Background: Hemophagocytic lymphohistiocytosis (HLH) is an infrequent but life-threatening disease due to excessive immune activation. Secondary HLH can be triggered by infections, autoimmune diseases, and malignant diseases. Streptococcus pneumoniae is a pathogenic bacterium responsible for invasive pneumococcal disease (IPD) such as meningitis and bacteremia. Although the pneumococcal conjugate vaccine (PCV) has led to reductions in IPD incidence, cases of IPD caused by serotypes not included in PCV are increasing. There are few reports of secondary HLH caused by IPD in previously healthy children. We herein report a rare case of a previously healthy boy with secondary HLH complicating IPD of serotype 23A, which is not included in the pneumococcal 13-valent conjugate vaccine (PCV-13). Case presentation: An 11-month-old boy who had received three doses of PCV-13 was hospitalized with prolonged fever, bilateral otitis media, neutropenia and elevated C-reactive protein (CRP) levels. Blood culture on admission revealed S. pneumoniae, leading to a diagnosis of IPD. HLH was diagnosed based on a prolonged fever, neutropenia, anemia, hepatosplenomegaly, hemophagocytosis in the bone marrow, and elevated serum levels of triglycerides, ferritin, and soluble interleukin-2 receptor. He received broad-spectrum antibiotics and intravenous immunoglobulins for IPD and high-dose steroid pulse therapy and cyclosporine A for HLH; thereafter, his fever resolved, and laboratory findings improved. The serotype of the isolated S. pneumoniae was 23A, which is not included in PCV-13. Conclusions: It is important to consider secondary HLH as a complication of IPD cases with febrile cytopenia or hepatosplenomegaly, and appropriate treatment for HLH should be started without delay.

A 3-year-old boy presented to the emergency department with abdominal pain and frequent vomiting. Physical examination was not remarkable, except for slight abdominal tenderness. His mother reported that he had ingested several magnets and abdominal radiography showed seven metallic foreign bodies in line, suggesting the ingestion of multiple magnets (Fig. 1). These seven magnets consisted of a cluster of six magnets and one separated magnet, which indicated that the intestinal wall was sandwiched by these magnets. A cluster of six magnets located in the stomach was removed by emergency endoscopy (Fig. 2a), whereas one separated magnet could not be found because it was not located in the stomach and thus could not be removed by endoscopy. After the removal of six magnets,