Acute promyelocytic leukemia

Acute promyelocytic leukemia
Micrograph of acute promyelocytic leukemia, showing characteristic promyelocytes
Synonyms	N/A
Pronounce	N/A
Specialty	N/A
Symptoms	Fatigue, bleeding, bruising, fever, infection
Complications	Disseminated intravascular coagulation, hemorrhage
Onset	Adulthood
Duration	Variable
Types	N/A
Causes	Genetic mutation (translocation between chromosomes 15 and 17)
Risks	Radiation, benzene exposure, chemotherapy
Diagnosis	Bone marrow biopsy, blood test
Differential diagnosis	Acute myeloid leukemia, chronic myeloid leukemia
Prevention	N/A
Treatment	All-trans retinoic acid, arsenic trioxide, chemotherapy
Medication	N/A
Prognosis	Generally good with treatment
Frequency	Rare
Deaths	N/A

Acute Promyelocytic Leukemia (APL) is a subtype of acute myeloid leukemia (AML), characterized by the accumulation of promyelocytes in the bone marrow. It is classified as AML-M3 in the French-American-British (FAB) classification system.

Pathophysiology

APL is caused by a specific chromosomal translocation, t(15;17)(q24;q21), which results in the fusion of the promyelocytic leukemia (PML) gene on chromosome 15 and the retinoic acid receptor alpha (RARA) gene on chromosome 17. This PML-RARA fusion protein interferes with normal hematopoiesis and leads to the accumulation of promyelocytes.

Clinical Presentation

Patients with APL often present with symptoms related to cytopenias and coagulopathy. Common symptoms include:

• Fatigue and weakness due to anemia
• Infections due to neutropenia
• Bleeding and bruising due to thrombocytopenia and disseminated intravascular coagulation (DIC)

Diagnosis

The diagnosis of APL is confirmed through:

• Complete blood count (CBC) showing cytopenias
• Bone marrow biopsy revealing promyelocytes
• Cytogenetic analysis to detect the t(15;17) translocation
• Molecular testing for the PML-RARA fusion gene

Treatment

The treatment of APL has been revolutionized by the introduction of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO). The standard treatment regimen includes:

• Induction therapy with ATRA and ATO
• Consolidation therapy to eliminate residual disease
• Maintenance therapy to prevent relapse

Prognosis

The prognosis for patients with APL has improved significantly with modern treatment protocols. The 5-year survival rate is over 80% with appropriate therapy. Early diagnosis and treatment are crucial to prevent complications such as DIC.

Complications

Complications of APL include:

• Disseminated intravascular coagulation (DIC)
• Differentiation syndrome
• Relapse

Additional images

• 

  Faggot cell in AML-M3

• 

  Peripheral blood smear of acute promyelocytic leukemia, hypogranular variant

• 

  Acute promyelocytic leukemia, hypogranular variant (M3v)

See Also

• Acute myeloid leukemia
• Chromosomal translocation
• Hematopoiesis

External Links

• [American Cancer Society: Acute Promyelocytic Leukemia]
• [Leukemia & Lymphoma Society: APL]