Frequency and Prognostic Relevance of FLT3 Mutations in Saudi Acute Myeloid Leukemia Patients.

The Fms-like tyrosine kinase-3 (FLT3) is a receptor tyrosine kinase that plays a key role in cell survival, proliferation, and differentiation of hematopoietic stem cells. Mutations of FLT3 were first described in 1997 and account for the most frequent molecular mutations in acute myeloid leukemia (AML). AML patients with FLT3 internal tandem duplication (ITD) mutations have poor cure rates the prognostic significance of point mutations; tyrosine kinase domain (TKD) is still unclear. We analyzed the frequency of FLT3 mutations (ITD and D835) in patients with AML at diagnosis; no sufficient data currently exist regarding FLT3 mutations in Saudi AML patients. This study was aimed at evaluating the frequency of FLT3 mutations in patients with AML and its significance for prognosis. The frequency of FLT3 mutations in our study (18.56%) was lower than many of the reported studies, FLT3-ITD mutations were observed in 14.4%, and FLT3-TKD in 4.1%, of 97 newly diagnosed AML patients (82 adult and 15 pediatric). Our data show significant increase of FLT3 mutations in male more than female (13 male, 5 female). Our results support the view that FLT3-ITD mutation has strong prognostic factor in AML patients and is associated with high rate of relapse, and high leucocytes and blast count at diagnosis and relapse.

Generalized lymphadenopathy as the first presentation of granulocytic sarcoma: a diagnostic challenge.

Introduction. Granulocytic sarcoma (GS), also known as chloroma or extramedullary myeloblastoma, is a solid tumor composed of primitive precursors of the granulocytic series that include myeloblasts, promyelocytes, and myelocytes. Granulocytic sarcoma is a rare tumor that may develop during acute myeloid leukemia (AML) but less frequently may precede its presentation. Although generalized lymph node enlargement is a presentation for malignant lymphoma, it can also rarely be the early presenting sign of GS. Methods. We present a case of GS mimicking lymphoma in a 45-year-old male. The patient presented with bilateral neck masses and had widespread, prominent lymphadenopathy secondary to AML as the first presenting manifestation of GS for the last 4 months with concurrent marrow AML. Result. A clinical diagnosis of lymphoma was suspected; fine needle aspiration cytology findings were also suggestive of lymphoma. However, peripheral blood and bone marrow examination reported as acute myeloid leukemia with monocytic differentiation and histopathology of excised lymph node confirmed it to be a GS not lymphoma. Conclusion. GS is often misdiagnosed as malignant lymphoma because of cytomorphologic and histologic similarities of the blasts to large cell lymphoma. A careful search for immature myeloid is a useful clue to the diagnosis accompanied with appropriate immunophenotyping.