Frequent expression of bcl-2 protein in solitary fibrous tumors

The distinction of solitary fibrous tumors from histologically similar neoplasms is often difficult because they rarely occur at a variety of extrapleural sites. CD34 immunoreactivity has recently been recognized to be an adjunct for the diagnosis of solitary fibrous tumors. However, it is now known that CD34 staining is not entirely specific for this entity. We evaluated 23 solitary fibrous tumors and 54 other spindle cell tumors often considered in the differential diagnosis for immunoreactivity using monoclonal antibodies directed against bcl-2 protein, which protects cells from apoptosis and CD34. The patients with solitary fibrous tumors comprised 11 men and 12 women, ranging in age from 35 to 85 years (mean, 57.6 years). Fourteen tumors arose in the pleura, four in the retroperitoneum, three in the superficial soft tissue and one each in the mediastinum and uterine cervix. Nineteen of 23 solitary fibrous tumors (83%), irrespective of tumor site, demonstrated diffuse cytoplasmic staining for bcl-2 protein. bcl-2 immunoreactivity was also observed in five of seven neurofibromas (71%), eight of 10 synovial sarcomas (80%) and one of three spindle cell lipomas (33%). CD34 immunoreactivity was present in all but one solitary fibrous tumor (96%), seven of seven neurofibromas (100%), three of three spindle cell lipomas (100%), five of five dermatofibrosarcomas (100%), three of three hemangiopericytomas (100%) and two of seven malignant fibrous histiocytomas (29%). To date, most of the pleural and extrapleural cases have not shown aggressive features. We suggest that bcl-2 protein can be used together with CD34 in the diagnosis of solitary fibrous tumor to distinguish this entity from other spindle cell neoplasms.      

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。     

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.     

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.     

胰腺恶性孤立性纤维性肿瘤1例并文献复习

目的:讨论孤立性纤维性肿瘤（solitary fibrous tumor,SFT）的临床特征、病理学表现、影像学表现、诊断方法、鉴别诊断、治疗及预后,以提高临床医生对此病的认识及诊治水平。方法:报道1例术后肿瘤2次复发的胰腺恶性SFT的临床病理资料并文献复习。结果:患者女性,59岁,以“体检发现胰尾部肿物10天”为主诉首次入院,入院后诊断为胰体部占位,行胰体尾切除、脾切除术,术后石蜡病理提示胰体尾交界性梭形细胞肿瘤,考虑孤立性纤维性肿瘤。术后5月余复查,肿瘤复发于左上腹网膜囊内,再次手术切除复发肿物,术后石蜡病理提示交界性或低度恶性孤立性纤维性肿瘤。距二次术后4月余复查,肿瘤再次复发于左上腹网膜囊内,再次予手术切除肿物,术后石蜡病理提示交界性或低度恶性孤立性纤维性肿瘤。结论:胰腺恶性SFT病例极其罕见,术后复发者更是少之又少,确诊主要依靠病理组织形态学及免疫组化标记,并与其他相关性疾病加以鉴别,治疗方法以手术完全切除肿物为主,注意定期复查及远期随访。     

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.     

肾脏巨大恶性孤立性纤维瘤的临床病理分析

目的探讨肾恶性孤立性纤维瘤的临床病理学特征以及鉴别诊断。方法对1例肾恶性孤立性纤维瘤进行大体及镜下观察,并作免疫组织化学染色,结合文献进行复习。结果肉眼检查,肾脏被巨大肿块所取代,大小20cm×12cm×9cm,界限尚清,切面灰白灰黄色,可见多灶状坏死及直径0.6~1cm的小囊腔,质地细腻、软而脆。镜下表现为细胞稀疏区与密集区交错分布,梭形瘤细胞密集区排列成束状,束与束相互交错;疏松区间质黏液变性;细胞间有纤细至短束的胶原纤维;细胞核有轻 中度异型性,核分裂相4~6个/HPF,有多灶状肿瘤性坏死;无明显的血管外皮瘤样结构;可见到脂肪细胞化生及囊性变。免疫组织化学染色,瘤细胞Vimentin、CD99、Bcl-2弥漫阳性,CD34部分阳性,S100小灶状阳性。结论肾恶性孤立性纤维瘤非常少见,肿瘤体积大于10cm提示对恶性判断有参考意义;需与其他恶性梭形细胞肿瘤进行鉴别诊断。病理形态学特点及免疫组织化学染色可有助于鉴别。     

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.     

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.      

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.     

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.     

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.     

Solitary fibrous tumor of the oral mucosa--morphological and immunohistochemical profile in the differential diagnosis with hemangiopericytoma

The objective was to investigate two cases of solitary fibrous tumor (SFT) of oral mucosa, emphasizing the differential diagnosis with one case of oral hemangiopericytoma (HPC), in terms of their morphological and immunohistochemical features. Solitary fibrous tumors showed cellularity and collagenization varying from area to area, focal perivascular hyalinization, scattered giant nuclei cells and abundant mast cells throughout the tumor. The hemangiopericytoma case exhibited thin-walled and dilated vessels lined with flat endothelial cells, identified by "staghorn appearance". Tumoral cells of solitary fibrous tumor exhibited immunohistochemical positivity for CD34, as well as endothelial cells. The hemangiopericytoma was positive only in endothelial cells. In solitary fibrous tumor, alpha-smooth muscle actin, h-caldesmon and laminin stained the wall vessels. In hemangiopericytoma, on the other hand, the wall vessels were positive only for laminin, which staining was also observed in perivascular tumoral cells. The morphological and immunohistochemical differences observed allowed us to infer these lesions constitute distinct entities.     

A fibrotic nodule arising from the cerebellopontine angle

The authors present an extremely rare case of a fibrotic nodule arising from the cerebellopontine (CP) angle. A 57-year-old male had suffered from hearing disturbance and tinnitus for several years. Computed tomography revealed a high-density mass in the left CP angle with little enhancement after intravenous administration of contrast media. Magnetic resonance imaging (MRI) showed a very hypointense mass on T2-weighted imaging. T1-weighted MRI with gadolinium revealed very faint, delayed enhancement of the tumor. The patient underwent surgical resection of the tumor. Histopathologically the lesion comprised entirely fibrotic tissue consisting of thick collagenous fibers and sclerosing blood vessels with a few intervening viable cells with, partly, the immunophenotype of arachnoid cells. Intracranial fibrotic nodules are extremely rare. This tumor, however, had some radiological features similar to those of other, more common, tumors for example meningiomas or solitary fibrous tumors; it was, therefore, difficult to distinguish it from the others. It is believed that intracranial fibrotic nodules usually have benign, non-neoplastic characteristics, although their natural history is not yet fully understood. It is, therefore, necessary to be able to perform a differential diagnosis that will distinguish this rare condition from other intracranial fibrous neoplasms that occasionally have malignant features.     

眼眶恶性孤立性纤维性肿瘤的临床病理分析并文献复习

目的 探讨眼眶恶性孤立性纤维性肿瘤(malignant solitary fibrous tumor,MSFT)的临床病理特点及鉴别诊断.方法 对1例眼眶MSFT的临床表现、影像学、病理组织学变化及免疫表型进行分析,并结合相关文献进行讨论.结果 肿瘤细胞弥漫分布,主要由梭形细胞构成,呈束状、波浪状、席纹状等不规则排列,其中散在畸形或多核瘤巨细胞,核分裂像易见;间质血管丰富,主要为薄壁分枝状鹿角样小血管,局部包膜侵犯.免疫组化染色显示肿瘤细胞表达CD34、Bcl-2和Vimentin,CD68、S-100、SMA、CD117、F8、Melan A、HMB45、CD31均阴性.结论 发生于眼眶的MSFT是1种非常罕见的肿瘤,其临床表现及影像学均无特征性,明确诊断主要依靠病理组织学特征及免疫表型.     

Management of anterior mediastinal tumors

The most common neoplasms of the anterior mediastinum are thymomas, lymphomas, and germ cell tumors. Surgical exploration was the routine approach to the diagnosis and management of these tumors. This is no longer true. The appropriate initial treatment of these neoplasms varies from surgical resection to radiation therapy to systemic chemotherapy. Except for the small well-encapsulated anterior mediastinal mass, it is imperative that a definitive tissue diagnosis be obtained before initiating treatment. An overview of these tumors and the specific approaches to their treatment are detailed.     

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.     

Primary neuroendocrine carcinoma of the mediastinum

A mediastinal mass was found in a 37 year old male who presented with fever, weight loss and fatigue. The chest CT revealed a 9x6x4 cm well circumscribed mass located paratrachaelly in the upper mid-mediastinum. The mass was removed by right thoracotomy. Macroscopically the tumor weighed 195 g and measured 9x6x4 cm. Microscopically the tumor consisted of small blue cells in solid and trabecular pattern. Immunohistochemical studies performed for differential diagnosis of small blue cell tumors. The tumor was diagnosed as primary neuroendocrine carcinoma of the mediastinum. This case is presented for its rare recurrence in that particular location.     

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。