Case Presentation: A 61 year-old-female presented to an outside institution with worsening exertional dyspnea, chest pressure, and fatigue. Echocardiogram revealed a large pericardial effusion bordering on tamponade which was drained with great improvement of symptoms. CT Chest/Abdomen/Pelvis revealed perirenal soft tissue invasion, which was biopsied. Patient was then referred to our institution for further management; however the perinephric tissue biopsy was lost in transit. Imaging at our institution revealed extensive infiltrative soft tissue coating the aorta that tracked down the vessel along the renal arteries to the retroperitoneal space where it encased both kidneys with a hairy-like appearance. Patient underwent pericardial window placement due to re-accumulation of pericardial fluid. Pericardium was biopsied perioperatively without clear evidence of histiocytosis. Infectious and autoimmune workup was negative. PET scan was obtained revealing bilateral symmetrical hypermetabolic sclerosis of distal femurs and proximal tibias, although patient never reported bone pain. She was found with a right knee medial tibial soft tissue nodule which was biopsied. Immunochemistry of tissue revealed CD68 positivity, S100 negative within histiocytes, CD1a negative. Both the radiologic and histologic findings confirmed the diagnosis of Erdheim-Chester disease. Treatment was started with pegylated interferon-alpha.
Discussion: Erdheim-Chester disease (ECD) is a rare non-Langerhans histiocytic disorder characterized by osteosclerotic lesions of the long bones with or without histiocytic infiltration of extraskeletal tissues. The etiology of ECD is unclear, but is thought to be associated with an intense TH1 immune response or mutation of V600E BRAF.
The most common clinical presentations are bone pain, neurologic features, diabetes insipidus, and constitutional symptoms. Cardiac involvement in one retrospective case series of 37 patients was seen in 57 percent of the patients. Reportedly, 31 percent of ECD-related deaths are secondary to cardiac involvement. The most common cardiac finding is infiltration of the right heart, including pseudo-tumor. Periaortic fibrosis, periarterial infiltration of the coronary arteries, and pericardial effusion are also common.
Diagnosis is based on radiological and histological criteria. Radiographs and 99mTc bone scintigraphs are the typical imaging studies. Bilateral symmetric osteosclerotic lesions are observed on radiographs, while abnormally strong labeling of the distal ends of the long bones are observed on 99mTc bone scintigraphs. Histologically, diagnosis is made with findings of xanthogranulomatous infiltration of tissues by foamy histiocytes with immunohistochemical staining that is CD68 positive, CD1a negative, S-100 negative or low.
Treatment is required at time of diagnosis for symptomatic disease, central nervous system involvement, and evidence of organ dysfunction. Pegylated interferon-alpha is the treatment of choice as it has shown sustainable stabilization of the disease in most cases.
Conclusions: Erdheim-Chester disease is a rare form of non-Langerhans-cell histiocytosis characterized by otosclerosis and substantial highly variable extra-skeletal involvement. The rarity and variability of symptoms at presentation make it a diagnostic challenge.