CASE REPORT I
The patient is a 1-year and 9-month-old female child who presented with pancytopenia and a history of atopic and seborrheic dermatitis, repeated febrile otitis, impetigo on the scalp, extensive skin lesions on the perineum, and difficulty walking for 3 months. Initially suspected of leukemia due to pancytopenia, further examination revealed pale skin, lichenized skin lesions on the neck, erythematous and moist skin lesions on various body parts, including the perineum, as well as hepatosplenomegaly and suppurative otitis.
CT scans showed numerous osteolytic lesions affecting multiple bones, including the skullcap, skull base, maxilla, mandible, scapulae, ribs, vertebrae, pelvis, and proximal femurs, in addition to hepatosplenomegaly. Skin biopsy, bone marrow biopsy, and cerebrospinal fluid collection confirmed the diagnosis of Multisystem Histiocytosis (MS-LCH) with involvement of risk organs (liver, spleen, and bone marrow) and bone structures.
The patient initially received vinblastine and prednisolone but exhibited refractory disease. Second-line therapy with Cladribine and Cytarabine also did not eliminate bone marrow infiltration. After a BRAF V600E mutation test confirmed the mutation, treatment with Vemurafenib was initiated, leading to significant improvements in bone marrow infiltration and skin lesions. The patient currently takes Vemurafenib without significant side effects, maintaining an excellent quality of life at 4 years and 11 months of age.