Chediak-Higashi syndrome is a rare autosomal recessive disorder due to a qualitative defect in leucocyte function characterized clinically by partial oculocutaneous albinism, recurrent bacterial infections, photophobia etc. The diagnostic feature is the presence of abnormal giant intracytoplasmic granules in neutrophils and their precursors. Here we report this syndrome in two siblings who presented with an unusual hyperpigmentation of the face and extremities.Key Words: Chediak-Higashi syndrome, Albinism ÖZChediak-Higashi sendromu, otozomal resesif geçiş gösteren, kısmi okülokutanöz albinism, tekrarlayan bakteriyel enfeksiyonlar, fotofobi vb klinik bulgularla karakterize, lökosit fonksiyonunda niteliksel kusura bağlı nadir bir hastalıktır. Nötrofiller ve öncü hücrelerinde dev intrasitoplazmik granüller tanısal bulgusudur. Burada, sıradışı olarak yüz ve ekstremitelerinde hiperpigmentasyon ile kendini gösteren iki kardeşte gözlenen Chediak-Higashi sendromu sunulmaktadır.

“Lineage switch” is term described when leukemic cells on relapse exhibit a new phenotype, where losses of one lineage defining markers with simultaneous gain of another lineage defining markers occur. Relapse of acute leukemia is although a very common event, lineage switch occurs and reported very rarely in such cases. The pathogenesis involved in this phenomenon remains unclear; however plasticity of hematopoietic progenitor affected by intrinsic and extrinsic environmental cues can be a possible explanation. In most of the cases at the time of relapse conversion of B-acute lymphoblastic leukemia (ALL) to acute myeloid leukemia (AML) occurs. Here, we presented an unusual case of 10 year old boy with AML switched to T-ALL upon relapse, which is very rare and not well documented till date in literature. The diagnosis was further supported by morphologic, cytochemistry and flowcytometric immunophenotyping (FCM-IPT). Prognosis and survival of such cases remains poor even by the use of standard chemotherapy.

Non-immunoglobulin intracytoplasmic inclusions in plasma cells of multiple myeloma are very rare presentation. These are morphologically similar to Auer rods but chemically different from them. We studied two cases of multiple myeloma in a 60-year-old woman and 45-year-old man. In both cases, plasma cells of bone marrow aspirate revealed multiple Auer rod-like inclusions (ARLI). Sudan black B (SBB) and myeloperoxidase (MPO) cytochemistry were negative. Serum protein electrophoresis in both of them showed M spike, one with raised IgA-kappa levels, while the other with raised IgG-kappa levels. Very few case reports have been published in the literature and its prognostic implications are still unknown. Due to its rarity, it is important to distinguish such cases from acute myeloid leukemia and its exact incidence with its therapeutic and prognostic implications.

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B-lineage acute lymphoblastic leukemia (B-ALL) is an aggressive neoplasm of B-lymphocyte precursors that express the pan B-cell marker CD19 in all the cases. Rarely, a case may be assigned as B-lineage even if CD19 is negative. Here, a 16-year-old male presented with complaints of pain abdomen, on and off fever, joint pain, and hepatosplenomegaly for 2 months. Bone marrow examination was suggestive of acute leukemia with numerous leukoblasts on aspiration. On flow cytometry, gated blast population was negative for CD19, cytoCD3, and myeloperoxidase MPO and positive for CD34, TdT, HLA-DR, CD22, CD79a, and CD10. Immunohistochemistry study showed positivity for TdT, CD34, CD10 (focal), and PAX 5 and negativity for CD20, CD3, MPO, CD117, and CD68. Lack of awareness of negative CD19 expression in B-ALL can lead to incorrect immunophenotypic diagnosis, treatment, and monitoring of B-ALL. Proper diagnosis should be based on clinical features, immunophenotypic profiles, immunohistochemistry findings, and molecular analysis.