A 7-year-old African American girl without significant medical history presented with progressive painless right-sided neck swelling for 2 months. Initially, she experienced fever and sore throat. Physical examination findings demonstrated minimally tender and nonmobile 4-cm right submandibular space swelling. Laboratory examination findings were significant for leukocytosis with neutrophilia (white blood cell count, 19.8 K/μL; neutrophil count, 18.2 K/μL [to convert to ×109/L, multiply by 0.001]), anemia (hemoglobin level, 9.6 g/dL [to convert to g/L, multiply by 10.0]), elevated erythrocyte sedimentation rate (>130 mm/h), and elevated C-reactive protein level (3.1 mg/dL [to convert to mg/L, multiply by 10]). Ultrasonography revealed multiple enlarged hyperemic lymph nodes within the right side of the neck, the largest measuring 3.4 × 2.4 × 2.1 cm in the submandibular space. She was treated with oral antibiotics without improvement. Ultrasonography at 1-month follow-up revealed interval enlargement of the lymph nodes, which appeared rounded in shape, without preservation of internal architecture. The mother reported that the patient lost 3.2 kg in 2 months, without any chills or night sweats, difficulty swallowing or breathing, change in voice, abdominal pain, recent travel, or exposure to animals or pets.