A rare case of Langerhans cell histiocytosis (LCH) combined with Erdheim-Chester disease (ECD) in the tibia is presented. A 55-year-old female patient experienced a six-month history of left lower leg pain of unknown origin, which progressively worsened over the past month and was accompanied by restricted mobility. Radiographic imaging revealed patchy, mixed-density shadows within the medullary cavities of the middle and lower segments of both tibiae and fibulae. Magnetic resonance imaging (MRI) showed extensive abnormal signal areas in the lower segments of the left tibia and fibula, as well as in the left talus and calcaneus. Positron emission tomography-computed tomography (PET-CT) demonstrated significantly increased diffuse radioactive uptake in the middle and lower segments of both femora, the upper and lower segments of the tibiae, the bilateral talus, the distal radius, and symmetrical uptake in the bilateral elbow joints. Additionally, mild radionuclide uptake was observed in the bilateral clavicles and the upper segment of the right femur. The initial diagnosis suggested a space-occupying lesion in the tibia with a suspicion of ECD. Histopathological examination of a biopsy from the left tibial lesion indicated a histiocytic proliferative disorder. After a multidisciplinary consultation, a definitive diagnosis of LCH with fibrous hyperplasia and extensive infiltration of foam cells, along with scattered multinucleated giant cells, was established. The presence of the BRAFV600E mutation further supported the concurrent diagnosis of ECD. Subcutaneous interferon-α therapy was initiated. Two years later, pulmonary lesions were identified. Computed tomography (CT) revealed multiple round nodules in both lungs, chronic inflammatory changes, and fibrous cord-like lesions. Consequently, interferon treatment was discontinued, and oral vemurafenib was administered. After three years of follow-up, chest CT demonstrated a significant reduction in chronic inflammatory lesions and fibrous cords, along with a decrease in nodule size. Currently, after four years of continuous follow-up, the patient remains in stable condition, experiences no significant discomfort, and continues to receive vemurafenib maintenance therapy. A review of the literature suggests that the co-occurrence of LCH and ECD is rare, often leading to misdiagnosis or delayed diagnosis. While no standardized treatment protocol exists, patients harboring the BRAFV600E mutation may benefit from BRAF inhibitors such as vemurafenib.

A rare case of Langerhans cell histiocytosis (LCH) combined with Erdheim-Chester disease (ECD) in the tibia is presented. A 55-year-old female patient experienced a six-month history of left lower leg pain of unknown origin, which progressively worsened over the past month and was accompanied by restricted mobility. Radiographic imaging revealed patchy, mixed-density shadows within the medullary cavities of the middle and lower segments of both tibiae and fibulae. Magnetic resonance imaging (MRI) showed extensive abnormal signal areas in the lower segments of the left tibia and fibula, as well as in the left talus and calcaneus. Positron emission tomography-computed tomography (PET-CT) demonstrated significantly increased diffuse radioactive uptake in the middle and lower segments of both femora, the upper and lower segments of the tibiae, the bilateral talus, the distal radius, and symmetrical uptake in the bilateral elbow joints. Additionally, mild radionuclide uptake was observed in the bilateral clavicles and the upper segment of the right femur. The initial diagnosis suggested a space-occupying lesion in the tibia with a suspicion of ECD. Histopathological examination of a biopsy from the left tibial lesion indicated a histiocytic proliferative disorder. After a multidisciplinary consultation, a definitive diagnosis of LCH with fibrous hyperplasia and extensive infiltration of foam cells, along with scattered multinucleated giant cells, was established. The presence of the BRAFV600E mutation further supported the concurrent diagnosis of ECD. Subcutaneous interferon-α therapy was initiated. Two years later, pulmonary lesions were identified. Computed tomography (CT) revealed multiple round nodules in both lungs, chronic inflammatory changes, and fibrous cord-like lesions. Consequently, interferon treatment was discontinued, and oral vemurafenib was administered. After three years of follow-up, chest CT demonstrated a significant reduction in chronic inflammatory lesions and fibrous cords, along with a decrease in nodule size. Currently, after four years of continuous follow-up, the patient remains in stable condition, experiences no significant discomfort, and continues to receive vemurafenib maintenance therapy. A review of the literature suggests that the co-occurrence of LCH and ECD is rare, often leading to misdiagnosis or delayed diagnosis. While no standardized treatment protocol exists, patients harboring the BRAFV600E mutation may benefit from BRAF inhibitors such as vemurafenib.

Brain iron deposition has been proposed to play an important role in the pathophysiology of Alzheimer disease (AD).The aim of this study was to investigate the correlation of brain iron accumulation with the severity of cognitive impairment in patients with AD by using quantitative MR relaxation rate R2' measurements.Fifteen patients with AD,15 age- and sex-matched healthy controls,and 30 healthy volunteers underwent 1.5T MR multi-echo T2 mapping and T2* mapping for the measurement of transverse relaxation rate R2'(R2'=R2*-R2).We statistically analyzed the R2' and iron concentrations of bilateral hippocampus (HP),parietal cortex (PC),frontal white matter (FWM),putamen (PU),caudate nucleus (CN),thalamus (TH),red nucleus (RN),substantia nigra (SN),and dentate nucleus (DN)of the cerebellum for the correlation with the severity of dementia.Two-tailed t-test,Student-Newman-Keuls test (ANOVA) and linear correlation test were used for statistical analysis.In 30 healthy volunteers,the R2' values of bilateral SN,RN,PU,CN,globus pallidus (GP),TH,and FWM were measured.The correlation with the postmortem iron concentration in normal adults was analyzed in order to establish a formula on the relationship between regional R2' and brain iron concentration.The iron concentration of regions of interest (ROI) in AD patients and controls was calculated by this formula and its correlation with the severity of AD was analyzed.Regional R2' was positively correlated with regional brain iron concentration in normal adults (r=0.977,P＜0.01).Iron concentrations in bilateral HP,PC,PU,CN,and DN of patients with AD were significantly higher than those of the controls (P＜0.05); Moreover,the brain iron concentrations,especially in parietal cortex and hippocampus at the early stage of AD,were positively correlated with the severity of patients' cognitive impairment (P＜0.05).The higher the R2' and iron concentrations were,the more severe the cognitive impairment was.Regional R2' and iron concentration in parietal cortex and hippocampus were positively correlated with the severity of AD patients' cognitive impairment,indicating that it may be used as a biomarker to evaluate the progression of AD.

Brain iron deposition has been proposed to play an important role in the pathophysiology of Alzheimer disease (AD). The aim of this study was to investigate the correlation of brain iron accumulation with the severity of cognitive impairment in patients with AD by using quantitative MR relaxation rate R2' measurements. Fifteen patients with AD, 15 age- and sex-matched healthy controls, and 30 healthy volunteers underwent 1.5T MR multi-echo T2 mapping and T2* mapping for the measurement of transverse relaxation rate R2' (R2'=R2*-R2). We statistically analyzed the R2' and iron concentrations of bilateral hippocampus (HP), parietal cortex (PC), frontal white matter (FWM), putamen (PU), caudate nucleus (CN), thalamus (TH), red nucleus (RN), substantia nigra (SN), and dentate nucleus (DN) of the cerebellum for the correlation with the severity of dementia. Two-tailed t-test, Student-Newman-Keuls test (ANOVA) and linear correlation test were used for statistical analysis. In 30 healthy volunteers, the R2' values of bilateral SN, RN, PU, CN, globus pallidus (GP), TH, and FWM were measured. The correlation with the postmortem iron concentration in normal adults was analyzed in order to establish a formula on the relationship between regional R2' and brain iron concentration. The iron concentration of regions of interest (ROI) in AD patients and controls was calculated by this formula and its correlation with the severity of AD was analyzed. Regional R2' was positively correlated with regional brain iron concentration in normal adults (r=0.977, P<0.01). Iron concentrations in bilateral HP, PC, PU, CN, and DN of patients with AD were significantly higher than those of the controls (P<0.05); Moreover, the brain iron concentrations, especially in parietal cortex and hippocampus at the early stage of AD, were positively correlated with the severity of patients' cognitive impairment (P<0.05). The higher the R2' and iron concentrations were, the more severe the cognitive impairment was. Regional R2' and iron concentration in parietal cortex and hippocampus were positively correlated with the severity of AD patients' cognitive impairment, indicating that it may be used as a biomarker to evaluate the progression of AD.