Solitary fibrous tumor of the anterior mediastinum: a rare extrapleural neoplasm

Solitary fibrous tumors are uncommon spindle cell neoplasms originally thought to be restricted to the pleura. We describe a 62-year-old woman who presented with stridor and an anterior mediastinal mass. At thoracotomy, a 10.5 x 6.5 x 5.5 cm, circumscribed, firm mediastinal mass demonstrated no direct cardiac or pulmonary involvement. The tumor consisted of spindle cells organized in a patternless pattern with collagenous stroma and hemangiopericytoma-like vessels. Spindle cells were immunoreactive for CD34, CD99, desmin, vimentin and bcl-2 protein and a diagnosis of mediastinal solitary fibrous tumor was confirmed. The differential diagnosis of mediastinal solitary fibrous tumors is extensive and includes spindle cell thymoma, sarcomatoid carcinoma, malignant mesothelioma, inflammatory myofibroblastic tumor, peripheral nerve sheath tumors and various sarcomas. Despite their rarity in the mediastinum, solitary fibrous tumors can be recognized by their classic patternless morphology and immunophenotypic pattern. Their accurate classification is important, as solitary fibrous tumors are intermediate (rarely metastasizing) neoplasms that require complete surgical excision and long-term clinical follow-up for optimum therapy.     

孤立性纤维性肿瘤临床病理特征

目的探讨孤立性纤维性肿瘤（SFT）的临床病理学特点、免疫学表型及鉴别诊断。方法对5例SFT进行临床病理学分析,并用免疫组化（S-P法）技术检测CD34、CD99、Vim Des CD68和S-100蛋白的表达。结果肿瘤主要由纤维母细胞样梭形细胞呈束状、编织状及席纹状排列,有丰富的胶原纤维及多量瘢痕形成,细胞无异型,核分裂少或无,CD34、CD99和Vim弥漫强阳性,而Des、CD68及S-100蛋白均阳性。结论SFT大多为良性,可以根据病理形态及免疫组化来加以诊断及鉴别诊断,当镜下出现细胞丰富、密集,细胞有异型性,核分裂相增多（〉4个/10个HPF）,明显的坏死和出血并侵犯周围组织时,要考虑恶性可能。     

Recurrent intracranial solitary fibrous tumor initially diagnosed as hemangiopericytoma

We describe a case of an intracranial solitary fibrous tumor that recurred three times consecutively in an 11-year period. A 72-year-old man presented with a headache and gait disturbance. Magnetic resonance imaging (MRI) revealed a dumbbell tumor at the left tentorium. The tumor was removed but recurred. The first diagnosis was hemangiopericytoma, but all specimens showed a “patternless pattern” and few reticulin fibers, which features were not compatible with hemangiopericytoma. All tumors showed immunoreactivity for CD34 and bcl-2. These results point to a solitary fibrous tumor (SFT) and not to hemangiopericytoma. We present here a hypercellular spindle-cell tumor that was very similar to hemangiopericytoma but is better diagnosed as SFT.     

Expression of Ki-1 antigen (CD30) in mesenchymal tumors

Expression of CD30(Ki-1) antigen has long been considered to be restricted to activated lymphocytes and related tumors. However, expression of this antigen has also been detected in embryonal carcinomas, in nonembryonal carcinomas, in malignant melanomas, and even in some myeloid cell lines and macrophages at late stages of differentiation. In this study, using monoclonal antibody Ki-1, expression of CD30 antigen was immunohistochemically examined in frozen sections of 28 benign and 63 malignant mesenchymal tumors. The authors found CD30 expressed in two of four leiomyomas, seven of 11 leiomysarcomas, one of six rhabdomyosarcomas, two of two aggressive fibromatoses, one of three fibrosarcomas, two of four synovial sarcomas, one giant cell tumors of tendon sheaths, all five malignant fibrous histiocytomas, all three osteosarcomas, one of three Ewing's sarcomas, in a tumor cell subpopulation of two of ten malignant schwannomas, and in the Schwann cell compartment of one of two ganglioneuromas tested. Furthermore, CD30 was consistently expressed in the myoepithelial compartment of 13 fibroadenomas. However, all five lipomas, all seven liposarcomas, all three neuroblastomas, both ganglioneuroblastomas, both chondrosarcomas, and tumors of disputed origin tested were consistently CD30 negative. These findings indicate that, outside the lymphatic system, CD30 antigen is not restricted to epithelial neoplasms but may also be present in tumors of mesenchymal origin. The authors conclude that CD30 antigen, although having limited utility in the differential diagnosis of tumors of questionable histogenesis, may eventually define relevant subgroups within the main tumor categories.     

Well differentiated adult-type fibrosarcoma arising from the occipital subcutaneous tissue in a 17-year-old man: case report with immunohistochemical study

We report a case of a 17-year-old man with a spindle cell tumor in the occipital subcutaneous tissue. The enucleated tumor, measuring 2.5 x 2.0 x 1.0 cm, had a broad-bean shape and well circumscribed border and was localized to the subcutis without dermal involvement. Microscopically, the tumor was composed of uniform spindle cells showing interlacing bundle formation and a herringbone pattern. The neoplastic cells were separated by collagen fibers in parallel fashion, the amount of which varied with different areas in the tumor. Mitotic figures were eight mitoses per 50 high-power fields in number. The neoplastic cells were positive for vimentin, Factor-XIIIa, alpha-smooth muscle actin and CD34, but negative for desmin, calponin, high molecular weight caldesmon, smooth muscle myosin heavy chain, collagen type IV, laminin and S-100 protein. These immunohistochemical results indicated that the neoplastic cells showed differentiation toward fibroblasts/myofibroblasts/dendritic interstitial cells. Although more than 50% of the neoplastic cells were positive for CD34, the present tumor should be diagnosed as well differentiated fibrosarcoma, adult type, rather than extrapleural solitary fibrous tumor and fibrosarcomatous areas of dermatofibrosarcoma protuberans, on the basis of routine microscopic findings mentioned above.      

Neurofibroma of kidney: an uncommon neoplasm and diagnostic dilemma with solitary fibrous tumor

Neurofibroma of kidney is an extremely rare tumor. To our knowledge, only five such cases have been reported worldwide till date. Here, we report a solitary neurofibroma of right kidney in a 54-year-old woman. Radiological investigations (ultrasonography and computed tomography) detected a solid mass in the upper pole of right kidney and clinicoradiologically renal cell carcinoma was suspected. A radical nephrectomy was performed under diagnosis of cancer. Microscopically, tumor consisted of benign spindle-shaped cells accompanied by fibrous tissue. Differential diagnoses of neurofibroma and solitary fibrous tumor (SFT) were made on morphological features. Immunohistochemically, the tumor cells were positive for S-100 protein, but negative for CD34 and CD99. Thus, a diagnosis of neurofibroma was established.     

Transthoracic fine-needle aspiration biopsy of pulmonary spindle cell and mesenchymal lesions: a study of 61 cases

BACKGROUND: Spindle cell and mesenchymal lesions of the lung encompass a wide variety of benign and malignant conditions. However, to the authors' knowledge, because of their rarity, few reports concerning their cytologic findings are available in the literature. The current review emphasizes the cytomorphologic features, differential diagnosis, and potential pitfalls associated with these lesions. METHODS: Seven hundred seventy-nine percutaneous lung fine-needle aspiration (FNA) specimens were retrieved from the authors' cytopathology files over a period of 5 years. Sixty-one cases (7.8%) in which a spindle cell component was the dominant or key feature were identified. The authors reviewed the cytologic smears, immunocytochemical studies, and corresponding surgical material and clinical information. RESULTS: Of these 61 aspirates, 33 (54%) were reactive processes (31 granulomas, 1 organizing pneumonia, and 1 inflammatory pseudotumor). Five cases (0.8%) were benign neoplasms (2 hamartomas, 2 solitary fibrous tumors, and 1 schwannoma). Twenty-three cases (38%) were malignant neoplasms (8 cases were primary tumors [including 5 carcinomas with spindle cell or sarcomatoid features, 1 spindle cell carcinoid tumor, 1 leiomyosarcoma, and 1 synovial sarcoma] and 15 cases were secondary tumors [including 9 melanomas, 2 leiomyosarcomas, 1 malignant fibrous histiocytoma, 1 meningioma, 1 sarcomatoid renal cell carcinoma, and 1 uterine malignant mixed müllerian tumor]). A specific diagnosis was rendered in 52 cases (85%). No false-positive cases were encountered but there was one false-negative case. One patient who was diagnosed with granulomatous inflammation on FNA was found to have nonsmall cell lung carcinoma on subsequent transbronchial biopsy. No malignant cells were identified in the smears on review. The FNA from the organizing pneumonia was interpreted as a solitary fibrous tumor whereas the inflammatory pseudotumor was diagnosed as granulomatous inflammation. The FNA from one pulmonary hamartoma initially was considered to be nondiagnostic. One solitary fibrous tumor and the schwannoma were diagnosed as smooth muscle tumor and spindle cell tumor, not otherwise specified, respectively. Among the malignant tumors, the primary synovial sarcoma and one of the metastatic malignant melanomas initially were interpreted as primitive neuroectodermal tumor/Ewing sarcoma and poorly differentiated carcinoma, respectively. CONCLUSIONS: Spindle cell lesions of the lung rarely are encountered on transthoracic lung FNA and are comprised of a wide variety of benign and malignant entities. By correlating clinical and radiologic data, cytologic findings, and ancillary studies, a high diagnostic accuracy rate can be achieved with FNA.     

胃肠道间质瘤58例临床病理分析

 分析胃肠道间质瘤（GIST）的形态特点和免疫组织化学特征，探讨肿瘤的组织来源和分型。方法 对58例GIST进行光镜观察，用EnVision二步法免疫组织化学方法检测波形蛋白、CD117（c-Kit）、CD34等抗原标记物在肿瘤中的表达情况。结果 58例GIST占同期消化系统间叶性肿瘤的86.6 %（58／67）；其中梭形细胞为主者41例，伴有上皮样细胞者12例，单纯由上皮样细胞组成者5例，瘤细胞呈长、短梭形和圆形，胞质弱嗜酸，常见核端空泡，有时呈印戒样或透明细胞样；排列呈漩涡状、栅栏状或弥漫性巢状。免疫组织化学显示肿瘤组织中抗原标记物表达阳性率波形蛋白为100 %（58／58），CD117 94.8 %（55／58），CD34 79.3 %（46／58）。结论 GISTs是消化道最常见的间叶性肿瘤，光镜形态与真性肌源性和神经源性肿瘤极为相似，CD117、CD34等免疫标记物可对其作出正确诊断，GIST可能起源于多潜能的、卡哈尔间质细胞样的前体细胞。     

胸膜外孤立性纤维性肿瘤44例临床病理特征分析

目的:探讨胸膜外孤立性纤维性肿瘤(extrapleural solitary fibrous tumor,ESFT)的临床病理特征、鉴别诊断及预后。方法:对44例ESFT病例行病理学观察及免疫组化染色,结合临床及随访资料进行分析。结果:良性35例,恶性9例。ESFT组织学形态多样,典型者见梭形细胞呈无模式(patternless)排列,伴有粗大瘢痕样的胶原及血管外皮瘤样结构。免疫组化染色Vimentin、CD34、Bcl-2、CD99、SMA阳性率分别为100%、93%、79%、67%和6%,Desmin、S-100、CD117、Calretinin及EMA均为阴性。随访33例,3例局部复发,无死亡及远处转移。结论:临床病理特征和免疫组化表型有助于ESFT诊断及鉴别诊断。对ESFT患者有必要进行术后长期随访。     

孤立性纤维性肿瘤6例临床病理分析

目的探讨孤立性纤维性肿瘤（SFT）的临床及病理形态特征及免疫组化特点。方法结合文献对6例孤立性纤维性肿瘤的组织学、免疫组化特点进行分析。结果患者年龄37～65岁,平均50.1岁,病程2个月～2年,临床表现主要为局部肿块及压迫症状,肿瘤直径为3.0～5.0cm。免疫组化结果：CD34阳性6例,bcl-2阳性6例,Vim阳性6例,CD99阳性5例,desmin阳性2例,FVIII均阴性。结论SFT的临床诊断应结合临床特点、组织学形态、免疫组化特点综合考虑,其组织学构像并不能准确地判断其预后,患者术后的定期随访是必要的。     

Hemangiopericytoma/Solitary fibrous tumor of the oral cavity

Hemangiopericytoma/solitary fibrous tumor is a very rare tumor of uncertain malignant potential. About 300 such cases have been reported since 1942, when Stout and Murray described these tumors as "vascular tumors arising from Zimmerman's pericytes". Under the World Health Organization (WHO) classification, hemangiopericytomas and solitary fibrous tumors of the soft tissues are regarded as features of the same entity in the soft tissue fascicle. We report the case of a 54-year-old woman who presented with a painless right-side cheek mass of 2 cm maximum diameter. The lesion was completely removed by wide surgical resection. Histologically, the tumour had staghorn-like vasculature and immunohistochemistry for Calponin, CD68 KP1, AE1-AE3, smooth muscle actin and P63, S-100 was negative; that for CD34 was positive. A diagnosis of hemangiopericytoma/solitary fibrous tumor was rendered. The patient had a normal postoperative course of healing, and 24 months later remains asymptomatic, without signs of recurrence or metastasis. Because of the rarity and unpredictable biological behavior of these tumors, long-term follow-up is necessary even after radical resection because recurrence or development of metastasis may be delayed by many years.     

胃肠道及胃肠道外间质瘤的临床病理及免疫组化分析

目的:研究胃肠道及胃肠道外间质瘤的临床病理及免疫组化特点。方法:应用光学显微镜观察20例胃肠道及胃肠道外间质瘤的形态特征,用免疫组化SP法检测CD117、CD34、Vimentin、SMA、desmin及S-100等6种抗体的表达情况。结果:20例间质瘤中,女性11例,男性9例,平均年龄59·82岁(27~80岁)。发生部位:胃8例(40%),小肠4例(20%),大肠2例(10%),食管1例(5%),肠系膜4例(20%),大网膜1例(5%)。肿瘤镜下主要由梭形和上皮样细胞组成,有栅栏状、交叉束状、漩涡状及巢状等多种排列。CD117、CD34、Vimentin、SMA、desmin及S-100表达阳性率分别为95%(19/20),75%(15/20),100%(20/20),40%(8/20),5%(1/20)及25%(5/20)。临床症状以腹部包块、腹部不适及消化道出血为主。良性3例(3/20),潜在恶性4例(4/20),恶性13例(13/20)。恶性间质瘤中的核分裂>5/50HPF、肿瘤细胞坏死及细胞密集比良性和低度恶性者常见(P<0·05)。结论:间质瘤多发生于老年人,无性别差异,胃肠道是其好发部位,细胞排列多样,具有多向分化能力,免疫组化证实部分GIST具有不完全的平滑肌、神经单向或双向分化特征。核分裂>5/50HPF、肿瘤细胞坏死及细胞密集是重要的恶性指征。CD117及CD34是其较特异及敏感的抗体,免疫组化在间质瘤的诊断及鉴别诊断中起重要作用。     

Participation of alpha-smooth muscle actin-positive cells in renomedullary interstitial cell tumors

Renomedullary interstitial cell tumors are benign lesions which are generally discovered in specimens nephrectomized for other malignant tumors or by autopsy. We examined the histologic features of eight tumors from four patients and investigated the appearance of alpha-smooth muscle actin (ASMA)-positive cells in these tumors using immunohistochemistry. We considered that five tumors are cellular type and the remaining three as fibrous. Characteristic hyalinization was observed in two of the three fibrous tumors. All the tumors except for one fibrous type contained entrapped tubular cells. CD35-positive cells (dendritic cells) and ASMA-positive cells were observed in all the tumors, with a more frequent occurrence in the cellular type than the fibrous type. CD35-negative spindle cells were considered as fibroblasts or activated fibroblasts (myofibroblasts). The number of CD35-positive cells was higher than that of ASMA-positive cells. Additionally, the entrapped tubular cells showed the transition to spindle cells and some of them expressed for ASMA. With double immunohistochemical staining, there were some cells showing positive reactions for both CD35 and ASMA. Furthermore, an ultrastructural examination confirmed the presence of ASMA-positive filaments in the dendritic cells and myofibroblasts. The expression of TGF-beta 1 was observed not only in the tumor cells and the collecting ducts surrounding the tumor but also in the entrapped tubular cells. In addition, the intensity of TGF-beta 1 was stronger in/around the tumor than in the areas distant from the tumor. The positive cells were more numerous in the cellular type than in the fibrous type. In conclusion, ASMA-positive cells appear in renomedullary interstitial cell tumors and some of the cells may originate in dendritic interstitial cells, fibroblasts including myofibroblasts, and entrapped tubular cells. Furthermore, TGF-beta 1 may contribute to the formation of fibrosis in the tumors.     

Leiomyosarcoma of bone. A clinicopathologic, immunohistochemical, and ultrastructural study of five cases.

The authors identified five leiomyosarcomas (LMS) in a review of 13 nonmatrix-producing spindle cell sarcomas of bone. Only two were initially recognized as LMS; the others had been diagnosed as malignant fibrous histiocytoma (two) and fibrosarcoma (one). The patients, four of whom were women, ranged in age from 32 to 70 years. Sites included proximal humerus (two), distal femur (two), and rib (one). All tumors presented with clinical and radiographic features consistent with a diagnosis of primary bone neoplasms, although one probably represented a solitary metastasis from a primary uterine LMS. Radiographs showed lytic bone destruction with a moth-eaten appearance, and three cases had soft tissue extension. Histologically, all tumors showed broad, interlacing fascicles of spindle cells with pleomorphic nuclei, frequent mitoses, and necrosis. Two cases had a focal storiform pattern and bizarre multinucleated cells, and two other cases had focally prominent osteoclast-like giant cells. Extensive immunoreactivity for muscle actin was seen in all cases and for desmin in three. In each case, electron microscopy showed definite smooth muscle differentiation including cytoplasmic filaments with densities. At this writing, two patients are free of disease (including the patient with a presumed metastasis), one is alive with locally recurrent disease, and two are dead of disease. Experience suggests that LMS of bone is a distinct clinicopathologic entity that may be more common than previously recognized. Application of immunohistochemistry and electron microscopy to nonmatrix-producing bone sarcomas should facilitate diagnosis of additional cases.     

The immunohistochemical characterization of sarcomatoid malignant mesothelioma of the pleura

The immunohistochemical characteristics of epithelioid malignant mesothelioma are well described. However, immunohistochemical analyses of sarcomatoid mesothelioma, the less common type, are limited and its distinction from other tumors of the chest wall, lung and pleura is often problematic. We evaluated 24 patients with pleural sarcomatoid mesothelioma who had surgery (12 extrapleural pneumonectomies, 9 pleurectomies and 3 large biopsies) between 1989 and 2005. Clinicopathologic features and demographic data were recorded. We describe immunohistochemical results for 10 antibodies: AE1/AE3, CAM5.2 and MNF-116 keratins, calretinin, WT-1 protein, bcl-2, CD34, desmin, D2-40 and podoplanin. The patients were 23 men and one woman with a median age at diagnosis of 64.7 years (range 47 to 76). Tumor cells were positive for the keratin proteins AE1/AE3 in 18/24 cases, CAM 5.2 in 23/24 cases and MNF-116 in 21/21 cases. Calretinin was positive in 6/24 cases, WT-1 (nuclear) in 8/24 cases, bcl-2 in 0/24 cases, CD34 in 0/24 cases, desmin in 0/24 cases, D2-40 in 24/24 cases and podoplanin in 24/24 cases. This panel of antibodies may be helpful in establishing a pathologic diagnosis of sarcomatoid mesothelioma. In our study, D2-40 and podoplanin are highly sensitive immunohistochemical markers for sarcomatoid mesothelioma. Additional studies are required to define their role in the differential diagnosis of other spindle cell tumors.     

Sarcomatoid renal tumors. Clinicopathologic correlation of three cases

The clinical, light and ultrastructural features of three renal neoplasms demonstrating a sarcomatous appearance on light microscopic examination are reported. At the time of radical nephrectomy, all three tumors displayed aggressive features with capsular invasion and either metastases or invasion of adjacent organs. Ultrastructural examination revealed epithelial features in a pure spindle cell tumor and in a malignant fibrous histiocytoma-like tumor (sarcomatoid renal carcinoma) and smooth muscle differentiation (leiomyosarcoma) in a lesion showing features of malignant fibrous histiocytoma. All three patients died from 1 to 9 months after nephrectomy. Renal tumors with a sarcomatous histologic appearance are aggressive neoplasms that cannot be classified accurately solely by employing light microscopic criteria.     

Immunocytochemical evaluation of primary human esophageal carcinomas and their xenografts for keratin, beta-chorionic gonadotropin, placental lactogen, alpha-fetoprotein, carcinoembryonic antigen, and nonspecific cross-reacting antigen

The unlabeled antibody peroxidase-antiperoxidase technique was used to examine esophageal neoplasms for the tumor markers beta-human chorionic gonadotropin, human placental lactogen (HPL), alpha-fetoprotein, carcinoembryonic antigen (CEA), and nonspecific cross-reacting antigen (NCA) before and after xenotransplantation to athymic nude mice. In addition, keratin was used as an epithelial cell marker. Immunoreactive beta-human chorionic gonadotropin was detected in four of seven primary tumors and in three of seven xenografts. Two of seven primary tumors contained HPL immunoreactive cells while four of seven tumor xenografts had HPL immunoreactivity. alpha-Fetoprotein was detected in two of seven primary tumors and in one of seven xenografts. NCA and CEA were detected in six of seven primary tumors and in all tumor xenografts. Five of seven primary neoplasms and six of seven tumor xenografts were found to contain both NCA and CEA, while one tumor and its xenografts displayed only NCA immunoreactivity. All seven primary carcinomas displayed keratin immunoreactivity, but only six of the seven xenograft tumors showed keratin positive cells. When a tumor marker was detected in a primary tumor, it was usually found in at least some of the xenografts arising from that tumor. However, marker loss did occur with repeated passage of tumors in some cases. On the other hand, markers were expressed in xenografts which were not present in the corresponding primary tumor. In three instances, HPL was detected in xenografts derived from HPL negative primary carcinomas. This was also true for CEA and NCA in one case. These results show that tumor markers are expressed to varying degrees by tumors growing as xenografts in nude mice. In primary tumors, HPL is associated with poorly differentiated squamous cell carcinomas and this marker was found to appear in HPL negative tumors as the tumor cells became less differentiated while growing as xenografts in nude mice.     

Cytologic and histological features of rare nonepithelial and nonlymphoid tumors of the thyroid

Thyroid tumors can be classified into epithelial, nonepithelial, and nonprimary lesions. Nonepithelial thyroid tumors are rare. They can be of primary origin within the thyroid gland, arise secondary to contiguous growth from adjacent tissues, or represent metastatic disease. The incidence of nonepithelial tumors of the thyroid is only 1% to 2%, most of which are lymphomas; the remainder includes mesenchymal and histiocytic tumors. This review examines the cytohistological features of various nonepithelial and nonlymphoid tumors of the thyroid, including vascular lesions, neural tumors (including granular cell tumor and paraganglioma), smooth muscle tumors, solitary fibrous tumor, histiocytic neoplasms (eg, Langerhans cell histiocytosis and Rosai-Dorfman disease), and follicular dendritic cell sarcoma. Their differential diagnosis is discussed, including recommendations to prevent the pitfall of mistaking these rare tumors for more common epithelial thyroid neoplasms.     

Mohs surgery report: spindle cell fibrohistiocytic tumors: classification and pathophysiology

Four patients with spindle cell cutaneous fibrohistiocytic neoplasms are presented. A classification scheme for this group of tumors is discussed along with the histologic and immunohistochemical criteria needed to establish the diagnosis. Cutaneous malignant fibrous histiocytoma (atypical fibroxanthoma) may behave biologically as a neoplastic rather than reactive mesenchymal tumor with definite invasive and metastatic potential.     

42例胃肠道间质肿瘤的临床病理形态观察

目的：研究国人胃肠道间质肿瘤（gastrointe stinal stromal tumor，GIST）的临床病理形态特点。方法：应用光镜观察42例GIST的形态特征，用免疫组化S-P法检测CD117、CD34、SMA及S-100蛋白在GIST中的表达情况。结果：GIST的瘤细胞排列成交织束状、弥散片状、栅栏状或轮辐状，较为特征的是细胞团巢形成；胞质嗜酸性较经典的平滑肌瘤者为弱。瘤细胞为梭形或上皮样，或梭形与上皮样细胞混合存在。CD117和CD34的阳性率为92．9％（39／42）和76．2％（32／42）。结论：GIST是胃肠道最常见的间叶性肿瘤，有较为独特的组织学形态，CD117和CD34标记阳性是确诊GIST最有价值的诊断依据。