S2620 Cloudy With a Chance of Histocyte Showers: A Case Report Involving Erdheim-Chester Disease

Abstract

INTRODUCTION: Erdheim-Chester Disease (ECD) is a rare non-Langerhans histiocytic disorder that has a very low prevalence, with less than 1000 cases reported in the US. ECD can affect multiple organ systems, and in over 90% of ECD cases, histiocytes tend to deposit in skeletal muscle or bone. Gastrointestinal involvement is exceedingly rare, and we present a case where mass deposits of histiocytes were noted at a visceral level. CASE DESCRIPTION/METHODS: A 56-year-old Hispanic male presented with two years of progressive abdominal discomfort and distention, weight gain of 25 pounds, and dyspnea on exertion. He also noticed enlarging masses across his stomach. On physical examination, firm abdominal masses were noted in bilateral upper quadrants, as well as bilateral pitting edema. Other than hypoalbuminemia, his initial lab testing, including LFTs, were unremarkable. CT scans showed invasive perirenal masses, measuring 30.4 × 19.0 × 38.4 cm on the right and 26.2 × 18.9 × 37.0 cm on the left and multiple sclerotic lesions. Additionally, nodular hepatic hypodensities were noted. Overall, these findings were concerning for an infiltrative process. An echocardiogram showed a pericardial effusion and compression of the IVC and hepatic veins by these masses. Biopsies confirmed the diagnosis of BRAF non-mutated ECD and his tumor markers were positive for CD68, CD34, and Vim. He began treatment with interferon-alpha and surveillance scans thereafter have revealed a gradual decline in size of these masses. DISCUSSION: Classic radiological and histological features of this rare disorder have been identified, but the clinical spectrum shows an extensive variation, ranging from asymptomatic organ infiltration to complete organ failure. The diagnosis of ECD was challenging, as he presented with nonspecific symptoms, including abdominal discomfort, weight gain, and evidence of malnutrition with hypoalbuminemia. Although ECD typically presents with bone pain due to sclerotic lesions, our patient was asymptomatic from this standpoint. It is uncommon to see deposition in renal and hepatic tissue and it is interesting that he had normal lab tests; this is an indication that lab findings may not preclude organ involvement in ECD. In cases like this, it reminds clinicians to have a wide differential diagnosis when approaching abdominal masses.Figure 1.: CT Abdomen (sagittal view) showing massive extension of tissue into the abdomen.Figure 2.: CT Abdomen (axial view) showing perirenal proliferation.Figure 3.: CT Abdomen (axial view) showing liver hypodensities.