Langerhans cell histiocytosisBy mahyarHistory: 30 year old male with painful scalp mass Findings:
:: CT 1 ::NECT: lytic defect
:: CT 2 ::NECT: Calvarium, lytic defect, small soft tissue mass
:: MRI 1 ::-T2W :Soft tissue mass at site of bony lysis(Soft tissue masses show slight hyperintensity) Discussion: Proliferation of Langerhans cell histiocytes forming granulomas within any organ system. - Best diagnostic clue: - Skull : sharply marginated lytic skull defect with beveled margins. -Mastoid : geographic destruction, soft tissue mass. -Brain : thick enhancing infundibulum, absent posterior pituitary bright spot. -Location: -Skull: -Calvarium is most common bony site involved, especially prevalent in frontal, parietal bones, also mastoid portion of temporal bone, mandible, orbit, facial bones. -Brain : pituitary infundibulum, hypothalamus. -Size: -Skull and facial bones: Lesions grow fast, moderate soft tissue mass common. - Pituitary infundibulum: Small lesions due to early endocrine dysfunction (DI). -Radiography - Calvarium: Well defined lytic lesion, beveled edge, lack of marginal sclerosis with or without Button sequestra or sclerotic margins when healing. -CT Findings -NECT - Calvarium : lytic defect, beveled (inner table>outer table), small soft tissue mass. - Mastoid : bone destruction, often bilateral, soft tissue mass. -Brain : thickened pituitary stalk. -CECT: -Calvarium => enhancing soft tissue in lytic defect. -Mastoid => soft tissue mass variably enhances. -Brain => enhancing, thick pituitary stalk, ± hypothalamic mass or enhancement. MR Findings: -TIWI -Soft tissue mass at site of bony lysis - Variable, T1 shortening if LCH lesion is proliferative (lipid laden macrophages). -Imaging Recommendations - Best imaging tool: -Skull: NECT -Mastoid disease: CECT - Brain: MRI with contrast -Protocol advice: - Skull: Bone algorithm - Suspected mastoid LCH: CECT, axial and coronal. - Brain MR: Patient with diabetes insipidus. - Pituitary: Small FOV, thin section, no gap, sagittal and coronal Tl imaging with contrast. -If initial study is normal, repeat in 2-3 months. -Etiology: Uncertain: Inflammatory ?neoplastic? - Epidemiology - Affects 4 per 1 million. - Peak age at onset 1 year (isolated), 2-5 years (multifocal disease). - Inverse relation between severity of involvement and age. - 50% LCH cases are monostotic. - Familial LCH < 2%. - Bone lesions are most common manifestations of LCH in 80-95% of children with LCH. Differential diagnosis: -Skull normal variants -Surgical defects: burr holes, CSF shunts and complications -Metastasis -Epidermoid Cyst -Plasmacytoma - Hemangioma -Dermoid Cyst -Leptomeningeal cyst Diagnosis confirmation: Surgery / Histo Category: Other Region / Organ: Head-Bones Etiology: unknown References: DIAGNOSTIC IMAGING BRAIN Anne G. Osborn, [et al]. Get more for Langerhans cell histiocytosis Peer-reviewed resources Literature  More publications about Langerhans cell histiocytosisChallenge yourself with the case quiz! |