Extracerebral subdural manifestation of Chester-Erdheim disease associated with a giant adenoma of the pituitary.

Chester-Erdheim disease is a rare non-Langerhans histiocytosis, affecting within the CNS mainly the neurohypophyseal unit, the retrobulbar space and the parenchyma of cerebellum, cerebrum and brainstem. Here we present a case of a 55-year-old woman who developed an exophthalmus, edema and dyspnea, finally leading to death 4 months post admission to the hospital. A cMRI showed a retrobulbar fibrosis, a tumor in the sella turcica, and further tumor formation expanding from the pons to the spinal cord, but without involvement of the dural sheet. Autopsy revealed multiple tumors attached to the pituitary gland, the tentorium, and the brainstem as well as a diffuse thickening of the dura. Histologically, the tumor tissue consisted of densely packed lipid-laden foamy macrophages positive for CD68 and intervening fibrillary cords. Interestingly, tumor cells did not infiltrate/affect the parenchyma but showed a strictly extracerebral/ subdural location. In addition, sections of the pituitary tumor revealed a chromophobe giant adenoma of the pituitary gland. As to our knowledge this is the first detailed description of an exceptional case of intracranial CED presenting with strictly extracerebral/subdural tumor masses accompanied by a giant adenoma of the pituitary gland.