DIAGNOSTIC PITFALL IN THE DIAGNOSIS OF A HISTIOCYTIC SARCOMAARISING IN GASTRO-INTESTINAL TRACT

Histiocytic sarcoma is a rare malignant tumor characterized by histiocytic morphologic and immunophenotypic features. It typically presents extranodally and has a poor clinical outcome, particularly in disseminated cases. Some patients have a history of hematolymphoid disorders, suggesting transdifferentiation from a preexisting hematolymphoid neoplasm. Diagnosis is challenging due to its rarity and histological overlap with various other neoplasms. Judicious use of immunohistochemical markers is essential to confirm its histiocytic lineage and exclude differential diagnoses. Recent molecular studies have identified recurrent alterations in the MAP kinase pathway and chromatin regulators, offering potential new therapeutic targets.