A 5-year-old female from nonconsanguineous marriage, with a medical history of snoring without sleep apnea, had presented asthenia, gingival bleeding, and diffuse bone pain evolving for three months, without associated fever. Before admission to our hospital, the patient had visited a general practitioner who ordered blood tests. Initial cell blood count showed bicytopenia (microcytic hypochromic anemia at 10.1 g/dL and thrombocytopenia at 100 G/L) with low reticulocytes at 70250/mm3. The patient was referred to the hospital for further investigations. Physical examination showed pallor, gingival hypertrophy, and petechiae over the abdomen. Palpation revealed painless and bilateral cervical lymphadenopathy, without splenomegaly or hepatomegaly. The skeletal examination showed several bony nodules on the forehead, mandible, wrists, and knees.
Cell blood count revealed microcytic hypochromic anemia (hemoglobin = 10.4 g/dL; MCV = 77.4 fL; MCHC = 26.1 pg), thrombocytopenia (platelet count = 84 G/L), and normal white blood cell count at 4.56 G/L (neutrophils = 3.11 G/L; lymphocytes = 1.2 G/L). The erythrocyte sedimentation rate was elevated at 57 mm/hour. Biochemical parameters objectified hyperferritinemia at 241 ng/mL and a high level of lactate dehydrogenase at 688 U/L.
Peripheral blood smear showed anisopoikilocytosis with mild hypochromia, without platelet clumping. Bone marrow aspiration was normocellular with the absence of megakaryocytes. It was infiltrated by 31% of large histiocytes with hypochromatic nuclei and abundant vacuolated cytoplasm, without emperipolesis (Figure 1). An infiltration by mature histiocytic cells was also observed in bone marrow, lymph nodes, and bone biopsies (Figure 2). Immunohistochemically, the histiocytes were positive for CD68 and S100 protein but negative for CD1a (Figure 3). A diagnosis of RDD involving bone marrow and bones was made. No concurrent malignancy was detected. Lymph node tuberculosis was ruled out because there was no histological evidence. Antinuclear antibodies, anti-DNA antibodies, and rheumatoid factor were absent, which ruled out an associated autoimmune disease. Serological tests for hepatitis B and C, syphilis, and cytomegalovirus were negative.
Neck ultrasound confirmed the presence of bilateral cervical lymphadenopathies. Chest and neck CT scan revealed bilateral lytic bone lesion involving both scapulas and bilateral cervical lymphadenopathies.
The patient has first received analgesics as a symptomatic treatment. On day 6 of admission, the patient's clinical course was deteriorated. She presented signs of septic shock: fever at 40 , hypotension with increased C reactive protein at 47 mg/L. The patient was transferred to the pediatric intensive care unit for appropriate management. Empirical antibiotic therapy was initiated (imipenem + vancomycin). However, the blood culture was negative without any microbiological evidence. The patient died one week after admission to the hospital before the final establishment of RDD diagnosis.