PATH - Leukemias

Question 1

Leukemias

Answer 1

Unregulated growth and differentiation of WBCs in bone marrow–>marrow failure–>anemia (DEC RBCs), infections (DEC mature WBCs), and hemorrhage (DEC platelets)

Usually presents with
 circulating WBCs (malignant leukocytes in blood)

Leukemic cell infiltration of liver, spleen, lymph nodes, and skin (leukemia cutis) possible.

Question 2

Acute lymphoblastic

leukemia/lymphoma (ALL)

Answer 2

Lymphoid Leukemia

Most frequently occurs in children

*t(12;21)–>better prognosis.

Peripheral blood and bone marrow have INC INC INC lymphoblasts

TdT+, CD10+

T-cell ALL can present as mediastinal mass

Associated with Down syndrome (*bc Chr 21)

Most responsive to therapy.

May spread to CNS and testes.

Question 3

Chronic lymphocytic

leukemia(CLL)/small lymphocytic lymphoma (SLL)

Answer 3

Lymphoid Leukemia

Most common adult leukemia Age: > 60 years.

*CD20+, CD5+ B-cell neoplasm

• smudge cells in peripheral blood smear
• “CLL = Crushed Little Lymphocytes (smudge cells).”

autoimmune hemolytic anemia

*Richter transformation—SLL/CLL transformation into an aggressive lymphoma, most commonly *diffuse large B-cell lymphoma (DLBCL).

Question 4

Hairy cell leukemia

Answer 4

Lymphoid Leukemia

Mature B-cell tumor

*CD27

Adult males

Cells have filamentous, hair-like projections (fuzzy appearing on LM)

Causes marrow fibrosis–>*dry tap on aspiration.

*massive splenomegaly

Stains *TRAP⊕

TX: cladribine, pentostatin

Question 5

Acute myelogenous leukemiaa (AML)

Answer 5

Myeloid Leukemia

*Auer rods
*myeloperoxidase⊕ cytoplasmic inclusions
INC INC INC circulating myeloblasts on peripheral smear
*CD34

Median onset 65 years

Risk factors: prior exposure to alkylating chemotherapy, radiation, myeloproliferative disorders, Down syndrome.

t(15;17)–>APL subtype responds to all-trans retinoic acid (vitamin A), inducing differentiation of promyelocytes

DIC is a common presentation.

TX: all-trans retinioic acid (VIT A)

Question 6

Chronic myelogenous

leukemia

Answer 6

Myeloid Leukemia

peak incidence 45–85 years, median age at diagnosis 64 years

**Philadelphia chromosome (t[9;22], BCR-ABL)

Presents with dysregulated production of mature and maturing granulocytes (eg, neutrophils, metamyelocytes, myelocytes, basophils)

*Very low LAP

splenomegaly

May accelerate and transform to AML or ALL (*“blast crisis”).

TX: imatinib, Responds to bcr-abl tyrosine kinase inhibitors