gms | German Medical Science

Objective: Mass lesions within the brain stem constitute a diagnostic and therapeutic challenge. Even a stereotactic biopsy is associated with a high incidence of secondary neurological deficits. We report the diagnostic work-up and consecutive therapy of a young patient with a massive brain stem lesion due to Erdheim-Chester disease (ECD).

Methods: A 37-year-old male patient presented to our department with a history of progressive exophthalmus, dysarthria and ataxia. Four years before, he had undergone ureteral stenting for hydronephrosis of unknown origin. MRI demonstrated a mass lesion within the pons and the right cerebellar peduncle with inhomogeneous contrast enhancement. The pituitary stalk appeared thickened. Intraorbitally, there was a mass above the rectus superior muscle. Laboratory work-up revealed a hyperprolactinemia, an insufficiency of the cortico- and somatotropic axes, a peripheral hypogonadism and hypothyreodism. The CT of thorax and abdomen demonstrated a retroperitoneal mass with constriction of the vessels and compression of both ureters. The radiographs of the long bones demonstrated a sclerosis.

Results: Because of the exophthalmus and for histological examination, we performed a decompression of the lateral orbital wall with subsequent biopsy of the intraorbital mass. The periorbital fascia was substantially thickened and had the consistency of rubber-like material. Histology confirmed fibrosis with infiltration by foam histiocytes. We initiated an immunomodulatory therapy with corticoids and interferon. One year later, the patient had improved clinically, and the involvement of the brain stem has decreased substantially.

Conclusions: The differential diagnosis of intracranial plus intraorbital lesions comprises lymphoma, sarcoidosis and Langerhans histiocytosis. In the view of the very specific combination with retroperitoneal fibrosis, we considered ECD, a lipogranulomatous non-Langerhans histiocytosis, the most probable diagnosis. A careful clinical and radiological work-up together with an extracerebral biopsy resulted in the correct diagnosis and an effective therapy thereby avoiding a hazardous brainstem biopsy.