A 12-year-old patient presents with generalized fatigue, gingival enlargement, bleeding gums, and petechiae on the palate. What condition should be suspected first?

Correct answer: D. Leukemia

• A. Idiopathic thrombocytopenic purpura (ITP) causes bleeding and petechiae but not gingival enlargement. ITP is a diagnosis of exclusion; leukemia must be ruled out first.
• B. Infectious mononucleosis causes palatal petechiae, lymphadenopathy, and fatigue but does not typically cause gingival enlargement or the bleeding diathesis seen here.
• C. Drug-induced gingival hyperplasia (phenytoin, nifedipine, cyclosporine) causes enlargement without systemic fatigue, petechiae, or bleeding diathesis. A 12-year-old's drug history would need to be reviewed, but systemic features point away from this.
• D. CORRECT. The combination of gingival enlargement, bleeding/petechiae (suggesting thrombocytopenia from marrow infiltration), and systemic fatigue in a child is classic for acute leukemia (typically acute lymphoblastic leukemia - ALL in this age group). Leukemic infiltration of the gingiva produces tissue enlargement, and thrombocytopenia from marrow failure causes bleeding and petechiae. This is a MEDICAL EMERGENCY requiring immediate referral.