ABSTRACT
We present two cases of solitary fibrous tumour (SFT) showing biphasic morphology with a spectrum of malignant epithelioid components. Slides prepared from formalin-fixed and paraffin-embedded tissue from both cases were stained with haematoxylin and eosin and by immunohistochemistry. Interphase fluorescent in situ hybridisation studies were performed in both cases using paraffin-embedded tissue to look for the t(X;18) translocation, thereby to exclude synovial sarcoma. Both cases showed biphasic morphology with some areas having typical benign spindled SFT morphology (including CD34 expression) and other areas having a malignant epithelioid appearance. In one of the cases, the epithelioid area, which was well circumscribed and showed packeting of cell groups, demonstrated expression of cytokeratin and epithelial cadherin but not of CD34. In the second case, the immunophenotype of the epithelioid component was similar to that of the benign SFT component. These findings suggest that epithelioid change in SFT shows a range of differentiation at one end, similar to that of a standard SFT, and at the other end, possibly acquiring epithelial characteristics.
Subject(s)
Epithelioid Cells/pathology , Soft Tissue Neoplasms/pathology , Solitary Fibrous Tumors/pathology , Biomarkers, Tumor/analysis , Cell Transformation, Neoplastic , DNA, Neoplasm/analysis , Diagnosis, Differential , Epithelioid Cells/chemistry , Female , Humans , In Situ Hybridization, Fluorescence , Male , Middle Aged , Sarcoma, Synovial/diagnosis , Soft Tissue Neoplasms/chemistry , Soft Tissue Neoplasms/surgery , Solitary Fibrous Tumors/chemistry , Solitary Fibrous Tumors/surgeryABSTRACT
The authors report a case of a gastrointestinal stromal tumour (GIST) of the gallbladder. GISTs are rare mesenchymal tumours of the gastrointestinal tract, mesentery and omentum. GISTs are characterized by the expression of the KIT protein, a transmembrane tyrosine kinase receptor for stem-cell factor. Only a few GISTs of the gallbladder have been described in the literature. The behaviour of these tumours is not fully understood but long-term survival is rare. Initial treatment consists of aggressive surgery. Radiotherapy and conventional chemotherapy have been mostly unsuccessful. More recently promising studies have been performed with Imatinib, an orally administered tyrosine kinase inhibitor, in patients with advanced disease.