Submitting Author: Ayyad, Hashem, MD
Institution: Henry Ford Hospital
Additional authors:Kistin Hunt Karner MD, Kedar Inamdar MD, PhD
Session: Acute leukemias of ambiguous lineage

This is an 82 year old male patient with a past medical history including hypertension, hyperlipidemia, remote myocardial infarction with normal ejection fraction, abdominal aortic aneurysm, and arthritis. The patient also has family history of acute leukemia in a sibling. The patient was being followed in the hematology clinic for thrombocytopenia and macrocytic anemia for the last ten years. The patient presented with fatigue and dizziness and his CBC showed anemia (hemoglobin 8.3 g/dL), thrombocytopenia (platelet count 1300 /uL) and neutropenia (absolute neutrophil count 230 /uL). A bone marrow was done and revealed extensive involvement by acute leukemia. The decision was made not to administer chemotherapy due to multiple comorbidities and the patient was referred to hospice care. No information regarding the patient's duration of survival is available

The marrow is hypercellular for age (55% cellularity) and is extensively involved by leukemic blasts, constituting 66% of all nucleated cells. The blasts are intermediate in size with very high nucleus to cytoplasm ratio, fine chromatin with nucleoli ranging in appearance from inconspicuous to occasionally large and prominent. The scant cytoplasm is grey and contains occasional fine pink granules and occasional vacuoles. The blasts are negative for sudan black B and non specific esterase cytochemical stains. Megakaryocytes and erythroid lineage are markedly decreased but without dysplastic features

By flow cytometry:

Positive markers: T-lineage: cytoplasmic CD3, CD7

. B-lineage: CD19, CD22 (heterogeneous). Myeloid: CD13, CD117, and CD15 (minority)

The blast cells are negative for CD5, CD11b, CD14, CD33, CD56, CD61, CD79a, CD235a, and myeloperoxidase (MPO).

Conventional cytogenetics: Normal male karyotype.

FISH: Fluorescent in situ hybridization (FISH) for MDS was performed with probes 5p15.2 (D5S23), 5q31 (EGR1), 7cen (D7Z1), 7q31 (D7S486), 8cen (D8Z2), 11q23(MLL), 13q14 (D13S319), 13q34 (LAMP1) and 20q12 (D20S108). All results were negative

The diagnosis of this case rests on how the intensity of the B-cell markers on flow cytometry are interpreted, as neither CD19 nor CD22 are exhibiting bright intensity. The myeloid markers are interpreted as aberrant and are not truly indicative of myeloid differentiation according to EGIL / WHO 2008 classification schemes.

Acute lymphoblastic leukemia, biphenotypic (B/T)

Mixed phenotype acute leukemia (B/T)

Case 390