Teratoma of the Sellar Region: a Case Report

The case report describes a teratoma of the sellar region with a gland forming and an immature, relatively clear undifferentiated component without signs of anaplasia. Both components express TTF-1 indicating their presumable origin in the neurohypophysis as part of the circumventricular organs. The differential diagnosis includes pituitary adenoma and spindle cell oncocytoma with inclusion of Rathke’s cleft cyst, pituitary blastoma, yolk sac tumor, and other germ cell tumors. The prognosis is the same as in the immature teratomas in the gonads, specifically unclear.     

Sarcomatoid Renal Cell Carcinoma Metastatic to the Heart: Report of a Case

An unusual case of metastatic sarcomatoid renal cell carcinoma is presented. Fifteen months after nephrectomy for a typical clear cell carcinoma, a 63-year-old man presented with bilateral pleural effusions, cardiomegaly, and tamponade. A pericardial biopsy showed an anaplastic spindle cell tumor that was strongly keratin positive and showed desmosomes ultrastructurally. The patient died shortly thereafter, and the autopsy revealed massive tumor infiltration of the heart, pulmonary and adrenal metastases, and tumor nodules at the incision site of his nephrectomy. The differential diagnosis of sarcomatoid renal cell carcinoma is discussed.     

Sarcomatoid Renal Cell Carcinoma Metastatic to the Heart: Report of a Case

An unusual case of metastatic sarcomatoid renal cell carcinoma is presented. Fifteen months after nephrectomy for a typical clear cell carcinoma, a 63-year-old man presented with bilateral pleural effusions, cardiomegaly, and tamponade. A pericardial biopsy showed an anaplastic spindle cell tumor that was strongly keratin positive and showed desmosomes ultrastructurally. The patient died shortly thereafter, and the autopsy revealed massive tumor infiltration of the heart, pulmonary and adrenal metastases, and tumor nodules at the incision site of his nephrectomy. The differential diagnosis of sarcomatoid renal cell carcinoma is discussed.     

胸膜肺母细胞瘤1例报道及文献复习

目的：阐明胸膜肺母细胞瘤的病理形态特征及鉴别诊断要点。方法：对1例小儿胸膜肺母细胞瘤进行了组织形态学,免疫组织化学分析。结果：胸膜肺母细胞瘤是一种纯间质性恶性肿瘤,好发于12岁以下的儿童及婴幼儿,起源于肺、胸膜或纵隔的原始细胞,镜下可见原始胚胎性的圆形或短梭形细胞,瘤细胞有呈巢趋势,酷似肾母细胞瘤,肝母细胞瘤等肿瘤原始胚基成分,免疫组化未见有上皮细胞及其他间叶成分标志的表达,另一种成分为梭形细胞,除表现为纤维肉瘤特点外,还向横纹肌肉瘤分化,结论：胸膜肺母细胞瘤是一种极为罕见的恶性肿瘤,应与肺母细胞瘤,原始神经外胚叶肿瘤及胚胎性横纹肌肉瘤等鉴别。     

Benign spindle cell tumors of the mammary stroma: diagnostic criteria, classification, and histogenesis

Purely benign mesenchymal spindle cell neoplasms of the breast are currently labeled under various terms in the literature (benign spindle cell tumor, fibroma, spindle cell lipoma, myofibroblastoma, solitary fibrous tumor, myogenic stromal tumor). The lack of strict diagnostic criteria to clearly indicate such mesenchymal neoplasms is the main reason which generated the risk of terming the same lesion under different names or, conversely, of collecting different types under the same term. Although such neoplasms exhibit morphological and immunophenotypical heterogeneity, they actually represent variations of the same tumor entity, likely arising from the uncommitted vimentin+/CD34+ fibroblasts of the mammary stroma, capable of multidirectional mesenchymal differentiation. To cover the entire spectrum of such lesions, the term "benign spindle cell tumors (BSCTs) of the mammary stroma" is advocated. BSCTs can be subtyped into four main groups by light microscopy (LM) and immunocytochemistry (ICC): fibroblastic, myofibroblastic, fibrohistiocytic, and mixed forms. A simple and practical approach to a nosologically correct diagnosis and a list of differential diagnoses are presented. The awareness of the diversity of morphological and immunophenotypical features of BSCTs of the mammary stroma, including uncommon variants, is helpful to avoid confusion with other monomorphic bland-looking benign and malignant spindle cell tumors and tumor-like lesions of the breast.     

A Case of Adenocarcinoma of the Lung with a Spindle Cell Component

We report a 60-year old man, who was admitted to the hospital with complaints of cough and sputum. His chest x-ray showed an abnormal mass in the right upper lobe. After admission he noticed the painful gingival tumor. Right upper lobectomy and resection of the gingival tumor were performed. Their histological features showed that the tumor consisted of a papillary and tubular adenocarcinoma mixed with a component of spindle cells. Immuno-histochemical study demonstrated a positive reaction in the epithelial component for keratin and epithelial membrane antigen, and not only these epithelial markers but also vimentin were expressed in some spindle tumor cells. Electron microscopic study confirmed the biphasic pattern, showing gland formation and undifferentiated cells. We diagnose this case as adenocarcinoma of the lung with a spindle cell component and the gingival tumor was meta-static. Autopsy showed that metastatic lesions were found in the left adrenal gland and in the left kidney. The tumor cells in the left adrenal gland were composed of spindle cells and the tumor in the left kidney showed gland formation. lmmunohistochemical and electron microscopic findings of surgical and autopsy specimen suggest that this tumor is of epithelial origin, and the spindle cells are derived from immature mesenchymal cell transformation of epithelial cells. Acta Pathol Jpn 42: 841–846, 1992.     

Dendritic fibromyxolipoma: A variant of spindle cell lipoma with extensive myxoid change,with cytogenetic evidence

Dendritic fibromyxolipoma (DFML), a rare, recently described distinct benign soft tissue tumor, has many clinicopathological features reminiscent of spindle cell lipoma and solitary fibrous tumor with myxoid change. It is distinguished histologically from both entities by the presence of spindle and stellate cells with dendritic cytoplasmic prolongations, prominent myxoid stroma with abundant keloidal collagen and occasional small plexiform vascular proliferation. We describe a case of histologically confirmed DFML of the left shoulder in a 67‐year‐old male, in which subsequent cytogenetic analysis revealed deletion involving 13q14.3 region in all the tumor cells, typically detected in spindle cell lipoma. In the presence of many clinicopathological similarities between DFML and spindle cell lipoma including chromosomal abnormalities, we postulate that DFML is merely a rare variant of spindle cell lipoma with extensive myxoid degeneration, and may not be considered as a separate entity. The possible differential diagnosis and their distinguishing features are briefly discussed.     

Cytologic diagnostic pitfall of dermatofibrosarcoma protuberans masquerading as primary parotid tumor: A case report

We report the cytology of a rare case of dermatofibrosarcoma protuberans (DFSP) involving the parotid region. Our patient was a 55‐year‐old female who presented with a swelling in the right parotid region, which was clinically interpreted as a “recurrent parotid tumor.” Fine needle aspiration revealed a moderate cellular yield with spindle cell component, seen discretely as well as, embedded loosely within a fibrillary magenta matrix. A few cellular spindle cell fascicles and several discrete, naked, spindly nuclei were also noted. Neoplastic cells exhibited a minimal pleomorphism with a relatively bland chromatin and inconspicuous nucleoli. A differential diagnosis of the benign spindle cell tumor/low, or intermediate grade myxoid, spindle cell sarcomas was considered. Owing to its clinical presentation simulating a parotid tumor, possibility of “spindle cell myoepithelioma” was suggested. However, histopathologic examination with immunohistochemistry showed it to be a DFSP. A precise diagnosis of DFSP is not always possible on cytology alone. Owing to its location, as well as the spindle cell morphology, DFSP occurring in the parotid region is likely to be mistaken for a spindle cell myoepithelioma, in which case, an appropriate panel of immunomarkers is required for resolving the diagnostic dilemma. Diagn. Cytopathol. 2009. © 2009 Wiley‐Liss, Inc.     

The evolution of collagen expression in sarcomatoid renal cell carcinoma

The development of a sarcomatoid morphotype is recognized as an extreme form of dedifferentiation in renal cell carcinoma and is associated with a poor prognosis. Although sarcomatoid renal cell carcinoma shows pronounced spindle cell morphology, clear cell renal cell carcinoma may show early spindle cell change with cellular elongation, and the prognostic significance of this is debated. To determine the relationship between sarcomatoid renal cell carcinoma and clear cell renal cell carcinoma showing early spindle cell change, we have investigated collagen expression using immunohistochemistry in these 2 tumor types. Both sarcomatoid renal cell carcinoma and early spindle cell change tumors showed pericellular interstitial expression of collagen types I and III, whereas sarcomatoid renal cell carcinoma also showed cytoplasmic expression of these collagen types. Expression of these collagen types in typical clear cell renal cell carcinoma was, in occasional cases, limited to faint and patchy staining in a pericellular interstitial distribution. Tumor cells did not stain for collagen type IV in sarcomatoid renal cell carcinoma, early spindle cell change, or typical clear cell renal cell carcinoma. In sarcomatoid renal cell carcinoma, there was diffuse pericellular expression of collagen type V and patchy pericellular expression of collagen type VI, whereas early spindle cell change tumors showed patchy pericellular staining with antibodies to collagen type V. Collagen type VI expression in early spindle cell change was largely confined to the vascular adventitia and areas of scarring, although very occasional foci of faint interstitial staining were also seen. In typical clear cell renal cell carcinoma, staining of collagen types V and VI was limited to the vascular adventitia and foci of desmoplasia, whereas no staining of tumor cell cytoplasm were seen. This study has shown that collagen expression of sarcomatoid renal cell carcinoma differs from that of early spindle cell change and provides validating evidence that these 2 morphotypes should not be considered together for classification purposes.     

Sarcomatoid carcinoma with small cell carcinoma component of the urinary bladder: a case report with review of the literature

Sarcomatoid carcinoma of the urinary bladder is an uncommon neoplasm characterized histopathologically by the presence of malignant spindle cell and epithelial components. Albeit extremely rare, sarcomatoid carcinoma with small cell carcinoma has been reported. Herein, we describe an additional case of sarcomatoid carcinoma with small cell carcinoma and squamous cell carcinoma of the urinary bladder and review the clinicopathological features of this type of tumor. An 82-year-old Japanese male presented with hematuria. Computed tomography demonstrated a large tumor in the urinary bladder. Histopathological study of the resected urinary bladder tumor showed that approximately 80% of the tumor was comprised of small cell carcinoma, and the remaining components were spindle cell proliferation (approximately 15%) and squamous cell carcinoma (5%). Both the spindle cell and squamous cell carcinoma components were intermingled with nests of the small cell carcinoma. This is the fifth documented case of sarcomatoid carcinoma with small cell carcinoma of the urinary bladder. Our review of the clinicopathological features of this type of tumor revealed that: i) elderly males are mainly affected, ii) the most common chief complaint is hematuria, iii) the epithelial component may include urothelial carcinoma, adenocarcinoma, and/or squamous cell carcinoma, and iv) the sarcomatous component is composed of spindle cell proliferation. The histogenesis of this type of tumor remains a matter of controversy. However, recent molecular analyses demonstrated a monoclonal origin of both components. This theory can account for the various types of carcinomatous components in this tumor as seen in the present case.     

Spindle cell carcinoma of the breast: A case report and an immunohistochemical study including p53 and Ki-67 expression

A rare case of spindle cell carcinoma (SpCC) of the breast occurring In a 51-yearold Japanese woman Is reported. A firm and well-circumscribed tumor, measuring 9times8.5times8.5 cm, was located on the upper lateral region of the right breast. Microscopically, the tumor consisted of sheets of both malignant spindle cells and poorly differentiated ductal carcinoma containing squamold islands with gradual transition to the spindle cell component. The Immunocyto chemical expression of epithelial markers was recognized in the spindle cells, as well as in the carcinomatous cells. Moreover, the spindle cell component expressed vimentin, α-smooth muscle actln and S-100 protein. Ultrastructurally, in addition to the features of adenocarcinoma, squamous or rnyoeptthelial differentiation was confirmed in the spindle cell component. These findings thus suggest an epithelial origin with squamous differentiations and myoepithellal participation In the genesis of SpCC. In a comparative study, the expression of p53 protein and KI-67 as a proliferation marker In each component of this tumor was also Investigated. The mean p53 labeling index (LI) in both the carcinomatous and spindle cell area was similar, however the mean MIB-1 LI in the spindle cell area was significantly higher than that in the carcinomatous area. The results indicate that p53 over-expression is Involved In the tumorigenesis of both components in the SpCC, and the spindle cell component shows a higher degree of proliferative activity than the carcinomatous component.     

Carcinosarcoma of the esophagus characterized by myoepithelial and ductal differentiations

We report a case of carcinosarcoma of the esophagus characterized by ductal and myoepithelial differentiation. A 61-year-old man was operated on for a polypoid tumor of the distal esophagus. Histologically, this tumor was composed of ductal structures and sarcomatous spindle cells surrounding the ducts at the central area of the tumor. The tumor was also composed of squamous cell and basaloid carcinoma in the periphery. Immunohistochemically, a few spindle cells surrounding the ductal structures showed immunopositivity for alpha-smooth muscle actin and S-100 protein. Electron microscopy revealed that the spindle cells had tonofilament and pinocytic vesicles in the cytoplasm, and basal lamina adjacent to the cytoplasmic membrane. Both of the results strongly supported the suggestion that the spindle cells may be myoepithelial cells. Basaloid carcinoma showed a gradual transition to chondrosarcomatous cells producing the matrix, which had both immunopositivities for S-100 protein and cytokeratin. Therefore, chondrosarcomatous cells may be derived from carcinoma cells. The histogenesis of this tumor may be associated with a totipotent stem cell of esophageal mucosa, which has the potential to differentiate into squamous cells, ductal cells or myoepithelial cells.     

Giant cell rich osteosarcoma of the mandible with abundant spindle cells and osteoclast-like giant cells mimicking malignancy in giant cell tumor

Giant cell rich osteosarcoma is a relatively unusual histological form of osteosarcoma, common lesion usually presenting in the long bones of the appendicular skeleton. The occurrence in the mandible is exceptional rare. Histologically, this tumor tends to be a highly anaplastic, pleomorphic tumor in which the tumor cells may be: plasmacytoid, fusiform, ovoid, small round cells, clear cells, mono-or multinucleated giant cells, or, spindle cells. Herein, we present a case with the sternum and first thoracic vertebra metastasis from primary giant cell rich osteosarcoma of the mandible in a 28 year-old Chinese female. The tumor was predominantly composed of abundant spindle cells with marked atypia and numerous osteoclast-like giant cells reminiscent of malignancy in giant cell tumor. The unusual histological appearance can pose a great diagnostic challenge. It may be easily misdiagnosed, especially if the specimen is limited or from fine-needle aspiration.     

Sarcomatoid intracardiac metastasis of a testicular germ cell tumor closely resembling primary cardiac sarcoma

This report describes a 40-year-old man with a remote history of testicular mixed nonseminomatous germ cell tumor (NSGCT) treated by surgery and chemotherapy. He presented 10 years later with shortness of breath and was found to have a mass occupying the right atrium, based high in the superior vena cava. He also had multiple pulmonary emboli. The sarcomatous and myxomatous histological appearance of the neoplasm closely resembled a primary cardiac sarcoma. However, immunohistochemical studies confirmed the diagnosis of metatstatic sarcomatoid germ cell tumor. Metastatic spindle cell tumors have been reported in patients with NSGCTs. These neoplasms are thought to arise from the spindle cell component of the yolk sac tumor that is resistant to chemotherapy.     

STAT6 expression in spindle cell lesions of the breast: An immunohistochemical study of 48 cases

The diagnosis of spindle cell lesions of the breast parenchyma is challenging. Some of these lesions share the expression of CD34, posing differential diagnostic problems, especially in core biopsies. Recently, antibodies against the STAT6 C-terminal, are being used in paraffin-embedded tissues as a surrogate for identifying the NAB2–STA6 fusion gene which is considered a specific molecular marker for solitary fibrous tumor. Accordingly, we investigated the expression of STAT6 in a large series of uncommon spindle cell tumor-like and tumor lesions occurring primarily in the breast parenchyma. We collected 10 classic-type myofibroblastomas, 9 desmoid-type fibromatosis, 6 spindle cell metaplastic carcinoma, 5 benign fibroblastic spindle cell tumors, 3 solitary fibrous tumors, 7 pseudoangiomatous stromal hyperplasias, 2 reactive spindle cell nodules, 1 leiomyoma, 1 spindle cell lipoma, 1 case of inflammatory pseudotumor, 1 nodular fasciitis, 1 myxoma and 1 dermatofibrosarcoma protuberans. A diffuse and strong nuclear STAT6 expression was restricted only to solitary fibrous tumors, while the other lesions were negative or showed only weak cytoplasmic expression. The present study confirms that the demonstration of a diffuse and strong STAT6 nuclear staining is very helpful in distinguishing solitary fibrous tumor from other spindle cell mimics arising in the breast.     

Laryngeal blastoma. A light and electron microscopic study of a novel entity analogous to pulmonary blastoma

A neoplasm morphologically analogous to pulmonary blastoma, but arising in the pyriform fossa of the larynx, is described and illustrated. The patient, a 65-year-old white man, was treated with laryngectomy and is alive and free of disease 13 months later. Grossly polypoid on a broad stalk, the neoplasm consisted of a mixture of blastematous, mesenchymal, and epithelial elements. Ultrastructural examination showed that the spindle and stellate cells were truly mesenchymal. The name "laryngeal blastoma" is proposed for this novel entity.     

Malignant peripheral nerve sheath tumor of small round cell type with pleomorphic spindle cell sarcomatous areas

An unusual case of malignant peripheral nerve sheath tumor (MPNST) arising in the posterior mediastinum of a 59-year-old man is reported. Histopathologically, the tumor showed an admixture of a dense proliferation of small round cells resembling a primitive neuroectodermal tumor (PNET) and a pleomorphic spindle cell sarcomatous area. Abortive rosettes, primitive neural tube-like structures, and a few glandular structures were found in the small round cell area. Small round cells were immunoreactive for neural cell adhesion molecule and synaptophysin, but were not immunoreactive for MIC2 and neuron-specific enolase. Pleomorphic spindle cells were occasionally arranged in a storiform pattern and were diffusely immunoreactive for S-100 protein. The MPNST of small round cell type is distinguishable from PNET by its negative immunoreactivity for MIC2, and the present tumor is assumed to be derived from primitive neuroectodermal cells in the peripheral nerve capable of bidirectional (neuron and Schwann cell) differentiation.     

Sarcomatoid neoplasms of the lung and pleura

Sarcomatoid neoplasms of the lung and pleura are rare tumors that present a complex differential diagnosis, making them challenging for surgical pathologists. In the lung, the main tumors are the sarcomatoid carcinomas, including pleomorphic carcinoma, spindle cell carcinoma, giant cell carcinoma, carcinosarcoma, and pulmonary blastoma. They are characterized by histologic heterogeneity; molecular data support their origin from a pluripotent stem cell that undergoes neoplastic transformation with divergent epithelial and sarcomatous differentiation. Diagnosis is difficult in small biopsy specimens and typically requires a resection specimen. Despite the presence of sarcomatoid features, these tumors are classified as lung carcinomas. Pulmonary blastomas must be distinguished from pleuropulmonary blastomas, which are a unique type of thoracic sarcoma typically occurring in young children. In the pleura, the main tumors to consider are the sarcomatoid and desmoplastic types of malignant mesothelioma, solitary fibrous tumor, and desmoid tumor. While light microscopy is sufficient to diagnose most of these tumors, immunohistochemistry can be useful in selected settings. In particular, it can aid to confirm epithelial differentiation in spindle cell carcinomas and the presence of rhabdomyosarcoma in sarcomatoid carcinomas, mesotheliomas, or pleuropulmonary blastomas. For sarcomatoid and desmoplastic mesothelioma, keratin is the most useful stain because it can highlight invasive growth and mesothelial markers are positive in only the minority of cases. Clinical and radiologic correlation is needed to separate some pleomorphic carcinomas with pleural involvement from sarcomatoid malignant mesothelioma, since these poorly differentiated tumors may not express the usual immunohistochemical markers for carcinoma or mesothelioma.     

Squamous cell carcinoma with sarcomatous feature (so-called carcinosarcoma) of stomach probably metastasized from esophageal tumor: a case report with quick-freezing and deep-etching method

A squamous cell carcinoma (SCC) with sarcomatous features (so-called carcinosarcoma) of stomach is reported in a 72-year-old man. The gastric submucosal tumor (12 × 11 × 6cm) consisted of carcinoma cells and sarcomatous spindle cells, which were immunohistochemically recognized to contain high molecular weight cytokeratin. These histological and immunohistochemical results indicated that carcinoma cells and spindle tumor cells had cytokeratin similar to that of stratified squamous epithelium. These features were consistent with so-called carcinosarcoma of esophagus. A combined type of tumor consisting of polypoid and shallow ulcerative lesions (5.5cm in diameter) was demonstrated by the biopsy to have SCC on the polypoid surface area. Therefore, the gastric tumor was thought to have metastasized from the esophageal tumor. The quick-freezing and deep-etching (QF-DE) method demonstrated that many spindle tumor cells in the gastric tumor had abundant intermediate filaments, which were evenly distributed in more peripheral cytoplasm along the cell membrane. This feature was similar to that of the control SCC. Intramembranous protein particles in the cell membrane of the tumor cells were markedly decreased as compared with those of control SCC. These ultrastructures by QF-DE method could be used for the pathological diagnosis of so-called carcinosarcomas of esophagus.