25 cases. There was no immunoreactivity for smooth muscle actin, muscle-specific actin, or S-100 protein. We conclude that a significant proportion of spindle cell lipomas express desmin, and therefore that the immunoreactivity for this antigen does not exclude the diagnosis, even in lesions with nonclassical histological features and/or atypical locations.     

Spindle cell epithelioma of the vagina shows immunohistochemical staining supporting its origin from a primitive/progenitor cell population

Spindle cell epitheliomas of the vagina (SCEVs) coexpresses epithelial and mesenchymal markers and were first described as a "mixed tumors of the vagina." However, unlike mixed tumors of other organs, which are believed to originate from myoepithelial cells, SCEVs neither immunohistochemically nor ultrastructurally show features of myoepithelial cells. The present expanded battery of immunohistochemical stains is presented on this rare tumor, including cytokeratin AE1/AE3, CK7, CK20, S100 protein, epithelial membrane antigen, alpha-smooth muscle actin, desmin, CD34, CD99, Bcl-2, vimentin, estrogen and progesterone receptors, and Ki-67. There was minimal expression of alpha-smooth muscle actin and negative staining with S100 protein, with coexpression of cytokeratins and vimentin and expression of estrogen and progesterone receptors, as previously reported in SCEVs. In addition, diffuse expression of CD34, CD99, and Bcl-2 immunohistochemical stains was found, which has not previously been reported. The coexpression of CD34, CD99, and Bcl-2 in SCEVs is consistent with its origin from a primitive/progenitor cell population.     

Myxoid solitary fibrous tumor: a study of seven cases with emphasis on differential diagnosis.

Focal myxoid change is a well-recognized feature of solitary fibrous tumor (SFT), but to date, predominantly myxoid examples of SFT have not been reported. We describe seven cases of SFT in which stromal myxoid change affected 50% or more of the tumor examined, thus obscuring typical diagnostic features. Patients ranged in age from 35 to 68 years old (median, 45 yr), with an equal sex distribution. Tumor locations included pleura, orbit, and periparotid subcutaneous tissue, as well as four cases in deep soft tissue (two in the abdominal wall and one each in the chest wall and thigh). Myxoid areas were identified grossly in four cases. Histologically, the lesions were composed of bland spindle cells disposed haphazardly or with a lacy or reticulated appearance in a myxoid, richly vascularized stroma These myxoid areas were punctuated by small cellular aggregates in four cases, and areas showing diagnostic features of SFT were present in five of seven primary excision specimens. Atypical features suggestive of malignancy were not present in any of the cases. Immunohistochemically, all of the seven cases stained positively for CD34 and CD99 (013), and all were negative for smooth muscle actin, desmin, S-100 protein, epithelial membrane antigen, and pan-keratin. There were no recurrences or metastases reported in four patients with limited follow-up (median duration, 19 mo). Recognition of this uncommon morphologic subset of SFT is important because of possible confusion, particularly in small biopsy specimens, with a variety of myxoid spindle cell neoplasms with different biologic potential. These include low-grade fibromyxoid sarcoma, myxoid synovial sarcoma, malignant peripheral nerve sheath tumor, low-grade myxofibrosarcoma, myxoid liposarcoma, myxoid spindle cell lipoma, myxoid neurofibroma, and so-called "hemangiopericytoma."     

An immunohistochemical and clinicopathological study of gastrointestinal stromal tumors

Immunohistochemical and clinicopathological features of 58 gastrointestinal stromal tumors (GIST) were studied. One occurred in the esophagus, 41 in the stomach, nine in the small intestine, and seven in the large intestine. By using indirect immunoperoxidase staining for Cajal cell markers (c-kit protein and CD34), smooth muscle markers (alpha-smooth muscle actin, desmin, heavy caldesmon and calponin) and Schwann cell markers (S-100 protein and Leu 7), GIST were classified into five groups, such as Cajal cell type (n = 9), myogenic type (n = 5), Schwann cell type (n = 2), mixed cell type (n = 40) and undifferentiated type (n = 2). c-kit Protein (42/58; 72%) and CD34 (45/58; 78%) were commonly and diffusely expressed in GIST. Novel smooth muscle markers, caldesmon (29/58; 50%) and calponin (18/58; 31%), were useful in detecting myogenic characters of GIST. S-100 protein was expressed in 16 (28%) tumors, two of which were also reactive with Leu 7 (CD57). Three small bowel tumors with skeinoid fibers expressed the Cajal cell markers, and were categorizable in GIST. Clinicopathological analyses using aggressive (n = 21) and non-aggressive (n = 21) GIST indicated that the malignant potential was correlated with the intestinal location, large tumor size, high cellularity, necrosis, solid (non-interlacing bundled) pattern of growth, negativity of c-kit protein and/or CD34, high mitotic count, and high MIB-1 labeling.     

CD117阴性胃肠道间质瘤的临床病理及免疫组织化学研究

目的 探讨免疫组织化学在形态学典型、免疫组织化学CD117阴性胃肠道间质瘤(GIST)诊断中的意义.方法 对10例CD117阴性、形态学典型的GIST进行c-kit基因第9、11、13、17号外显子及血小板源性生长因子受体α(PDGFRA)基因第12和18号外显子的基因检测,同时所有病例均进行CD117、CD34、平滑肌肌动蛋白(SMA)、结蛋白、S-100蛋白、WT-1、DOG-1 的免疫组织化学染色(EnVision法).结果 10例中8例完成c-kit及PDGFRA基因的检测,仅1例有c-kit基因第9号外显子突变,余未发现基因突变.10例CD117阴性的病例9例CD34阳性,2例SMA局灶阳性.结蛋白和S-100蛋白均阴性.DOG1弥漫阳性者5例,1例弥漫弱阳性,2例局灶阳性,2例阴性.4例WT-1弥漫阳性,2例局灶阳性,1例有散在肿瘤细胞阳性,3例阴性.结论 对胃肠道及胃肠道外形态学典型、但CD117阴性的GIST病例,联合应用多种免疫组织化学标记有助于诊断.DOG-1和WT-1可作为补充加入到CD117阴性GIST的诊断中.

Abstract：

Objective To study the immunophenotype and c-kit or platelet derived growth factor receptor alpha(PDGFRA)gene mutations in CD117-negative gastrointestinal stromal tumors(GISTs).Methods Ten cases of GISTs with typical histologic features but no CD117 expression were retrieved from the archival of Department of Pathology,Peking Union Medical College Hospital,China.The Cages were further evaluated for the presence of c-kit exons 9.11, 13 and 17 mutations and PDGFRA exons 12 and 18mutations.DNA was extracted from the paraffin-embedded tuinor tissue.The PCR products were sequenced directly for the mutations.An immunohistochemical study for CD117,CD34,smooth muscle actin,desmin,S-100 protein.WT-1 and DOC-1 Was also performed.Results Eight of the 10 Cases had the mutation tests completed.C-kit mumfion in exon 9 Wag detected in only one case.Amongst the 10 cases studied, CD34Wag expressed in 9 cases. Smooth muscle actin was focally positive in 2 cases.None of them expressed desmin or S-100 protein.DOG-1 and WT-1 were diffusely positive in 5 and 4 Cages.respectively.In addition.DOG1 Was diffusely but weakly positive in 1 case and focally expressed in 2 cages.Three cases were focally positive for WT-1.Conclusion Pathologic diagnosis of CD117-negative GISTs can be facilitated with the application of a panel of immunohistochemical markers.including DOG-1 and WT-1.     

CD117阴性胃肠道间质瘤的临床病理及免疫组织化学研究

目的 探讨免疫组织化学在形态学典型、免疫组织化学CD117阴性胃肠道间质瘤(GIST)诊断中的意义.方法 对10例CD117阴性、形态学典型的GIST进行c-kit基因第9、11、13、17号外显子及血小板源性生长因子受体α(PDGFRA)基因第12和18号外显子的基因检测,同时所有病例均进行CD117、CD34、平滑肌肌动蛋白(SMA)、结蛋白、S-100蛋白、WT-1、DOG-1 的免疫组织化学染色(EnVision法).结果 10例中8例完成c-kit及PDGFRA基因的检测,仅1例有c-kit基因第9号外显子突变,余未发现基因突变.10例CD117阴性的病例9例CD34阳性,2例SMA局灶阳性.结蛋白和S-100蛋白均阴性.DOG1弥漫阳性者5例,1例弥漫弱阳性,2例局灶阳性,2例阴性.4例WT-1弥漫阳性,2例局灶阳性,1例有散在肿瘤细胞阳性,3例阴性.结论 对胃肠道及胃肠道外形态学典型、但CD117阴性的GIST病例,联合应用多种免疫组织化学标记有助于诊断.DOG-1和WT-1可作为补充加入到CD117阴性GIST的诊断中.