Incidental Diagnosis of Oligosymptomatic Bilateral Perirenal Erdheim-Chester Disease during Emergency Investigation for COVID-19 Infection

Abstract

Erdheim-Chester disease (ECD), a rare form of non-Langerhans histiocytosis, is a multisystem disorder. The case reported here refers to a 49-year-old man presenting at the emergency room with respiratory symptoms. While undergoing diagnostic tests for COVID-19 infection, tomography revealed asymptomatic bilateral perirenal tumors, while renal function remained unaltered. ECD was suggested as an incidental diagnosis and confirmed by core needle biopsy. This report provides a brief description of the clinical, laboratory, and imaging findings in this case of ECD. This diagnosis, albeit rare, should be taken into consideration in the context of incidental findings of abdominal tumors to ensure that treatment, when required, is instituted early.

Figure 1

Computed tomography images of the abdomen: (a) before administration of the intravenous iodinated contrast, (b) corticomedullary phase, and (c) coronal reformatted image of the nephrographic phase, showing tissue with soft-tissue density surrounding the renal parenchyma and infiltrating the renal pelvis bilaterally. Note the slight dilatation of the bilateral collecting system resulting from extrinsic compression by the tissue. Positron emission tomography/computed tomography (PET-CT): no radiopharmaceutical uptake is seen on PET-CT as shown in (d) coronal PET, (e) axial PET, and (f) fusion of PET with tomographic image. Percutaneous biopsy confirmed the hypothesis of renal histiocytosis (Erdheim–Chester disease).

Figure 2

Photomicrography. CT-guided core biopsy of the perirenal lesion. (a) Fibrous tissue with infiltrate of plasma cells, lymphocytes, and histiocytes (right) adjacent to renal parenchyma (left) (HE, 40x). (b) Immunohistochemical staining for CD68, highlighting the histiocytic infiltrate. CT: computed tomography.