Disseminated Intra-abdominal and Pelvic Abscesses Caused by Streptococcus pneumoniae and Staphylococcus epidermidis in a Previously Healthy Adolescent.

A 14-year-old healthy boy, initially treated for presumed muscle strain, developed progressive left leg pain, a groin mass, and a 30-pound weight loss over six weeks. Labs showed leukocytosis, anemia, thrombocytosis, and elevated inflammatory markers. CT revealed multiloculated pelvic and iliopsoas abscesses with sacroiliac septic arthritis, osteomyelitis, and epidural extension. He underwent a laminectomy, surgical and CT-guided drainage, and prolonged targeted antibiotics. Cultures grew Streptococcus pneumoniae and Staphylococcus epidermidis. Extensive workup for immunodeficiency, Crohn's disease, and malignancy was negative. Atypical invasive infection should be considered even in the absence of traditional risk factors. Early imaging, source control, and prolonged antimicrobial therapy are critical in managing complex deep-seated abscesses.