Mesenchymal Chondrosarcoma: A Rare Aggressive Variant of Chondrosarcoma

A 15-year-old boy reported a 2-month history of severe left thigh pain Physical examination revealed left thigh swelling measuring 6x5 cm. X-ray of the region showed mixed lytic and sclerotic lesion involving the femoral head and neck. A Computed Tomography scan showed mixed lytic and sclerotic lesion involving the femoral head and neck with cortical irregularity and mild periosteal reaction with associated soft tissue in the anterior aspect. Magnetic resonance imaging demonstrated heterogeneous signal intensity lesion with areas of sclerosis involving the femoral head and neck. The large associated soft tissue in the anterior aspect appears predominantly hyperintense on T2W images. On post-contrast axial and sagittal images, heterogeneous enhancement with areas of necrosis involving soft tissue was seen. A presumptive radiological differential diagnosis of Ewing Sarcoma and Osteosarcoma was made. However, on histopathology, it was a case of mesenchymal chondrosarcoma.

Evaluation of the Diagnostic Potential of uPAR as a Biomarker in Renal Biopsies of Patients with FSGS

Minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) are primary glomerulopathies leading to proteinuria, known as podocytopathies, which share syndromic and morphological similarities. Morphological similarity occurs in cases of FSGS in which the sclerotic lesion was not sampled in renal biopsy, due to the focal nature of the disease. Differentiating these entities is very important, especially in cases of suspected FSGS but with sclerotic lesion not sampled, as they are diseases that apparently have different pathogenic mechanisms and prognosis. The difference in uPAR expression in situ among these two entities may be related to a distinct molecular mechanism involved in pathogenesis. Thus, finding biomarkers involved in the pathogenesis and that can also help in differential diagnosis is very relevant. The aim of this work was to evaluate the potential of urokinase-type plasminogen activator receptor (uPAR) as a biomarker in renal biopsies of patients with podocytopathies (n=38). Immunohistochemistry showed that FSGS (n=22) had increased uPAR expression in podocytes compared with both the MCD group (n=16; p=0.0368) and control group (n=21; p=0.0076). ROC curve (p=0.008) showed that this biomarker has 80.95% of specificity in biopsies of patients with FSGS. Therefore, uPAR presented a high specificity in cases of podocytopathies associated with sclerosis and it can be considered a potential biomarker for FSGS.