PMON110 Panhypopituitarism as a Rare Presentation of Erdheim – Chester disease (ECD) in an Adolescent Patient

Abstract

Abstract Background Erdheim-Chester disease (ECD) is a rare multisystemic histiocytic disorder. Only a dozen pediatric cases are reported. Here, we present a case of ECD in a pediatric patient who presented with short stature and delayed puberty. Clinical Case A 14-year-old male with history of autism and ADHD presented with short stature and pubertal delay. He grew along the 40th percentile until age 7 years when growth velocity declined. On exam, his height was 145.6 cm (0.98%ile, z-score -2.34), weight was 55.6 kg (63.19%ile, z-score 0.34), and testicular size was 5-6 mL. He had increased thirst and episodes of bedwetting since age 7. Bone age was delayed at 11 years 6 months. Further workup was recommended, but family was lost to follow up. At 16, he returned with continued poor growth, polydipsia, and nocturia. Height was 153 cm (0.26%ile, z-score -2.80), weight 61.1 kg (40%ile, z-score -0.25). Labs revealed IGF-BP3 2.8mcg/mL(3.1-8.9), IGF-1 35ng/mL(245-522), LH 1.2mIU/mL(0.29-4.77), and total testosterone <7.0 ng/dL(250-1100). Prolactin, cortisol, thyroid, and karyotype were normal. Growth hormone (GH) stimulation test confirmed GH deficiency. He was referred to oncology clinic when a brain MRI revealed a nodular enhancing suprasellar mass extending from the third ventricular floor to the dorsum sella along the pituitary stalk and rounded sclerotic lesion in the frontal bone. Biopsy of the suprasellar lesion was remarkable for foamy histiocytes positive for CD68, negative for S100 and CD1a, an eosinophilic cell background highlighted by S100 and synaptophysin, SALL4 negative. A diagnosis of xanthomatous hypophysitis was made. Additionally, lab studies confirmed diabetes insipidus (DI), treated with DDAVP. Growth hormone was trialed for 2 weeks, but he developed acute pancreatitis, so it was discontinued. He subsequently developed recurrent pancreatitis of unclear etiology requiring frequent hospitalization with development of insulin-dependent diabetes mellitus due to pancreatic damage. He was lost to follow up for 12 months after leaving home at age 18. He returned to our institution after incidental findings of 7th right rib expansile lytic bony lesions on abdominal CT during a pancreatitis admission. Biopsy of the rib lesion was positive for a BRAF-V600E mutation. Skeletal survey revealed new multiple small lytic skull lesions. Repeat brain MRI demonstrated new calvarial lesions, increased suprasellar mass. Chest CT scan showed a micronodular pattern with mediastinal lymph node enlargement. PET confirmed widespread multifocal FDG hypermetabolic lesions. Final diagnosis of ECD was made; he was started on targeted therapy with Vemurafenib, a BRAF inhibitor. Conclusion Erdheim-Chester disease (ECD) is a non-Langerhans cell histiocytosis, which rarely affects pediatric patients who present with bone pain and DI; however, here we present a case of ECD in an adolescent with short stature and multiple pituitary deficiencies to highlight the varied presentation of the disorder. Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.