Clinical features at LCH diagnosis according to BRAFV600Estatus. (A) Prevalence of BRAFV600E in patients with specific clinical characteristics at LCH diagnosis. (B) Prevalence of BRAFV600E in patients with specific types of bone involvement at diagnosis. This figure depicts all patients with osseous lesions, irrespective of single-systemic or multisystemic disease extent. Bones are grouped according to the classification used by the National Cancer Institute. Upper extremity: humerus, radius, ulna, carpals, metacarpals, and phalanges. Shoulder girdle: clavicle and scapula. Pelvic girdle: coxal, innominate, and hip bones (including ilium, ischium, acetabulum, and pubis). Lower extremity: femur, tibia, fibula, patella, tarsals, metatarsals, and phalanges. Spinal column: cervical, thoracic and lumbar vertebrae, sacrum, and coccyx. Thoracic cage: ribs and sternum. CNS-risk lesions are bone lesions affecting the orbital, temporal/mastoid, sphenoidal, zygomatic, or ethmoidal bones, the maxilla, paranasal sinuses, or anterior or middle cranial fossa, according to LCH Study Group definitions.9,34-36 (C) Prevalence of BRAFV600E in patients with specific presentations of SS-skin LCH at diagnosis. Numbers of patients are provided in Table 1 and supplemental Table 3. Dashed lines indicate the prevalence of BRAFV600E in all cases (51%). Statistical tests with P < .05 are shown. ∗P < .05, ∗∗P < .00125. MS, multisystem; SS, single-system; RO, risk organ; UFB, unifocal bone; MFB, multifocal bone; CNS, central nervous system.
