1/23. Spindle epithelial tumor with thymus-like differentiation (SETTLE) of the thyroid with prominent mitotic activity and focal necrosis.Spindle epithelial tumor with thymus-like differentiation (SETTLE) is a rare, apparently low-grade spindle cell tumor of the thyroid gland occurring in young individuals and thought to be derived from thymic or branchial pouch remnants. Spindle epithelial tumor with thymus-like differentiation has little to no mitotic activity, and focal necrosis has been reported in one case. We present a case of SETTLE in a 29-year-old man that was initially evaluated by fine-needle aspirate biopsy and ultimately found to be consistent histologically with SETTLE. In this case, there were numerous mitotic figures among the spindle cells and focal necrosis. Spindle epithelial tumor with thymus-like differentiation has been considered to be a tumor of low malignant potential with metastases developing some years after diagnosis. This is the first case in which prominent mitotic activity and necrosis is reported perhaps representing an aggressive variant.- - - - - - - - - - ranking = 1keywords = spindle, spindle cell (Clic here for more details about this article) |
2/23. Primary invasive signet-ring cell melanoma.The histopathological variants of malignant melanoma include the common type (lentigo maligna, superficial spreading melanoma, nodular melanoma, acrolentiginous melanoma), spindle cell, desmoplastic, balloon cell, pleomorphic (fibrohistiocytic), myxoid, small cell melanoma and malignant blue nevus. Recently, signet-ring cell melanoma was introduced as an additional cytologic variant. We describe a 72-year-old patient with a primary signet-ring cell melanoma of the skin located on the upper arm. Histopathologic examination disclosed a melanocytic tumor extending from the epidermis to the deep reticular dermis. Numerous pleomorphic tumor cells showed large, intracellular vacuoles and oval to spindle-shaped nuclei at their periphery. Mitotic figures and multinucleated melanocytes were also observed. Some of the signet-ring cells exhibited cytoplasmatic periodic acid-Schiff (PAS)-positivity. immunohistochemistry showed positive reaction of the tumor cells for S-100, HMB-45 protein and vimentin, confirming their melanocytic differentiation. Tumor cells were negative for cytokeratins, epithelial membrane antigen (EMA), and carcinoembryonic antigen (CEA). The signet-ring cell melanoma disclosed an invasion to Clark Level IV and tumor thickness of 2.2 mm. Signet-ring cell melanoma is a rare morphologic variant of melanoma. Its recognition is important for differentiation from other tumors featuring signet ring cells.- - - - - - - - - - ranking = 0.81035901455386keywords = spindle, spindle cell (Clic here for more details about this article) |
3/23. Leiomyosarcomas of the oral cavity: an unusual topographic subset easily mistaken for nonmesenchymal tumours.AIMS: Oral leiomyosarcoma is rare and poorly documented. We aimed to characterize these lesions clinicopathologically in order to facilitate their distinction from other spindle cell neoplasms in the oral cavity. methods AND RESULTS: Ten cases of oral leiomyosarcoma were retrieved and studied histologically and immunohistochemically. Clinical data were obtained from referring pathologists and prior literature concerning 46 comparable cases was reviewed. Nine out of 10 cases occurred in adults; 50% arose in the jaws and four showed bone involvement. Histological appearances were similar to leiomyosarcomas elsewhere. In addition to myogenic markers, two cases were also keratin-positive. Four patients developed local recurrence or metastatic disease and three died of tumour (median follow-up 37 months). CONCLUSIONS: leiomyosarcoma is under-recognized in the mouth, often being mistaken for a spindle-celled epithelial neoplasm. Aside from an unusual but infrequent tendency to spread to lymph nodes and a location-specific differential diagnosis, its clinicopathological features are comparable to leiomyosarcomas at other locations.- - - - - - - - - - ranking = 0.81035901455386keywords = spindle, spindle cell (Clic here for more details about this article) |
4/23. Spindle epithelial tumor with thymus-like differentiation (SETTLE) of the thyroid.BACKGROUND: Tumors of the so-called intrathyroidal epithelial thymoma type are a rare group of thyroid neoplasm tumors. Of this type of tumor, spindle epithelial tumor with thymus like differentiation (SETTLE) has been reported only 17 times in English literature. methods: An 18-year-old woman was initially seen with a 6-cm left thyroid mass that was resected with a left thyroidectomy. Histopathologic features of the excised left thyroid tumor together with an immunohistochemistry and electron microscopy led us to a diagnosis of SETTLE. RESULTS: Most of the specimen was composed of highly cellular spindle cells that formed intersecting and streaming fascicles. The spindle cells showed both vimentin immunoreactivity and cytokeratin immunoreactivity but no immunoreactivity for thyroglobulin or calcitonin. Electron microscopic examination of the spindle cells demonstrated prominent cytoplasmic tonofilaments, desmosomes, and basal lamina consistent with epithelial cell origin. dna content analysis by flow cytometry revealed dna diploidy. CONCLUSIONS: SETTLE of thyroid gland is an extremely rare entity. A review of the literature reveals that SETTLE has distinctive morphologic features and an immunohistochemical profile.- - - - - - - - - - ranking = 1.8103590145539keywords = spindle, spindle cell (Clic here for more details about this article) |
5/23. Malignant peripheral nerve sheath tumor with divergent differentiation.Right posterior thigh malignant peripheral nerve sheath tumor with malignant glandular and rhabdomyoblastic components was diagnosed in a 24-year-old African American man. Malignant glands and rhabdomyoblastic cells were admixed with the spindle cells. immunohistochemistry demonstrated spindle cells positive for S100 and vimentin; the glandular component was positive for chromogranin, and rare cells were positive for CK20 but negative for CK7. Rhabdomyoblastic cells were positive for muscle-specific actin and desmin. A single pulmonary metastasis occurred 5 months after surgical resection of the tumor. death occurred 1 month later and was probably due to a pulmonary embolus.- - - - - - - - - - ranking = 1keywords = spindle, spindle cell (Clic here for more details about this article) |
6/23. Low-grade renal epithelial tumor originating from the distal nephron.There are few published reports of low-grade renal epithelial tumor originating from the distal nephron. However, it should not be disregarded clinically, because the actual number of patients with such tumors may be higher than expected. We investigated the immunohistochemical profile of a histologically distinct subtype of such a tumor in detail, in addition to the clinical course and imaging studies. The present study demonstrated that both glandular and spindle cell components of this tumor have a persistent characteristic of an epithelial tumor arising from the distal tubule or collecting duct. This tumor is a benign complex neoplasm that can be treated successfully with radical surgery. Beta-catenin and E-cadherin are suggested to play a crucial role in tumorigenesis and the biphasic arrangement of this neoplasm, concerning the expression of epithelial membrane antigen and carbohydrate antigen 19-9. We suggest that the term 'distal nephron epithelioma' is appropriate for classifying such rare but clinicopathologically distinct tumors.- - - - - - - - - - ranking = 0.5keywords = spindle, spindle cell (Clic here for more details about this article) |
7/23. Incidental stromal-predominant mixed epithelial-stromal tumors of the kidney: a mimic of intraparenchymal renal leiomyoma.CONTEXT: Mixed epithelial-stromal tumor of the kidney is a recently recognized benign renal tumor that usually occurs in adult women and typically forms a sizable lesion with solid and cystic areas. The recognized morphologic spectrum of this recently described entity is evolving. OBJECTIVE: To review the clinicopathologic features of 3 small mixed epithelial-stromal tumors of the kidney that were incidental findings in kidneys removed for other reasons. DESIGN: The clinical presentation and morphologic findings of the 3 cases were reviewed. A panel of immunohistochemical stains was performed. SETTING: Academic medical center. RESULTS: All 3 lesions contained predominantly fascicles of smooth muscle mimicking leiomyoma, but they also had cellular subpopulations of smaller, mullerian-appearing stromal cells. Tubules present within the lesion were most abundant at the periphery, suggesting that they might be entrapped. Although only the spindled smooth muscle cells were immunoreactive for muscle markers desmin and actin, both the spindled smooth muscle cells and the cellular mullerian-appearing stromal cells demonstrated diffuse nuclear labeling for estrogen and progesterone receptors. CONCLUSIONS: Mixed epithelial-stromal tumor of the kidney may present as an incidental stromal-predominant lesion within the kidney. Such lesions are easily confused with leiomyomas or stromal-predominant angiomyolipomas.- - - - - - - - - - ranking = 0.62071802910771keywords = spindle (Clic here for more details about this article) |
8/23. Mixed epithelial and stromal tumor of the kidney in a 12-year-old girl.Mixed epithelial and stromal tumor of the kidney (MESTK) is a rare kidney neoplasm that almost exclusively occurs in perimenopausal women, and long-term estrogen replacement is relevant to its pathogenesis. Herein is described an atypical case of MESTK uncovered in a 12-year-old premenarcheal girl without a history of prior estrogen use. On surgical specimen it was found that the well-circumscribed tumor measuring 14 cm arose from the lower pole of the right kidney, showing solid and fibrous-cystic areas. Microscopically, it was composed both of epithelial structures similar to renal tubules and stroma comprising non-specific spindle cells. Some intratumoral tubules showed affinities to distal-nephron-specific lectins, and those immunoreactive for proximal-tubule-specific CD15 were also present. In addition, primitive ductal structures were reactive both for CD15 and lectins, but immature epithelial elements typical of nephroblastoma were absent. Spindle cells were positive for actin, desmin and vimentin, and expressed progesterone and estrogen receptors. The tumor was comparable with MESTK, although some epithelia were associated with the immunophenotype of proximal tubules. The patient was free of disease postoperatively for 40 months. In the present case, remnants of the primitive periductal mesenchyme might be promoted to neoplastic cells by a sex-steroid surge during puberty.- - - - - - - - - - ranking = 0.5keywords = spindle, spindle cell (Clic here for more details about this article) |
9/23. Spindle epithelial tumor with thymus-like differentiation (SETTLE) of the thyroid with neck lymph node metastasis: a case report.Spindle epithelial tumor with thymus-like differentiation (SETTLE) is an extremely rare type of thyroid tumor. It has been reported only 20 times in the English literature. This tumor occurs predominantly in young patients and has a protracted clinical course despite the occurrence of metastases. In the recent literature SETTLE has been considered to be a tumor of low malignant potential with distant metastases developing some years after diagnosis. Herein we report a case of SETTLE in a 22-yr-old man in which a lymph node metastasis developed soon after the primary tumor manifestation. Histological examination of the tumor showed the predominantly monophasic variant of SETTLE. The primary and metastatic lesions were highly cellular tumors composed of sheets of spindle cells that were positive for pan-cytokeratin and vimentin and negative for thyroglobulin, calcitonin, and S-100 protein.- - - - - - - - - - ranking = 0.5keywords = spindle, spindle cell (Clic here for more details about this article) |
10/23. Early metastasizing spindle epithelial tumor with thymus-like differentiation (SETTLE) of the thyroid.Spindle epithelial tumor with thymus-like elements is a rare thyroid lesion of children and young adults thought to be derived from branchial pouch remnants or foci of ectopic thymus. The lesion is poorly understood, and although it was originally believed to follow an indolent clinical course, its potential for late metastasis is becoming generally acknowledged. We have recently seen a unique case of this rare tumor in an 11-year-old boy, in which an unexpected and salient feature is the presence of a micrometastasis in a single lymph node at presentation. With the exception of 1 case with extensively infiltrative tumor and metastatic disease at the time of onset, in all other cases dissemination occurred years after surgical resection of the primary lesion. We review all previously reported cases and provide a detailed study of the histologic and ultrastructural appearances of this lesion.- - - - - - - - - - ranking = 1.2414360582154keywords = spindle (Clic here for more details about this article) |
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