Bumps on the Neck and Groin of a 2-Year-Old Male

Clinical History Patient: 2-year-old white male. Chief Complaint: Bumps on neck and groin. History of Present Illness: A 2-year-old boy arrived at the emergency department with a 1- to 2-week history of bumps on his neck and groin. He had been referred to the emergency department by his primary care physician (PCP) when the results of an in-office fingerstick blood test revealed a high white blood cell (WBC) count and a low platelet count. The parents of the patient say that he had had bilateral knee pain a few days previously, which had resolved spontaneously, and had had a cough for the past week. The parents mentioned that when their son had started coughing one week prior, they had contacted the PCP and had mentioned the bumps on his neck and his cough. The physician diagnosed the boy as having lymphadenopathy attributed to a viral illness. Medical and Family History: As of this writing, the patient's immunizations are up to date. He experiences seasonal allergies, with symptoms that include itchy eyes and runny nose. His recurrent ear infections have been resolved by pressure-equalization tubes and adenoidectomy. The patient's maternal grandmother and maternal uncle have long QT syndrome. His paternal great-grandfather has a low platelet count (specificity not given). The patient lives with his parents; as of this writing, his mother is currently at 31 weeks' gestation, originally with triplets but currently with twins (one fetus recently died in utero). Physical Examination: During examination to determine the extent of symptoms, abnormalities were found in the respiratory, lymphatic, and musculoskeletal systems. The patient was observed to cough and have leg and knee pain; he also had swollen lymph glands. Laboratory Findings: Table 1, Table 2; Figure 1; Image 1, Image 2, Image 3 Additional Diagnostic Tests: Results of flow cytometric testing indicate an abnormal population in the R2 blast gate. These blasts, which accounted for 40% of the nucleated cells studied, tested positive for B-cell markers CD19 and CD22 and biphenotypic for CD20. The blast cells also tested positive for CD10 and terminal deoxynucleotidyl transferase (TdT).