A rare case of adolescent Histiocytic Sarcoma

Histiocytic sarcoma is a rare haematopoietic malignancy with an aggressive nature and poor prognosis. It occurs infrequently in children and adolescents, with only a few cases reported worldwide. A well 14-year-old male patient presented with a slow-growing mass on his right lateral malleolus. Imaging suggested a benign tumour and an excision biopsy was performed. Morphological examination raised suspicion for a histiocytic neoplasm, which was confirmed by immunohistochemistry (CD68 and CD45 positive, CD1a, CD30 and ALK1 negative). Because of the tumour’s rarity, it was sent for an international confirmatory pathological review. Contribution: Our patient underwent a wide local resection followed by radiotherapy (50 Gy). No adjuvant chemotherapy was prescribed, and he has remained in remission 2 years following his diagnosis.