Nonneurologic disease manifestations in ALK-positive histiocytosis patients from Group 1B. (A-D) Fluorodeoxyglucose PET-CT images showing bilateral hypermetabolic long bone involvement, reminiscent of ECD, with objective metabolic response in Case 11 after 12 months of crizotinib. (E) Sagittal image of the contrast-enhanced MRI scan of the spine showing multiple hyperintense lesions in the vertebral bodies. (F-G) Axial MRI image (F) and lateral conventional radiograph (G) showing skull lesions in 2 children, with an appearance reminiscent of LCH. (H-K) Axial CT images showing nodular pulmonary involvement in 3 pediatric cases. (L) Photograph of the right axilla of an adult with a brown maculopapular exanthema that coalesces into plaques and predominates in the axillae and flanks, reminiscent of xanthoma disseminatum. (M) Photograph showing 1 of multiple scalp skin lesions in a child, which can also be observed on the MRI of the head (Figure 4A). (N) Ultrasound image demonstrating round, hypoechoic lesions in both lobes of the thyroid gland. (O-P) Axial T2-weighted (O) and diffusion-weighted (P) pelvic MRI images showing a cervical tumor with restricted diffusion in a child that presented with menorrhagia and irregular vaginal bleeding. (Q-R) Axial PET-CT images showing hypermetabolic focal lesions in the liver and pancreas (Q) and in the breast (R). (S) Coronal CT image showing a focal lesion in the left kidney.