Nokea
Thrombocytopenia is absent in:
- A. DIC
- B. Wiskott Aldrich syndrome
- C. Henoch Schonlein purpura
- D. myelosclerosis
Correct Answer: C
Rationale: Thrombocytopenia is absent in Henoch Schonlein purpura because it primarily involves vasculitis, not platelet destruction or consumption. In DIC (A), there is widespread activation of coagulation leading to thrombocytopenia. Wiskott Aldrich syndrome (B) is characterized by low platelet counts due to defective platelet function. Myelosclerosis (D) is a bone marrow disorder causing decreased platelet production, leading to thrombocytopenia.
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Which of the following best characterizes the function of ferroportin in iron metabolism?
- A. A form of storage iron in intestinal mucosal cells
- B. A transport protein in the plasma
- C. A receptor protein on the surface of erythroid progenitors
- D. Transmembrane iron exporter
Correct Answer: D
Rationale: The correct answer is D: Transmembrane iron exporter. Ferroportin is a transmembrane protein that functions as an iron exporter, allowing iron to move out of cells. This is crucial in iron metabolism as it facilitates the release of iron from cells into the bloodstream for transport to other tissues.
A: A form of storage iron in intestinal mucosal cells - This is incorrect as ferroportin is not involved in storing iron in cells.
B: A transport protein in the plasma - This is incorrect as ferroportin is not primarily a plasma protein but rather a transmembrane protein.
C: A receptor protein on the surface of erythroid progenitors - This is incorrect as ferroportin is not a receptor protein but an exporter protein.
A 7-year-old boy presents with recent onset of vomiting and lethargy. Blood smear shows increased neutrophils with a left shift and 8% abnormal cells. Bone marrow contains 60% of the same cells. Flow cytometry shows that the cells are TdT–, CD10+, CD19+, CD20+, sIg+. What is the most likely diagnosis?
- A. Burkitt leukemia/lymphoma
- B. B-cell acute lymphoblastic leukemia (ALL)
- C. T-cell ALL
- D. Hematogones
Correct Answer: A
Rationale: The correct answer is A: Burkitt leukemia/lymphoma. This diagnosis is supported by the presence of abnormal cells that are CD10+, CD19+, CD20+, sIg+, which are characteristic of Burkitt lymphoma. The absence of TdT– indicates that it is not T-cell ALL. B-cell ALL would typically show TdT positivity. Hematogones are immature B-cell precursors commonly seen in the bone marrow of healthy children and do not typically present with the described clinical picture. The high percentage of abnormal cells in both blood and bone marrow, along with the specific immunophenotype, point towards Burkitt leukemia/lymphoma.
You are seeing a 12-year-old boy in the survivorship program who presented at 2 years old with a desmoplastic nodular medulloblastoma. You note the child recently underwent germline genetic testing and was found to have nevoid basal cell carcinoma syndrome. In which gene is the child most likely to have a pathogenic variant?
- A. PTEN
- B. CDKN2A
- C. SUFU
- D. SMARCB1
Correct Answer: C
Rationale: Rationale: The correct answer is C: SUFU. Nevoid basal cell carcinoma syndrome, also known as Gorlin syndrome, is associated with pathogenic variants in the SUFU gene. SUFU is a tumor suppressor gene involved in the sonic hedgehog signaling pathway, which plays a role in medulloblastoma and basal cell carcinoma development. PTEN (A) is associated with Cowden syndrome, CDKN2A (B) with familial atypical multiple mole melanoma syndrome, and SMARCB1 (D) with rhabdoid tumor predisposition syndrome, but not specifically linked to nevoid basal cell carcinoma syndrome.
Dohle bodies are patches of dilated endoplasmic reticulum that appear as cerulean blue cytoplasmic puddles. These findings are mostly seen in
- A. Chronic myeloid leukemia
- B. Leukemoid reaction
- C. Chediak-Higashi syndrome
- D. Infectious mononucleosis
Correct Answer: D
Rationale: Step-by-step rationale for why choice D (Infectious mononucleosis) is correct:
1. Infectious mononucleosis is caused by the Epstein-Barr virus.
2. Dohle bodies are seen in the peripheral blood of patients with infectious mononucleosis.
3. These bodies represent aggregates of rough endoplasmic reticulum in neutrophils.
4. The appearance of Dohle bodies is attributed to the viral infection in infectious mononucleosis.
Summary:
A: Chronic myeloid leukemia - Dohle bodies are not typically seen in this condition.
B: Leukemoid reaction - Dohle bodies are not specific to a leukemoid reaction.
C: Chediak-Higashi syndrome - This syndrome is characterized by giant granules in neutrophils, not Dohle bodies.
A 13-year-old Hispanic girl is found to have a WBC count of 6,500/mm3 with 40% Auer rod–containing granular blasts that, by flow cytometry, express very bright CD33 but are negative for human leukocyte antigen–DR isotype (HLA-DR). She is oozing blood around her peripheral IV site. Coagulation studies reveal an international normalized ratio (INR) of 3.4, a fibrinogen of 170, and a markedly elevated D-dimer. Marrow aspirate shows nearly 90% blasts with a similar morphology. You send the marrow to the fluorescence in situ hybridization (FISH) lab and request STAT testing for the most likely recurrent genetic abnormality based on the clinical presentation. How do you plan to initiate therapy?
- A. Perform a lumbar puncture to determine leukemic involvement, then proceed with induction chemotherapy.
- B. Begin therapy with all-trans retinoic acid (ATRA) immediately while aggressively managing coagulopathy with blood product support.
- C. Start dexamethasone and hydroxyurea immediately while aggressively managing coagulopathy with blood product support.
- D. Start induction chemotherapy, obtain HLA typing, and start a donor search because of the poor prognosis associated with this leukemic phenotype.
Correct Answer: B
Rationale: The correct answer is B: Begin therapy with all-trans retinoic acid (ATRA) immediately while aggressively managing coagulopathy with blood product support. The patient's presentation is consistent with acute promyelocytic leukemia (APL), indicated by the presence of Auer rod-containing blasts, very bright CD33 expression, and coagulopathy (elevated INR, low fibrinogen, elevated D-dimer). APL is associated with a specific genetic abnormality involving the PML-RARA fusion gene. ATRA is the mainstay of induction therapy for APL as it induces differentiation of leukemic promyelocytes. Aggressive management of coagulopathy is crucial to prevent life-threatening bleeding complications.
Incorrect answers:
A: Performing a lumbar puncture is not necessary at this stage as the patient's symptoms and laboratory findings point towards APL, not central nervous system involvement.
C: Dexamethasone and hydroxyurea are not