Mixed-phenotypic acute leukemia: cytochemically myeloid and phenotypically early T-cell precursor acute lymphoblastic leukemia

Auer rod-positive acute leukemia with predominantly lymphoid immunophenotype: Report on 11 cases and review of literature

BACKGROUND

Auer rods (AuRs) are prominent intracellular structures found almost exclusively in myeloid cell malignancies, such as acute myeloid leukemia (AML), chronic and juvenile myelomonocytic leukemia and myelodysplastic syndrome. Extremely rare AuRs have been reported in patients with acute lymphoblastic leukemia (ALL) or among ambiguous lineage leukemia patients with a dominantly lymphoblastic immunophenotype.

PROCEDURE

We report diagnostic and follow-up data of an international cohort of 11 children suffering from leukemias with AuRs and with significant presence of T and myeloid markers, majority of whom categorized as early T-cell precursor (ETP, n = 7); or T-ALL (ETP status unknown, n = 2), ALAL (acute leukemia of ambiguous lineage, n = 1), and AML reclassified from ALAL (n = 1). We described other diagnostic details and treatment types and responses. Moreover, we summarize previously published data.

RESULTS

Among the four patients who started and remained on ALL-type therapy, all were in the first complete remission, whereas both patients who started and remained on AML-type therapy relapsed and died. Of the patients who followed either a combined ALL/AML protocol (Interfant 06) or who switched from one of the two types of therapy to the other, one patient died, and the remaining four were in first complete remission at the most recent follow-up. We also searched for similar cases in the literature and found only three additional children with nonmyeloid leukemia and AuRs and 10 adults with this type of leukemia.

CONCLUSIONS

Briefly, ALL- or combined ALL/AML-type therapy may be effective for treating AuR-positive leukemia patients with a lymphoid immunophenotype.

Diagnostic challenges in T-lymphoblastic lymphoma, early T-cell precursor acute lymphoblastic leukemia or mixed phenotype acute leukemia: A case report

RATIONALE

The diagnosis of hematological malignancies depends on laboratory analysis and often requires multiple experimental methods to judge, otherwise misdiagnosis is apt to happen. Lymph node biopsy immunohistochemistry (IHC) for T-lymphoblastic lymphoma (T-LBL) requires the establishment of antibody set screening. For identifying T-LBL and early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) by lymph node biopsy and IHC, WHO has not yet proposed a better IHC antibody combination.

PATIENT CONCERNS

Here we reported 1 case with tortuous diagnosis experience. Initially, a 51-year-old man was diagnosed as T-LBL by lymph node biopsy, but in another hospital acute myeloid leukemia (AML) was confirmed by bone marrow puncture. Finally, it was diagnosed as mixed phenotype acute leukemia (MPAL) through our comprehensive evaluation including bone marrow cell morphology, cytochemical staining and flow cytometry analysis. Importantly, the experience about differential diagnosis and our appreciation among the T-LBL, ETP-ALL and MPAL was discussed to enlighten readers.

DIAGNOSES

The patient was diagnosed with mixed phenotype acute leukemia (T+My)-NOS.

INTERVENTIONS

The patient received 1 cycle of VDCLP scheme treatment firstly. The effect of chemotherapy is satisfactory, and then he received continuous treatment and was currently in good condition.

OUTCOMES

This patient is alive at present. The follow-up period has been 1 year.

LESSONS

For the diagnosis of T-LBL, the molecular markers of the myeloid and lymphoid tissues need to be included, such as CD117, CD33, Lys and MPO. The bone marrow puncture also needs to be conducted to distinguish T-LBL and T-ALL. Secondly, to identify ETP-ALL and MPAL, bone marrow cell morphology, cytochemical staining as well as flow cytometric analysis were needed to make a clear diagnosis. It is recommended that at least CD8, CD1a, Lys and MPO should be included in the panel to identify ETP-ALL.

[The specific features of diagnosis of mixed-phenotype acute leukemia: A combination of B-cell antigen expressions according to the results of flow cytometry and morphological markers of myeloid differentiation in blast cells: A clinical case]

This rare type of acute leukemia, blast cells of which express myeloid and/or lymphoid markers, is mainly diagnosed using flow cytometric findings. The paper describes a clinical case of mixed-phenotype acute leukemia, in which B-cell lymphoid antigen expressions were revealed by a flow cytometric technique, while bone marrow morphological specimens showed the signs of myeloid differentiation specific to blast cells. It is concluded that there is a need for a comprehensive examination of patients with new-onset acute leukemia and for an aggregate analysis of flow cytometric results with morphological and cytochemical findings.