Mycoplasma pneumoniae causes various extra-pulmonary complications. As a rare but fatal hematological complication, hemophagocytic lymphohistiocytosis (HLH) can be observed in children with M. pneumoniae infection. We report a case of a 6-year-old girl with HLH who was initially presumed to have macrolide-refractory M. pneumoniae pneumonia. Despite the combination treatment of antimicrobial and anti-inflammatory agents, she showed persistent fever, hepatosplenomegaly, and thrombocytopenia. Secondary HLH associated with M. pneumoniae should be considered if unexplained clinical deterioration is noted in children with macrolide-refractory M. pneumoniae pneumonia.

Mycoplasma pneumoniae causes various extra-pulmonary complications. As a rare but fatal hematological complication, hemophagocytic lymphohistiocytosis (HLH) can be observed in children with M. pneumoniae infection. We report a case of a 6-year-old girl with HLH who was initially presumed to have macrolide-refractory M. pneumoniae pneumonia. Despite the combination treatment of antimicrobial and anti-inflammatory agents, she showed persistent fever, hepatosplenomegaly, and thrombocytopenia. Secondary HLH associated with M. pneumoniae should be considered if unexplained clinical deterioration is noted in children with macrolide-refractory M. pneumoniae pneumonia.

In Turner syndrome (TS), 45,X/47,XXX mosaicism is a rare genotype. Due to its low frequency, the clinical features and prognosis are not clearly known. A 10-year-old girl was diagnosed with 45,X/47,XXX mosaicism TS and presented with short stature. She did not show any other TS phenotypic features, except for short stature, and developed spontaneous puberty and menarche, although she had unilateral ovarian agenesis. She achieved a significant growth improvement following growth hormone treatment. Since 45,X/47,XXX mosaic TS shows different gonadal function from that of classic TS, it is necessary to conduct surveillance for premature ovarian insufficiency.