Question

The most common malignant cause for bilateral proptosis in children is?

• A. Lymphoblastic lymphoma
• B. Rhabdomyosarcoma
• C. Acute lymphoblastic leukaemia (ALL)
• D. Acute myeloid leukaemia (AML)

Hint:

Bilateral orbital chloroma (granulocytic sarcoma) is the malignant marker, and it belongs to AML.

Answer 1

The Correct Option is D

Step 1: Focus on two qualifiers. The cause must be both malignant and a cause of bilateral proptosis in children.
Step 2: Link bilateral proptosis to leukaemic deposits. The classic malignant cause of bilateral orbital proptosis in a child is a chloroma (granulocytic sarcoma), which is a solid orbital deposit of myeloid leukaemic cells. Chloromas are a feature of acute myeloid leukaemia (AML).
Step 3: Connect chloroma to AML. Because the chloroma is composed of immature myeloid (granulocytic) cells, its presence implies AML; bilateral orbital chloromas are a well-known presentation of childhood AML.
Step 4: Exclude the others. Rhabdomyosarcoma is the commonest primary orbital malignancy of childhood but is usually unilateral. ALL is the commonest childhood leukaemia overall, yet orbital chloromas (and hence bilateral proptosis) are characteristic of the myeloid type. Lymphoblastic lymphoma is far less common as a cause of bilateral childhood proptosis.
Conclusion: Bilateral proptosis from orbital chloroma is the marker of AML, making AML the answer.