(1/107) Recurrent involvement of 2p23 in inflammatory myofibroblastic tumors.

Inflammatory myofibroblastic tumor (IMT) is a relatively rare soft tissue tumor. The reactive versus neoplastic pathogenesis of this tumor is unresolved. We found clonal chromosome aberrations involving 2p23 upon metaphase analysis of two IMTs. Fluorescence in situ hybridization with a probe flanking the ALK gene at 2p23 demonstrated rearrangement of the probe in both of these cases and in a third case, and immunohistochemistry revealed ALK expression in all three cases. 2p22-24 involvement has been reported previously in four additional cases of IMT. We suggest that chromosomal rearrangements involving 2p23 near or within ALK are recurrent alterations in IMT and that ALK may have a novel role outside its previously recognized realm of lymphoid neoplasms.  (+info)

(2/107) Cancers in children infected with the human immunodeficiency virus.

The AIDS epidemic continues unabated in Africa, Asia, and South America, and since patients survive longer, the number of chronically immunocompromised individuals is increasing in Europe and the United States. The number of children with HIV infection who will ultimately develop a malignancy is not known. Currently, tumors represent about 2% of the AIDS-defining events in children in the United States, but the incidence might be different in developing countries. The most common tumors in HIV-infected children are non-Hodgkin's lymphoma, smooth muscle tumors (leiomyosarcomas), and Kaposi's sarcoma (only in Africa). This article provides an overview of epidemiology and clinical and pathological presentations, as well as preliminary data regarding treatment options in children with HIV-associated malignancies.  (+info)

(3/107) Myofibroblastoma of the neck in a heifer.

A 1.5-year-old Holstein heifer had a subcutaneous tumor mass (20 cm diameter) on the ventral portion of the neck, and the tumor was diagnosed as a locally invasive myofibroblastoma. It consisted of moderately cellular fibrous tissue, and the interlobular septum of the thymus was invaded by tumor cells. The neoplastic cells were positive for alpha smooth muscle actin and vimentin, but not for desmin. Electron microscopy disclosed the presence of moderately developed rough endoplasmic reticulum and microfilaments with focal densities.  (+info)

(4/107) Recognition of common childhood malignancies.

Although cancer has an annual incidence of only about 150 new cases per 1 million U.S. children, it is the second leading cause of childhood deaths. Early detection and prompt therapy have the potential to reduce mortality. Leukemias, lymphomas and central nervous system tumors account for more than one half of new cancer cases in children. Early in the disease, leukemia may cause nonspecific symptoms similar to those of a viral infection. Leukemia should be suspected if persistent vague symptoms are accompanied by evidence of abnormal bleeding, bone pain, lymphadenopathy or hepatosplenomegaly. The presenting symptoms of a brain tumor may include elevated intracranial pressure, nerve abnormalities and seizures. A spinal tumor often presents with signs and symptoms of spinal cord compression. In children, lymphoma may present as one or more painless masses, often in the neck, accompanied by signs and symptoms resulting from local compression, as well as signs and symptoms of systemic disturbances, such as fever and weight loss. A neuroblastoma may arise from sympathetic nervous tissue anywhere in the body, but this tumor most often develops in the abdomen. The presentation depends on the local effects of the solid tumor and any metastases. An abdominal mass in a child may also be due to Wilms' tumor. This neoplasm may present with renal signs and symptoms, such as hypertension, hematuria and abdominal pain. A tumor of the musculoskeletal system is often first detected when trauma appears to cause pain and dysfunction out of proportion to the injury. Primary care physicians should be alert for possible presenting signs and symptoms of childhood malignancy, particularly in patients with Down syndrome or other congenital and familial conditions associated with an increased risk of cancer.  (+info)

(5/107) Is anti-h-caldesmon useful for distinguishing smooth muscle and myofibroblastic tumors? An immunohistochemical study.

Misinterpretation of positive staining of antibodies to desmin, smooth muscle actin, and muscle actin as representing smooth muscle differentiation in the context of a spindle cell tumor is not uncommon. Anti-h-caldesmon is a promising novel immunohistochemical reagent for more specific smooth muscle differentiation. We studied 72 tumors (11 leiomyosarcomas, 26 malignant fibrous histiocytomas [MFHs], 11 fibromatoses, 11 cellular cutaneous fibrous histiocytomas [CCFHs], 5 malignant peripheral nerve sheath tumors, 4 synovial sarcomas, and 4 cases of nodular fasciitis), the reactive myofibroblastic response in 5 cases of acute cholecystitis, and the desmoplastic response surrounding 5 invasive breast carcinomas. Tissues were examined for expression of h-caldesmon, desmin, smooth muscle actin, and muscle actin. Diffuse staining for h-caldesmon was present only within the leiomyosarcomas. Focal staining for h-caldesmon involving less than 1% of lesional cells was present in 3 of 26 MFHs and 1 of 11 CCFHs. There was overlap in staining for the other "myoid" markers in all of the lesions that contained myofibroblasts. Anti-h-caldesmon seems to be a reliable marker of smooth muscle differentiation, and its inclusion in a panel of myoid immunohistochemical reagents should allow distinction of smooth muscle and myofibroblastic tumors.  (+info)

(6/107) Inflammatory myofibroblastic tumor involving the pterygopalatine fossa.

SUMMARY: Inflammatory myofibroblastic tumors (IMT) comprise a rare group of lesions characterized histologically by acute and chronic inflammatory cells with a variable degree of fibrous stroma. Occurrence in the extracranial head and neck in children is unusual, and involvement in the pterygopalatine fossa has not, to our knowledge, been reported as occurring in this age group. We present the CT findings of an IMT of the pterygopalatine fossa in a 6-year-old female patient with a 2-week history of fever and a painless swelling of the left cheek. The diagnosis of IMT should be included in the differential diagnosis of a child presenting with an aggressive mass associated with systemic features such as fever, elevated sedimentation rate, and leukocytosis.  (+info)

(7/107) Down-regulation of caveolin-1, a candidate tumor suppressor gene, in sarcomas.

Caveolae are plasma membrane microdomains that have been implicated in the regulation of several intracellular signaling pathways. Previous studies suggest that caveolin-1, the main structural protein of caveolae, could function as a tumor suppressor. Caveolin-1 is highly expressed in terminally differentiated mesenchymal cells including adipocytes, endothelial cells, and smooth muscle cells. To study whether caveolin-1 is a possible tumor suppressor in human mesenchymal tumors, we have analyzed the expression using immunohistochemistry in normal mesenchymal tissues, 22 benign and 79 malignant mesenchymal tumors. Caveolin-1 was found to be expressed in fibromatoses, leiomyomas, hemangiomas, and lipomas at high levels comparable to normal mesenchymal tissues. The expression of caveolin-1 was slightly reduced in four of six well-differentiated liposarcomas and strongly reduced or lost in three of three fibrosarcomas, 17 of 20 leiomyosarcomas, 16 of 16 myxoid/round cell/pleomorphic liposarcomas, five of eight angiosarcomas, 15 of 18 malignant fibrous histiocytomas, and eight of eight synovial sarcomas. The immunohistochemical findings were confirmed by Western blot analysis in a number of tumors. High levels of both the 24-kd [alpha]- and the 21-kd [beta]-isoform of caveolin-1 were detected in the nontumorigenic human fibroblast cell line IMR-90. In contrast, in HT-1080 human fibrosarcoma cells, caveolin-1 is strongly down-regulated. We show that the [alpha]-isoform of caveolin-1 is potently up-regulated in HT-1080 cells by inhibition of the mitogen-activated protein kinase-signaling pathway with the specific inhibitor PD 98059, whereas the specific inhibitor of DNA methylation 5-aza-2'-deoxycytidine only marginally up-regulates caveolin-1. In addition, re-expression of caveolin-1 in HT-1080 fibrosarcoma cells potently inhibited colony formation. From these we conclude that caveolin-1 is likely to act as a tumor suppressor gene in human sarcomas.  (+info)

(8/107) Predominant fatty variant of myofibroblastoma of breast.

Myofibroblastoma of the breast is an uncommon but well defined benign stromal tumour. This report describes a case in which the predominant histological component was mature adipose tissue and two further cases with a major adipocytic component. Although small foci of adipose tissue are a recognised feature of this tumour, the dominance of the histological pattern by fat has not been described previously, and the recognition of this variant is important to allow confident diagnosis and avoid confusion with other primary adipocytic or stromal lesions, especially in the setting of potential needle core biopsy of such a lesion.  (+info)