Neoplastic and Hematologic Pathology

By Paulina Castillo

Primary Brain Tumors

• Clinical presentation due to mass effects

e.g., seizures, dementia, focal lesions• 1° brain tumors rarely undergo metastasis• Majority of adult tumors are supratentorial• Majority of childhood tumors are infratentorial• About ½ of adult brain tumors are metastasis

(Tentorial membrane is a fold of the dura mater that has its free margin surrounding the midbrain and a fixed margin attached to the skull at the top of the posterior fossa. It separates the cerebellum from the cerebral hemispheres)

Adult Brain Tumors

A. Glioblastoma Multiforme (grade IV astrocytoma)

- most common 1° brain tumor

- Grave prognosis < 1-year life expectancy

- found in cerebral hemispheres- can cross corpus callosum butterfly glioma (CC – arched brigde of nervous tissue that connects the two cerebral hemispheres, allowing communication between the right and left sides of the brain)

- “pseudopalisading” tumor cells border central areas of necrosis and hemorrhage

Glioblastoma Multiforme

B. Meningioma

• 2nd most common 1° brain tumor

• Most often occurs in convexities of hemispheres and parasagittal region

• Arises from arachnoid cells external to brain

• Resectable

• Spindle cells concentrically arranged in a whorled pattern

• Psammoma bodies (laminated calcifications)

Meningioma

Convexity meningioma attached to the dural leaflet and indenting the underlying brain

Whorled pattern and psammoma body

C. Schwannoma

• 3rd most common 1° brain tumor • Schwann cell origin• Often localized to 8th nerve Acoustic Schwannoma• Bilateral schwannoma found in neurofibromatosis

type 2• Resectable

Schwannoma

D. Oligodendroglioma

• Relatively rare

• Slow growing

• Most often in frontal lobes

• “Fried egg” cells – round nuclei with clear cytoplasm; often calcified

Classic fried-egg appearance with perinuclear halos

Oligodendroglioma

E. Pituitary Adenoma

• Prolactin secreting is most common form

• Sequalae:

- Bitemporal hemianopia (due to pressure on optic chiasm)

- Hyper- or hypopituitarism

• Rathke’s pouch

Pituitary Adenoma

Childhood Brain Tumors

F. Low-grade astrocytoma (pilocytic astrocytoma)

- diffusely infiltrating glioma

- in children, most often found in posterior fossa

- benign

- good prognosis

- Rosenthal fibers

G. Medulloblastoma

• Highly Malignant cerebellar tumor

• A form of primitive neuroectodermal tumor (PNET)

• Can compress 4th ventricle causing hydrocephalus

• Rosettes or perivascular pseudorosette pattern of cells

• radiosensitive

H. Ependymoma

• Ependymal cell tumors

• Most commonly found in 4th ventricle

• Can cause hydrocephalus

• Characteristic perivascular rosettes

• Rod-shaped blepharoplasts (basal ciliary bodies) found near the nucleus

I. Hemangioblastoma

• Most often cerebellar

• Associated with von Hippel-Lindau syndrome when found with retinal angiomas

• Can cause EPO 2° polycythemia

• Foamy cells and high vascularity are characteristic

J. Craniopharyngioma

• Benign childhood tumor

• Confused with pituitary adenoma (can also cause bitemporal hemianopia)

• Most common childhood supratentorial tumor

• Derived from remnants of Rathke’s pouch

• Calcification in common

Pathology - Neoplastic

• Metastasis to brain- 1° tumors that metastasize to brain:Lung Lots ofBreast BadSkin(melanoma) StuffKidney(RCC) KillsGI Glia- Approximately 50% of brain tumors are

from metastases

Pathology – Neoplastic Cont’d

• Metastasis to Liver

- the most common sites of metastasis after

regional lymph nodes are liver and lung

- 1° tumors that metastasize to the liver are:

Colon > Stomach > Pancreas > Breast > Lung

- Cancer Sometimes Penetrates Benign Liver

- Metastasis to the liver >> 1° liver tumors

Pathology – Neoplastic Cont’d

• Metastasis to bone- 1° tumors that metastasize to bone are:

Breast, Lung, Thyroid, Testes, Kidney, ProstateBLT with a Kosher Pickle

- metastases from breast and prostate are most common- metastatic bone tumors are much more common than 1° bone tumors- Lung = Lytic Prostate = blastic- Breast = Both lytic and blastic

Paraneoplastic Effects of Tumors

• Small cell lung carcinoma

- causes: ACTH or ACTH-like peptide

- effect: Cushing’s Syndrome• Small cell lung carcinoma & intracranial neoplasms

- causes: ADH or ANP

- effect: SIADH• Squamos cell carcinoma, RCC, breast carcinoma,

multiple myeloma, & bone metastasis (lysed bone)

- causes: PTH-related peptide, TGF-β, TNF-α, IL-1

- effect: Hypercalcemia

Paraneoplastic Effects Cont’d

• Renal cell carcinoma- causes: erythropoietin- effects: polycythemia

• Thymoma, bronchogenic carcinoma- causes: antibodies against presynaptic Ca2+

channels at neuromuscular junction- effect: Lambert-Eaton Syndrome (muscle weakness)

• Leukemias and Lymphomas- causes: hyperuricemia due to excess nucleic

acid turnover (i.e., cytotoxic therapy)- effects: gout, urate nephropathy

Cancer Epidemiology

Incidence Mortality

Male Female

Lung (33%)

Prostate (13%)

Lung ( 23%)

Breast (18%)

Male Female

Prostate (32%)

Lung (16%)

Colon & Rectum(12%)

Breast (32%)

Lung (13%)

Colon & Rectum(13%)

-Deaths from lung cancer have plateaued in males but continue to increase in females-Cancer is the 2nd leading cause of death in the U.S. (heart disease is 1st)

Pathology - Hematologic

- Anemias:1. Microcytic, hypochromic (MCV<80)

a. Iron Deficiencies - ↓ serum iron, ↑ TIBC, ↓ferritinb. Thalassemias – target cellsc. Lead poisoning, sideroblastic anemias

2. Macrocytic (MCV > 100)

a. megaloblastic – Vit. B12/folate deficiency

- vit. B12 & folate deficiencies are ass. with hypersegmented PMNs

- vit. B12 deficiency is ass. with neurologic problemsb. drugs that block DNA synthesis (e.g., sulfa drugs, AZT)

c. marked reticulocytosis

Pathology – Hematologic cont’d

3. Normocytic, normochromica. acute hemorrhageb. enzyme defects (e.g., G6PD deficiency, PK deficiency)c. RBC membrane defects (e.g., aplastic anemia, leukemia)d. hemoglobinopathies (e.g., sicke cell disease)e. autoimmune hemolytic anemiaf. anemia of chronic disease (ACD) - ↓TIBC, ↑ferritin, ↑storage iron in marrow macrophages

- ↓serum haptoglobin & ↑serum LDH indicate RBC hemolysis- Direct Coomb’s – used to distinguish b/w immune vs. non-

immune mediated RBC hemolysis

Aplastic Anemia

• Pancytopenia characterized by severe anemia, neutropenia, & thrombocytopenia

- caused by failure or destruction of multipotent myeloid stem cells w/ inadequate production or release of differentiated cell lines

• Causes: radiation, benzene, chloramphenical, alkylating agents, antimetabolites, viral agents, Fanconi’s anemia, idiopathic; may also follow acute hepatitis

Aplastic Anemia Cont’d

• Symptoms: fatigue, malaise, pallor, purpura, mucosal bleeding, petechiae, infection

• Pathologic Features: pancytopenia w/ normal cell morphology; hypocellular bone marrow w/ fatty infiltration

• Diagnosis: made w/ bone marrow biopsy• Treatment: withdrawal of offending agent,

allogenic bone marrow transplant, RBC & platelet transfusion, G-CSF or GM-CSF

Hereditary Spherocytosis

• intrinsic, extravascular hemolysis due to spectrin or ankyrin defect

• RBCs are small & round w/ no central pallor ↑MCHC, ↑RDW, ↑reticulocytes

• Osmotic fragility test used to confirm• Ass. w/ gallstones, splenomegaly, anemia, &

jaundice• Distingued from warm antibody hemolysis by

direct Coombs’ test• Coombs’ negative

Blood Dyscrasias

• Sickle Cell Anemia- HbS mutation is a single aa replacement in β chain (Glu Val)- low O2 or dehydration precipitates sickling- heterozygotes (SC trait) are relatively malaria resistant- complications in homozygotes:

- aplastic crisis (due to parvovirus B19)- autosplenectomy- ↑ risk of encapsulated organism infection- salmonella osteomyelitis- painful crisis (vaso-occlusive)- splenic sequestration crisis

Sickle Cell Anemia Cont’d

- HbC defect is a different β-chain mutation

- pts. w/ HbC or HbSC (1 of each mutant gene) have milder disease than HbSS pts.

- New therapies for SCA include hydroxyurea (↑HbF) & bone marrow tranplantation

- 8% of African-Americans carry the HbS trait- 0.2% have the disease- sickle cells are crescent-shaped RBCs- “crew cut” on skull x-ray due to marrow expansion

Blood Dyscrasias Cont’d

• α-thalassemia- normally there are 4 α-globin genes

- in α-thalassemia, the α-globin is underproduced- there is no compensatory increase of any other

chains

- HbH: β4-tetramer, lacks 3 α-globin genes

- Hb Barts: γ4-tetramer, lacks all 4 α-globin genes; -results in hydrops fetalis & intrauterine fetal

death- prevalent in Asia and Africa

Blood Dyscrasias Cont’d

• β-thalassemia

- β-thalassemia minor (heterozygote): β-chain is underproduced

- β-thalassemia major (homozygote): β-chain is absent

- in both, fetal hemoglobin production is compensatorily increased but is inadequate

- HbS/β-thalassemia heterozygote has mild to moderate disease

- β-thalassemia major (homozygote) results in severe anemia requiring blood transfusions- Cardiac failure due to 2° hemochromatosis- Marrow expansion skeletal deformities (“crew-cut” on skull x-ray)- Prevalent in Mediterranean popns.

β-thalassemia

Sample Questions

Hereditary Spherocytosis