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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glomus tumors are benign lesions composed of vessels and glomocytes in varying proportions. The histological appearance of the tumors depend upon the ratio of the vascular to the glomus cells and their differentiation as well as upon the amount and composition of the stroma. The aim of the present study was the establishment of criteria for the distinction of glomus tumor-like malformations from neoplasms with glomus cell differentiation. Using a panel of monoclonal and polyclonal antibodies (vimentin, a-smooth muscle actin, desmin, pan-keratin, low molecular weight cytokeratin, EMA, NSE, S-100 protein, Factor VIII, a1-ACT) glomus tumors could be separated into three types: vascular, cellular with myxoid stroma and cellular, solid type. In the first two types the tumor growth is composed of all three components found in normal glomus body, but in a haphazard fashion and thus might be considered as tumor-like malformations. The third type is composed of perivascular arranged cells most of which acquire the phenotypical characteristics of glomocytes. This last tumor probably represent the neoplastic variant of the group of lesions designated by the term glomus tumor.
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PMID:Glomus tumor. A histological, histochemical and immunohistochemical study of the various types. 806 87

Malignant myoepithelioma of the salivary gland is discussed in terms of its clinical behaviour, morphological features and the frequent pre-existence of a pleomorphic adenoma. The study comprised six female and four male patients aged 14-63 years (mean age 38.9 years). Two tumours presented as intraoral lesions and eight were located in the parotid gland. Tumour cells displayed a morphological spectrum ranging from round epithelioid cells to spindle-shaped and stellate cells. Most cells displayed reactivity for high molecular weight keratins and in four tumours there was strong immunoreactivity for smooth muscle actin. Malignant myoepithelioma seems to arise in two different clinical settings: either de novo or in a recurrent pleomorphic adenoma. De novo malignant myoepitheliomas arise in normal salivary gland, tend to be more aggressive and have a short clinical history. Recurrences may not develop or may occur as a single event within a short time interval, and metastases develop in the lungs. Malignant myoepitheliomas arising in recurrent pleomorphic adenomas have a long clinical history, are characterized by multiple recurrences and have to be distinguished from aggressive carcinomas arising in these adenomas. In contrast, the tumours described in the present series arising in pleomorphic adenomas showed local aggressiveness and metastases did not occur until decades after the first treatment. The general opinion that all malignant tumours that arise from pleomorphic adenomas are highly aggressive is not confirmed by the present study.
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PMID:Malignant myoepithelioma of salivary glands: clinicopathological features of ten cases. 811 28

Surgical submissions from canine splenectomy cases spanning a 3-year period (1988-1990) were evaluated. Eighty seven neoplasms of the spleen considered to be of nonangiomatous and nonlymphomatous origin were selected for morphologic classification, mitotic index determination, immunohistochemical analysis, and patient survival determination. In 76/87 cases, patient survival information was available, and the mitotic index was determined in 83/87 cases. Immunohistochemistry for selected antigens (vimentin, desmin, smooth muscle actin, myosin, and factor VIII-related antigen) was performed in 58/87 of the cases. Morphologic classification of these lesions in standard HE preparations yielded the following neoplastic groups: fibrosarcoma (19/87), undifferentiated sarcoma (19/87), leiomyosarcoma (14/87), osteosarcoma (8/87), mesenchymoma (7/87), myxosarcoma (6/87), histiocytic sarcoma (6/87), leiomyoma (3/87), lipoma-myelolipoma (2/87), liposarcoma (2/87), and malignant fibrous histiocytoma (1/87). A lack of distinct morphologic characteristics among many of the neoplasms that were classified as either fibrosarcoma, leiomyosarcoma, or undifferentiated sarcoma contrasted these groups with the relatively unambiguous features that distinguished the other sarcoma groups. Using immunohistochemical staining for muscle-specific antigens (desmin, smooth muscle actin, and myosin), specific staining often overlapped extensively within the neoplastic groups of fibrosarcomas, leiomyosarcomas, and undifferentiated sarcomas, suggesting either ambiguous morphologic findings or the possibility of a common histogenesis from smooth muscle trabeculae or a distinct population of splenic myofibroblasts. The biological behavior of all tumors examined could be placed into three categories of patient survival: (1) benign, noninvasive tumors (leiomyoma, lipoma) with prolonged survival intervals; (2) malignant tumors (fibrosarcoma, undifferentiated sarcoma, leiomyosarcoma, osteosarcoma, myxosarcoma, histiocytic sarcoma, and liposarcoma), showing severely truncated survival (median 4 months with 80-100% mortality after 12 months; and (3) intermediate survival periods (median 12 months with 50% 1 year survival) attributed to a single group of neoplasm, the mesenchymomas. The biological behavior of primary splenic nonangiomatous, nonlymphomatous sarcomas was most closely correlated with observed mitotic index. Splenic neoplasms of this type with a mitotic index < 9 showed significantly (P < 0.0001) longer survival intervals than those with an index > 9. With the exception of osteosarcoma, all anatomically defined tumor groups contained one or more specimens with a mitotic index < 9. The clinical prognosis given for splenic sarcomas should be modified according to the mitotic index as a predictive value for patient survival.
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PMID:Primary mesenchymal (nonangiomatous/nonlymphomatous) neoplasms occurring in the canine spleen: anatomic classification, immunohistochemistry, and mitotic activity correlated with patient survival. 814 Jul 24

We describe the pathological features of a case of laryngeal epithelioid leiomyoma (leiomyoblastoma) which, to our knowledge, is the second case to be reported in the world literature. A review of the literature confirmed that leiomyoma as such is a very rare neoplasm in the larynx, and only 33 cases have been previously reported. The neoplasm was located in the left vocal cord and consisted of mainly epithelioid, round or spindle-shaped cells, often with clear cytoplasm, which were arranged predominantly in solid nests and sheets. The tumour cells showed positive immunoreactivity for smooth muscle actin and desmin. The tumour showed low mitotic activity and immunostaining with MIB 1 (Ki-67) accordingly revealed the occasional cell only to be positive, confirming a low proliferative activity in agreement with a benign neoplasm. Epithelioid leiomyomas located in other sites have been shown to act occasionally in a malignant fashion, and the necessity for careful long-term follow-up of the patient is therefore emphasized.
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PMID:Epithelioid leiomyoma of the larynx. 818 9

The cytologic features of a fine needle aspiration biopsy of a malignant intraductal myoepithelioma of the breast are described. On cytology the tumor cells were shed in cohesive groups consisting of ill-defined polygonal and spindle cells. The latter, which had centrally located, cigar-shaped nuclei, showed a fascicular pattern. Despite cellular multilayering, there was a halo-like transparency around the nuclei, suggesting that many cells had clear or pale cytoplasm. Mild nuclear atypia was occasionally present. Mitotic figures were also observed. With immunostaining, clustered cells showed a diffuse positive reaction for alpha smooth muscle actin (alpha-SM-actin). The tumor cells proliferated intraductally, as in a conventional intraductal carcinoma with a comedo or solid pattern. Characteristically, zones of clear, polygonal cells were situated at the ductal periphery. Toward the center of each duct, tumor cells were transformed into nonclear cells, and some were further transformed into spindle cells that tended to form fascicles. Immunohistochemically, most of the tumor cells expressed alpha-SM-actin.
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PMID:Aspiration cytology of malignant intraductal myoepithelioma of the breast. A case report. 819 38

Leiomyosarcoma in childhood is very rare. This report describes the immunohistochemical study of a gastric epithelioid leiomyosarcoma in a 14 year old girl. Microscopically, the tumor showed two distinct histological patterns within the same tumor: small epithelioid cells forming a lobular pattern and spindle-shaped cells forming interlacing fascicles, but no distinct border divided the two types of cells. Immunohistochemically, vimentin was positive in all tumor cells; alpha-smooth muscle actin, however, was negative in small epithelioid cells and positive in spindle-shaped cells. The data revealed that the tumor had components showing two stages of morphological and biochemical differentiation. This case indicates that leiomyosarcomas might lose smooth muscle actin during malignant transformation; or, alternatively, they might arise from a primitive type of smooth muscle cell and some of them could spontaneously differentiate into mature smooth muscle cells, expressing this actin.
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PMID:Differential alpha-smooth muscle actin expression in a gastric epithelioid leiomyosarcoma in a 14 year old girl. 820 66

An intravenous glomus tumor occurring in a forearm vein is reported. The patient had a painful subcutaneous mass which was completely excised. This mass was a neoplasm which expanded the lumen of a vein and extended throughout its wall into the surrounding subcutaneous fat. The neoplasm consisted of sheets of rounded cells with a capillary stroma. The neoplastic cells were closely apposed to the capillary vessels and were positive for vimentin, smooth muscle actin and muscle specific actin. The cells were negative for desmin, factor VIII-related antigen, epithelial membrane antigen, cytokeratins, S-100 protein and chromogranin. This is the 2nd reported case of intravenous glomus tumor of the forearm. This unusual presentation may be due to intravascular extension by a cutaneous glomus tumor. The potential for intravascular growth by glomus tumor should be recognized by surgeons, dermatologists and pathologists.
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PMID:Intravenous glomus tumor of the forearm. 822 12

Renal myxomas are rare neoplasms. Seven cases have been reported, of which only two are convincingly diagnosed as myxoma; the remaining cases exhibit features of sarcoma, fibroepithelial polyp, or myxolipoma. We report two additional cases; one in a 52-year-old man and another in a 68-year-old woman. They were discovered incidentally by radiological examination. The resected kidney in both patients contained a well-demarcated gelatinous intraparenchymal tumor, which consisted of occasional slender spindle cells scattered in an abundant myxoid stroma, closely resembling myxomas of other sites. The tumor cells showed immunoreactivity for vimentin but not for S-100 protein, epithelial membrane antigen (EMA), CAM 5.2, HHF-35, or smooth muscle actin. Ultrastructural features were of fibroblast-like cells with an elaborate network of cytoplasmic processes. The differential diagnosis of myxoid tumors of the kidney includes myxoid variants of renal sarcomas and carcinomas, renomedullary interstitial cell tumors, and fibroepithelial polyps. It is important to recognize the existence of a renal myxoma, to avoid confusing this benign tumor with the malignant neoplasms with secondary myxoid features that may involve the kidney.
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PMID:Renal myxoma. A report of two cases and review of the literature. 829 57

Twenty-four fetal rhabdomyomas (FRMs) of the head and neck occurring in 16 male and seven female patients (sex unknown in one), ranging from 3 days to 58 years of age (median, 4.5 years) are reported. Ten patients (42%) were < or = 1 year old, six lesions (25%) were congenital, and 11 lesions (46%) occurred in patients > or = 15 years of age. The median tumor size was 3.0 cm (range, 1.0 to 12.5 cm). The FRMs presented as well-defined, solitary masses arising within the soft tissue or mucosa (2:1) of the head and neck. The median follow-up in 15 cases was 48 months (range, 2 months to 52 years) after diagnosis. With the exception of one patient with a local recurrence, all patients were either alive and well or dead of unrelated causes. Eight cases, regarded as "classic" FRM, consisted predominantly of bland, primitive spindled cells associated with delicate, elongated skeletal muscle cells reminiscent of fetal myotubules that were haphazardly arranged in an abundant fibromyxoid stroma. The remaining 16 cases, designated as "intermediate" FRM, displayed both a greater degree and a greater number of cells with skeletal muscle differentiation as well as a variety of distinctive cytologic and architectural features. These included the presence of large, ganglion cell-like rhabdomyoblasts with vesicular nuclei and prominent nucleoli, interlacing ribbon or strap-like rhabdomyoblasts with deeply acidophilic cytoplasm, broad bundles of more delicate spindled rhabdomyoblasts arranged in fascicles simulating smooth muscle, an occasional plexiform pattern with infiltration of adipose tissue and skeletal muscle, focal intimate association with peripheral nerves, and rare areas of fibroblastic proliferation. Mitoses were not found in 19 of the 24 FRM cases, but in five tumors there were 1 to 14 mitoses/50 high-power fields. Marked nuclear atypia, anaplasia, and a "cambium layer" were uniformly absent. The FRMs typically stained for myoglobin, desmin, and muscle-specific actin with focal or rare staining for vimentin, smooth muscle actin, S-100 protein, glial fibrillary acidic protein, and Leu-7. Cytokeratin, epithelial membrane antigen, and CD68 antigen (with KP1) were not detected. This study expands on previous reports of FRM and demonstrates that it has both a broader age range and histologic spectrum than previously recognized. The mitotic rates of FRM as well as certain histologic features overlap with rhabdomyosarcoma; the lack of marked nuclear atypia is an important distinguishing feature.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Fetal rhabdomyoma of the head and neck: a clinicopathologic and immunophenotypic study of 24 cases. 831 54

A primary leiomyosarcoma of the thyroid was seen in a 54 yr old female. The patient had a solitary, cold nodule with no abnormalities of thyroid function tests. Histologically it was composed of characteristic interlacing fascicles of spindle cells which, electron microscopically, showed thin myofilaments with focal dense bodies. Immunohistochemistry showed a strong reaction with vimentin, smooth muscle actin and desmin. No epithelial differentiation was noted immunohistochemically or ultrastructurally. No tumor recurrence was detected 15 mths after surgery. It is postulated that the smooth muscle differentiation had arisen by metaplastic change or de-differentiation with re-differentiation of anaplastic thyroid carcinoma.
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PMID:Leiomyosarcoma of the thyroid: immunohistochemical and ultrastructural study. 836 5


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