Pleomorphic Hyalinizing Angiectatic Tumor: Immunohistochemical Study with Review of Literature.

Pleomorphic hyalinizing angiectatic tumor (PHAT) is relatively a new entity that was described first in 1996. Although it is often confused with neurilemmoma and low grade malignant fibrous histiocytoma, it is considered to be a distinctive neoplasm because of certain unique microscopic and immunohistochemical findings. It is a low grade, slowly growing tumor that recurs after surgical removal in about a third of all cases. It is not known to metastasize. In this review, we have immunohistochemically analyzed a case of gluteal soft tissue tumor in a 22-year-old woman using CD 34, CD 68, CD 99, S100 and desmin. Classical histological features and positivity for only CD 34 helped in establishing the diagnosis as PHAT. We have reviewed the available literature.

Significance of AgNOR score in benign and malignant soft tissue tumours.

AgNOR staining was employed on FNAC and histopathological sections obtained from patients with soft tissue tumours. The study comprised of 20 normal appearing soft tissues, 74 benign and 36 malignant soft tissue tumours. The slides were stained with AgNOR in order to differentiate between benign and malignant soft tissue tumours. The mean AgNOR count in normal appearing soft tissues, benign lesions and malignant lesions was 1.04+/-0.10 (0.94-1.14), 1.51+/-0.21 (1.1-2.1) and 4.96+/-1.33 (2.57-7.21) respectively. The mean AgNOR count was found to be higher in benign soft tissue tumours as compared to normal appearing soft tissues and the difference was found to be statistically significant. The mean AgNOR count in soft tissue sarcomas was found to be higher as compared to both normal appearing soft tissues and benign soft tissue tumours and the results were found to be statistically significant. The increased AgNOR score in both benign and malignant soft tissue tumours as compared to normal appearing soft tissues indicates high proliferative activity. Thus AgNOR staining is a simple and useful method for estimating tumour cell proliferation thereby differentiating normal appearing soft tissues from benign and malignant soft tissue tumours.

Collagenous fibroma ( desmoplastic fibroblastoma ) of alveolar bone: a case report

O fibroma colagenoso (fibroma desmoplásico) é um tumor de tecido mole raro de origem fibroblástica. Na mucosa oral apenas dois casos foram descritos pela literatura. Nós descrevemos o caso de uma mulher de 42 anos de idade, cuja queixa era uma lesão indolor, de crescimento lento sob sua prótese total superior. Os achados histológicos da lesão incluíram fibroblastos escassos, estrelados ou fusiformes, dispersos em um estroma rico em colágeno. As células lesionais foram positivas para vimentina, mas rara marcação foi observada para actina músculo liso e fator XIIIa. A excisão cirúrgica total foi realizada e a recidiva da lesão não é esperada.

Canine biphasic synovial sarcoma: case report and immunohistochemical characterization

The clinical, radiological and pathologic features of a biphasic synovial sarcoma in the left elbow joint of a two-year-old male Rottweiler are presented. The tumor showed positive immunoreactivity for vimentin, Epithelial Membrane Antigen (EMA), p53 and PCNA, while it was negative for the cytokeratin used, S-100, Rb and p21. Immunohistochemistry for EMA allowed the identification of epithelioid components of synovial sarcoma, and may, therefore, contribute in establishing a diagnosis of biphasic synovial sarcoma. Intratumoral variation in PCNA immunoreactivity was minimal, indicating that the various tumor components proliferate at more or less similar rates. Overall, the characterized immunohistochemical profile for canine synovial sarcoma, not defined previously, may provide clues to the histogenesis of the phenotypically mesenchymal and epithelial elements of the tumor, and may be of value in the differential diagnosis of challenging cases, decreasing the risk of under- and mis-diagnosis. Although more cases need to be studied to determine whether there is a consistent pattern of immunostaining in canine synovial sarcoma, its potential significance is discussed in relation to the histogenesis, molecular pathology and differential diagnosis of canine synovial sarcoma.

Plexiform malignant peripheral nerve sheath tumor(MPNST) in infancy and childhood: a case report

We present a congenital plexiform cellular tumor with high mitotic activities arising in the right thigh of a 3-days-old infant. This subcutaneous tumor measured 6.5 x 4.5 cm in diameter with multinodular, whitish, elastic cut surface. Microscopically, the tumor was composed of fascicles of closely packed uniform spindle cells with frequent nuclear palisadings. The most remarkable finding was frequent mitoses(4-5/10 HPF). The tumor cells were strongly positive for S-100 protein, myelin basic protein and vimentin, and weakly positive for Leu 7. On electron microscopic examination, the spindle cells were found to be surrounded by continuous basal lamina and had interlocking long cytoplasmic processes. Although the prognosis of this tumor is difficult to predict, aggressive behavior such as recurrences may be suggested, but it is less likely to be metastatic. Further accumulation of similar unusual cases may be helpful in evaluation of its biologic behavior.