Misdiagnosed Histiocytic Sarcoma: A Case Report.

We report a 31-year-old male patient repeatedly hospitalized for mimicking infectious symptoms. Following standardized anti-infective and anti-inflammatory treatment, clinical evolution was discordant, characterized by treatment non-response and symptom exacerbation. Ultimately, the multidisciplinary team and repeated histopathological examinations diagnosed histiocytic sarcoma (HS). Unfortunately, the treatment opportunity was lost due to HS's high aggressiveness and rapid progression.