Rare mediastinal small round cell melanoma with synovial sarcoma-like immunophenotype: A potential diagnostic pitfall.

Melanoma can pose a significant diagnostic challenge due to the high variability in histological morphology and expression of non-melanocytic immunomarkers. We present a case of a 47-year-old male with an aggressive mediastinal neoplasm and disseminated disease posing several diagnostic challenges. Multiple biopsies were submitted from different anatomic locations and during multiple time points showing an undifferentiated round cell tumor (URCT) with synovial sarcoma-like immunophenotype.

Resistance to apoptosis in complicated Crohn's disease: Relevance in ileal fibrosis.

Background And Aims: The stiffening of the extracellular matrix, and changes in its cellular and molecular composition, have been reported in the pathogenesis of fibrosis. We analyze the mechanisms that perpetuate ileal fibrosis in surgical resections of complicated Crohn's disease patients.

Methods: Ileal resections were obtained from affected and non-affected tissue of stenotic or penetrating Crohn's disease behavior.