Familial hemophagocytic lymphohistiocytosis in a 6-week-old male infant.

Familial hemophagocytic lymphohistiocytosis (FLH) is an autosomal recessively inherited multisystem disease. This defect in cellular cytotoxicity is a life threatening condition characterized by fever, rash, splenomegaly, cytopenias and neurologic manifestations. PRF1, UNC13D and STX11 gene defects underlie in about 40-50% of primary cases. Chemoimmunotherapy followed by hematopoietic stem cell transplantation improved disease outcome. We report a case of a 6-week-old boy who presented with a fever, diffuse rash, disseminated intravascular coagulation, hypofibrinogenemia, hypertrigliceridemia, hepatosplenomegaly, leukocytosis with 90% of lymphocytes, granulocytopenia, anemia, trombocytopenia, hyperferritinemia and pathological findings in cerebrospinal fluid. The patient had decreased frequency of NK cells and low NK cell activity in peripheral blood. Bone marrow aspiration analysis showed degenerative changes of histocyte cells, with preserved cytophages (lymphophages and erythrophages) consistent with hematophagocytic syndrome. Given that the molecular diagnosis of the known mutations in genes PRF1 and UNC13D showed a mutation in UNC13D, the diagnosis of familial hemophagocytic lymphohistiocytosis subtype 3 was established. HLH-2004 chemotherapy protocol was performed and partial remission with residual central nervous system disease was achieved. Hematopoietic stem cell transplantation was successfully performed with an unrelated HLA-matched donor. Familiar HLH is generally a progressive and fatal disease. Early diagnosis with molecular genetic analysis and chemoimmunotherapy followed by hematopoietic stem-cell transplantation is the best approach.

Juvenile myelomonocytic leukemia with PTPN11 mutation in a 23-month-old girl.

Juvenile myelomonocytic leukemia (JMML) is a rare clonal myeloproliferative disorder affecting young children. The natural course of JMML is rapidly fatal with 80% of patients surviving less than three years. Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative treatment of JMML. We report a case of a 23-month-old girl who presented with an upper respiratory tract infection, fever, rash, diarrhea, hepatosplenomegaly and abdominal distention. Severe elevation of white blood cell count with monocytosis and myeloid progenitors in the peripheral blood was also detected. Bone marrow smear showed morphology suggestive of JMML, an unspecific immune phenotype and a normal karyotype. DNA analysis revealed a mutation in the PTPN11 gene. Therefore, the final diagnosis of JMML with somatic PTPN11 mutation was established. Following three months of cytostatic therapy with 6-mercaptopurine and low doses of cytarabine partial remission was achieved and allogeneic HSCT was successfully performed. Six months after the diagnosis, the girl was in a good condition and in a complete remission of JMML. Early diagnosis and allogeneic HSCT were crucial for successful treatment outcome.

Pre-B-cell acute lymphoblastic leukemia with bulk extramedullary disease and chromosome 22 (EWSR1) rearrangement masquerading as Ewing sarcoma.

We report a 2-year-old female with a subcutaneous tumor who was initially misdiagnosed as suffering from Ewing sarcoma with a positive EWSR1 rearrangement and EWS/FLI1 transcript. After finding lymphoblasts in peripheral blood, the diagnosis of acute lymphoblastic leukemia was established. This necessitated further analysis of the subcutaneous tumor. The tissue was positive for immature B-cell markers and an immunoglobulin heavy chain gene rearrangement, which confirmed the final diagnosis of common type acute lymphoblastic leukemia with bulk extramedullary disease. The patient was treated with chemotherapy and was in remission 30 months after the diagnosis.

[Role of the clinician in cytologic diagnosis]. / Uloga klinicara u donosenju citoloske dijagnoze.

In the course of continuing education for physicians on nongynaecological cytology, together with the topics about development and actual situation in clinical cytology, especially in Croatia, as well as those about the technical procedures in cytology, the clinicians' participation in the interpretation of cytological diagnosis was discussed. The term "clinicians" is used here for those physicians who need a rapid, accurate and nonaggressive morphological diagnostic method for the treatment of their patients. The central part of the course was a round-table discussion about the role of clinicians in making cytological diagnosis, with participation of cytologists and clinicians from various branches of medicine, who are either cytologists, or have a good contact with cytologists. They answered questions about the clinicians' information on cytology, about the contact and collaboration between cytologists and clinicians, and about their own experience in everyday cytological practice. The aim of this discussion was to provide sufficient information to clinicians on cytological diagnostics, and the emphasis on team-work was made.