Brain Pathology Case of the Month - August 2008

Contributed by Naomi Arakaki, MD1; Miguel A. Riudavets, MD1; Andrés Cervio, MD2; Marcelo Ferreira, MD2; Gustavo Sevlever, MD, PhD1
Departments of 1Neuropathology, and 2Neurosurgery. Institute for Neurological Research, FLENI. Buenos Aires, Argentina.


A 60-year old woman with past medical history of diabetes, systemic hypertension and diminished visual acuity since early infancy presented with progressive visual loss of the left eye occurring over 24 months prior to consultation. Physical examination revealed a blind left eye with atrophy of the optic papilla. No lymphadenopathies, fever, or weight loss were detected. On magnetic resonance imaging (MRI), an extra-axial mass, hypointense on T2-weighted scans, hyperintense on T1-weighted scans, with contrast enhancement along the posterior aspect of the left optic nerve cranial entrance, measuring 1.8 x 3 cm (Figures 1, 2, and 3) was visualized. A left frontotemporal craniotomy was performed and a pink-yellow soft mass was resected in its entirety. No evidence of brain invasion or involvement was found. Even though a preoperative MRI angiography (to rule out a potential aneurysm) was negative, the lesion bled during the procedure, and an intraoperative digital angiogram was done which was also negative for aneurysm.


Macroscopically, the surgical specimen tissue was whitish-yellow, lobulated, elastic, and measured 2.5 cm in diameter. Intraoperative pathology examination revealed monomorphic cells distributed in sheets or clusters interspersed with eosinophils, lymphocytes and occasional neutrophils, with cells that had histiocytic characteristics imparted by clear cytoplasm and prominent nuclei and nucleoli. Based on the lesion histology, an intraoperative diagnosis of "histiocytic lesion, not otherwise specified" was reached. Permanent sections showed xanthomatous histiocytes with large nuclei displaying prominent nucleoli distributed in small lobules or sheets. Occasional xanthomatous cells displayed multinucleation; however, typical Touton giant cells were not visible. The inflammatory component was composed of lymphocytes, plasmocytes, neutrophils and eosinophils (Figure 4). Tumor cells were immunoreactive for CD68 (Figure 5), occasionally for S100 (Figure 6), but not for CD1a. (Figure 7).


International Society of Neuropathology