Oncology

Question 1

A boy has a suspicious lymph node removed.

What is the classic histologic feature of Hodgkin lymphoma seen on lymph node biopsy?

Answer 1

Reed-Sternberg cell
Explanation
The Reed-Sternberg cell is a large cell with multiple or multilobulated nuclei (looks like “owl’s eyes”). Most are of B-cell lineage, but some are also of T-cell lineage.

Question 2

What is the most common type of central nervous system (CNS) tumor in childhood?

Answer 2

Gliomas
Explanation
Gliomas make up 50–60% of all brain tumors and are the most common primary childhood CNS tumors. They can be astrocytomas or gliomas; not all gliomas are malignant, and the most common malignant CNS tumor is medulloblastoma.

Question 3

What is the translocation seen in a majority of patients with Ewing sarcoma?

Answer 3

t(11;22)
Explanation
A majority of patients with Ewing sarcoma have a t(11;22) translocation, while the rest have a t(21;22) translocation.

Question 4

A 15-year-old White male presents with:

Fever
Weight loss
Rib pain
Primary lytic lesion with “onion skinning” of the diaphysis of the right femur on x-ray
What is the most likely diagnosis?

Answer 4

Ewing sarcoma
Explanation
Ewing sarcoma is an undifferentiated sarcoma of the bone. It is more likely to affect the diaphyses of long bones and flat bones (ribs, pelvis). Be sure to differentiate this from osteosarcoma (metaphyseal involvement and “sunburst” pattern on x-ray). Ewing sarcoma is more commonly seen in White individuals.

Question 5

What is the most common type of malignant central nervous system (CNS) tumor in childhood?

Answer 5

Medulloblastoma
Explanation
Medulloblastomas are the most common type of malignant CNS tumor in childhood. They are a type of CNS embryonal tumor and there are 4 molecular subtypes with unique features.

Question 6

Impaired upward gaze
Dilated pupils with better reactivity to accommodation than to light
Retraction or conversion nystagmus with lid retraction
What is the syndrome associated with this triad?

Answer 6

Parinaud syndrome
Explanation
Parinaud syndrome is caused by compression or infiltration of the midbrain tectum, particularly with pineal tumors.

Question 7

What is the most common primary malignant bone tumor in children?

Answer 7

Osteosarcoma
Explanation
Osteosarcoma occurs most often during the adolescent growth spurt, presenting with unilateral pain and swelling—usually in the metaphyseal region of long bones and in the medullary cavity. The most commonly affected site is around the knee (distal femur and proximal tibia). Osteosarcoma is the most common primary malignant bone tumor in children and adolescents overall.

Question 8

An adolescent receives mantle radiation for his Hodgkin lymphoma.

Name a long-term side effect of radiation therapy that affects the vessels of the heart.

Answer 8

Early-onset coronary artery disease
Explanation
Be familiar with the long-term effects of radiation therapy, especially these:
Growth restriction
Hypothyroidism
Early-onset coronary artery disease
Pericardial disease
Pulmonary fibrosis
Increased risk of breast cancer

Question 9

A 15-year-old boy presents with history of injury to his left thigh with subsequent:

Pain and swelling over the metaphyses of his left femur
Nighttime awakening
Palpable mass
“Sunburst” pattern on x-ray
What is the most likely diagnosis?

Answer 9

Osteosarcoma
Explanation
Osteosarcoma typically occurs in the metaphyseal region of long bones, and children commonly think they have injured themselves while playing sports. Differentiate this from Ewing sarcoma, which involves the diaphyses of long bones and flat bones, as well as x-ray findings that show lytic lesions or “onion skinning.”

Question 10

A child presents with:

Nausea and vomiting
Abdominal mass and pain in the ileocecal junction area
Fever
CT scan of the abdomen confirms that the mass is at the ileocecal junction.

What is the most likely diagnosis?

Answer 10

Answer
Burkitt lymphoma
Explanation
Burkitt lymphoma is the most common form of non-Hodgkin lymphoma, with 90% originating from relatively mature B cells in Peyer patches within the GI tract—most commonly at the ileocecal junction. Jaw involvement is very common in the African form, but occurs in only 15% of U.S. cases. Burkitt lymphoma is the fastest growing malignant tumor and can result in life-threatening tumor lysis syndrome.

Question 11

Name the disease associated with hemangioblastomas in the cerebellum, medulla, and spinal cord.

Answer 11

von Hippel-Lindau (VHL) disease
Explanation
VHL disease increases the risk of hemangioblastomas in the central nervous system. It is most often an autosomal-dominant inherited disorder (80%), but 20% of cases have no family connection

Question 12

A 10-year-old boy (who is otherwise completely asymptomatic) presents with:

Bony, nonpainful mass on his distal femur
On x-ray, “stalks” or “broad-based projections” from the surface of the bone, with an associated cartilage “cap” that is ∼ 0.5 cm thick
What is the most likely diagnosis?

Answer 12

Osteochondroma
Explanation
Osteochondroma is a very common benign tumor in children. Most occur in the metaphysis of long bones—particularly the distal femur, proximal humerus, and proximal tibia. Leave these alone unless they cause symptoms, in which case, excise the lesion

Question 13

A 20-month-old presents with ataxia and myoclonic jerking with random eye movements.

What is the most likely diagnosis?

Answer 13

Neuroblastoma
Explanation
Opsomyoclonus (myoclonic jerking and random eye movements) in association with ataxia occurs in about 5% of patients with neuroblastoma and may be the presenting symptom. The most common presentation, however, is a nontender abdominal mass.

Question 14

Maternal breast cancer
Sarcoma in children
Adrenocortical carcinoma
Germline mutations in the p53 gene
CNS tumors: gliomas, ependymomas, and choroid plexus carcinomas
What syndrome presents with these findings?

Answer 14

Li-Fraumeni syndrome
Explanation
Li-Fraumeni syndrome is a familial cancer syndrome associated with an increased risk of gliomas, ependymomas, and choroid plexus carcinomas.

Question 15

What is the most common type of lymphoma to occur in children?n

Answer 15

Non-Hodgkin lymphoma (NHL)
Explanation
NHL outnumbers Hodgkin lymphoma (HL) as the most common type of lymphoma in pediatrics (NHL 60% vs. HL 40%). Males outnumber females 3:1, and lymphomas occur across the age spectrum from younger to older patients. There is a high rate of NHL in children with ataxia telangiectasia, Wiskott-Aldrich syndrome, HIV, and other immunosuppressive diseases.

Question 16

Manifests at < 2 years of age
Markedly enlarged spleen
Modest leukocytosis
Thrombocytopenia
Elevated fetal hemoglobin
Xanthoma
Café au lait spots
Eczema
No Philadelphia chromosome
Monosomy 7 in 30% of patients
Which type of leukemia presents with these findings?

Answer 16

Answer
Juvenile Myelomonocytic Leukemia (JMML)
Explanation
JMML presents as outlined here. There is no blast crisis, but the 5-year survival rate without bone marrow transplant is < 10%. Children with neurofibromatosis Type 1 are at increased risk for JMML.

Question 17

A 17-year-old boy has the following:

Asymptomatic, firm, nontender cervical lymph node (3 × 2 cm in size, noticed by his barber)
No other symptoms
He has no cat exposure, and 1 week of cephalexin therapy has not decreased the size of the gland—if anything, it is slightly larger. He has no new symptoms.

What do you recommend at this point?

Answer 17

Answer
Excisional biopsy of the node
Explanation
This patient is in the age group that is at higher risk for Hodgkin lymphoma. A painless, isolated, enlarging lymph node with no cat exposure or other risk factors unfortunately raises the possibility of Hodgkin’s. Perform an excisional biopsy of the node.

Question 18

Optic chiasm
Carotid arteries
CN 3 (oculomotor nerve)
Pituitary stalk
What type of brain tumor is benign, but because of its invasive growth, commonly impinges on many structures (including those listed above)?

Answer 18

Craniopharyngioma
Explanation
Craniopharyngiomas are benign tumors that are derived from squamous epithelial cells and arise in the suprasellar region. More than 50% of children with craniopharyngioma have visual changes due to optic involvement. Because of pituitary involvement, look for growth failure, short stature, and polydipsia as presenting signs.

Question 19

Wmhat major side effect do you worry about with use of vincristine?

Answer 19

Neuropathy
Explanation
Closely monitor patients on the chemotherapy drug vincristine, and be on the lookout for foot drop, constipation, poor fine motor control, and neuropathic pain.

Question 20

What histologic feature(s) is/are required for the diagnosis of Langerhans cell histiocytosis?

Answer 20

Intra/extracellular staining with CD207 (langerin) or extracellular staining with CD1a
Explanation
Diagnosis is confirmed by finding CD207 (langerin) or CD1a by immunohistochemistry. Birbeck granules are seen on electron microscopy.

Question 21

What major side effect do you worry about with use of doxorubicin?

Answer 21

Cardiomyopathy
Explanation
The anthracycline chemotherapy drugs (doxorubicin or daunorubicin) can cause cardiotoxicity, presenting as cardiomyopathy.

Question 22

What is the most common soft tissue tumor of childhood?

Answer 22

Rhabdomyosarcoma
Explanation
Rhabdomyosarcoma makes up about 5% of all childhood cancers. It arises from the same embryonic mesenchyme as striated skeletal muscle. Mass lesions of the head and neck—including the orbit and parameningeal sites—are the most common location, followed by the genitourinary tract.

Question 23

What is the most common malignancy in infants?

Answer 23

Neuroblastoma
Explanation
Neuroblastoma makes up 8–10% of all childhood cancers and is the most common malignancy in infants. Median age of diagnosis is 22 months of age; the best prognosis is seen in children diagnosed at < 18 months of age. (Acute lymphoblastic leukemia is the single most common childhood malignancy, but its incidence peaks between 2 and 5 years of age.)

Question 24

What is the Philadelphia chromosome translocation?

Answer 24

Answer
t(9;22)
Explanation
The t(9;22) translocation in patients with chronic myeloid leukemia (a.k.a. chronic myelogenous leukemia) is called the Philadelphia chromosome. This results in the juxtaposition of the BCR gene on chromosome 22 with the ABL gene on chromosome 9, causing a fusion gene that encodes for a BCR-ABL abnormal protein tyrosine kinase that drives oncogenesis.

Question 25

What is the most common childhood malignancy?

Answer 25

Answer
Acute lymphoblastic leukemia (ALL)
Explanation
Leukemia is the most common cancer in childhood (25% of pediatric cancers), and ALL in particular is the single most common childhood malignancy (75% of all pediatric leukemia cases). Luckily, ALL is one of the most curable cancers today. Its peak incidence is between 2 and 5 years of age.

Question 26

A 3-year-old presents with:

Fatigue
Pallor
Painful limping
You suspect leukemia.

What is the most common type of leukemia in children?

Answer 26

Acute lymphoblastic leukemia (ALL)
Explanation
ALL can present in many different ways—including fatigue and pallor due to anemia, and painful limping due to bone marrow packed with leukemia blasts. Many children with leukemia present with bone pain, the presence of which can distinguish the pancytopenia of leukemia from the pancytopenia of aplastic anemia. Generalized lymphadenopathy and hepatosplenomegaly are seen in > 50% of patients.

Question 27

Which is the most common posterior fossa tumor of childhood?

Answer 27

Cerebellar astrocytoma
Explanation
Cerebellar astrocytomas (usually low grade, juvenile pilocytic astrocytomas) are the most common posterior fossa tumor of childhood. Patients with these tumors present with clumsiness and unsteadiness of the arms and legs; headaches and vomiting also occur.

Question 28

An adolescent boy presents with:

Anterior mediastinal mass
Nontender cervical and supraclavicular nodes
Hepatosplenomegaly
You suspect non-Hodgkin lymphoma (NHL).

What cell type is this likely originating from?

Answer 28

Thymic T-cell origin
Explanation
NHL tumors that present as mediastinal masses are almost always lymphoblastic lymphomas, and about 80% are of thymic T-cell origin. These are typically seen in adolescent males.

Question 29

What is the most common benign tumor of the liver in childhood?

Answer 29

Hemangioma
Explanation
Hemangioma is the most common benign liver tumor in childhood. Biopsy is not indicated; if there are no symptoms, no therapy is necessary because these lesions eventually regress.

Question 30

What is the most common primary malignant tumor of the kidney in childhood?

Answer 30

Answer
Wilms tumor
Explanation
Wilms tumor (nephroblastoma) is the most common primary malignant tumor of the kidney in childhood. The mean age of diagnosis is 42–47 months for unilateral tumors and 30–33 months for bilateral tumors.

Question 31

A 10-year-old boy presents with unremitting and worsening pain of his proximal left femur (the pain is worse at night). Palpation and range of motion do not worsen the pain; ibuprofen relieves the pain. On x-ray, a round, metaphyseal lucency surrounded by sclerotic bone is noted.

What is the most likely diagnosis?n

Answer 31

Answer
Osteoid osteoma
Explanation
Osteoid osteomas are benign tumors that generally occur between 5 and 20 years of age in males. Pain is temporarily relieved with nonsteroidal antiinflammatory drugs (NSAIDs; pain from osteosarcoma is not relieved with NSAIDs). About 25% cannot be seen on plain x-ray but can be seen on CT scan. Treat by excising the lesion.

Question 32

A child presents with an orbital chloroma and hepatosplenomegaly.

What is the most likely diagnosis?

Answer 32

Acute myeloid leukemia (AML)
Explanation
An orbital or epidural chloroma, which is a localized mass of leukemic cells, may be the 1st clue of AML (a.k.a. acute myelogenous leukemia). Hepatosplenomegaly can sometimes occur, but anemia and thrombocytopenia are almost always present.