Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0019621 (Langerhans cell histiocytosis)
 3,250 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Infantile myofibromatosis is a mesenchymal disorder of early childhood characterized by the formation of tumors in the skin, muscle, viscera, bone, and subcutaneous tissue. Although relatively rare overall, it represents the most common fibrous tumor of infancy. The etiology of this disorder is unknown. Infantile myofibromatosis can present as a solitary or multicentric form. With the multicentric form, bone is often involved, but solitary bone lesions account for only 10% of the cases. Imaging findings are not pathognomonic, and the differential diagnosis usually includes eosinophilic granuloma (Langerhans cell histiocytosis), osteomyelitis, metastasis, osteoblastoma, epidermoid cyst, hemangioma, fibrous dysplasia, fibrosarcoma, and meningioma. A histological pattern is typical, but there are no histopathological differences between the solitary and multicentric forms. Solitary lesions generally have a favorable prognosis if totally removed, with a 10% recurrence rate; incompletely resected lesions recur. We report the case of a 9-year-old boy who came to our attention with a solitary infantile myofibroma of the calvarium, appearing as a tight-elastic, lightly tender mass in the left frontal area, eroding both the inner and the outer tables. Histopathologically, the specimens showed a spindle-cell tumor with dense reticulin fiber network and expression of smooth muscle actin. Fifty-eight months MR follow-up after total removal showed no residual or relapse.
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PMID:Solitary infantile myofibromatosis of the cranial vault: case report. 2127 63

Alpha isoform of smooth muscle actin (SMA) expression has been reported in giant cell tumour of bone (GCTB) and other benign and malignant bone tumours, but the pattern of SMA expression and the precise nature of SMA-expressing cells in these lesions is uncertain. We determined by immunohistochemistry the expression of SMA and other muscle and vascular markers in normal bone, GCTB and a wide range of primary benign and malignant bone tumours. Cultured stromal cells of GCTB, chondroblastoma (CB), and aneurysmal bone cyst (ABC) were also analysed for SMA expression. SMA was only noted in blood vessels in normal bone. SMA was expressed by mononuclear stromal cells (MSC) cultured from GCTB, ABC and CB. SMA was strongly and diffusely expressed by MSC in non-ossifying fibroma, fibrous dysplasia, and "brown tumour" of hyperparathyroidism. SMA expression was also noted in GCTB, ABC, CB, chondromyxoid fibroma, malignant fibrous histiocytoma of bone and osteosarcoma. Little or no SMA was noted in Langerhans cell histiocytosis, simple bone cyst, Ewing's sarcoma, osteoblastoma, osteoid osteoma, enchondroma, osteochondroma, chondrosarcoma, myeloma, lymphoma, chordoma and adamantinoma. Our findings show that there is differential SMA expression in primary bone tumours and that identifying the presence or absence of SMA is useful in the differential diagnosis of these lesions. The nature of SMA-expressing cells in bone tumours is uncertain but they are negative for desmin and caldesmon and could represent either myofibroblasts or perivascular cells, such as pericytes.
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PMID:Smooth muscle actin expression in primary bone tumours. 2254 53

A 64-year-old male farmer presented with a rapidly progressive swelling of the left mandible since 6 months. The swelling was firm to hard, diffuse, nontender, obliterating the vestibule with paresthesia of lower lip. The cone beam computed tomography imaging revealed an ill-defined, moth-eaten radiolucency with destruction of the buccal and lingual cortical plates. The rapid growth and aggressive behavior of the lesion coupled with guidance from the patient's previous reports from the incisional biopsy and fine needle aspiration cytology warranted a mandibular resection. Microscopic examination showed an encapsulated lesion situated in the connective tissue containing a mixture of proliferating spindle-shaped cells arranged in fascicles and round cells infiltrating into the connective tissue stroma and bone. The neoplastic cells exhibited atypical features such as pleomorphism, hyperchromatism and increased mitotic figures with noncleaved nuclei. A working diagnosis of a spindle-cell sarcoma was arrived at with various differentials provided such as fibrosarcoma, rhabdomyosarcoma, leiomyosarcoma, malignant peripheral nerve sheath tumor, Langerhans cell histiocytosis and lymphoma and stating the need for immunohistochemistry to subtype the tumor. The neoplastic cells were negative for Van Gieson's stain and Masson's trichrome. Immunohistochemical analysis performed using desmin, smooth muscle actin, S-100 and CD1a in a bid to determine the phenotype of the tumor and rule out the previously stated differentials were all negative for the lesion. Lymphoid markers such as leukocyte common antigen and CD20 (cluster differentiation marker for B-cells) showed positivity in spindle-shaped cells as well as round cells indicating the tumor to be a lymphoproliferative lesion of B-cell type. A final diagnosis of "spindle-cell variant of non-Hodgkin's lymphoma" was rendered based on the immunohistochemical profile.
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PMID:A rare spindle-cell variant of non-Hodgkin's lymphoma of the mandible. 2719 75