9/27/2005 Case 2: Atypical teratoid/rhabdoid tumor

Clinical History:

A 56 year old woman with visual difficulty of new onset occurring while visiting her daughter from Nigeria. An MRI showed a large intra- and supra-sellar mass, protruding into the third ventricle and splaying apart the two halves of the thalamus. Two attempts at resection were made, one trans-sphenoidally and then sub-frontally, but with negligible clinical improvement. MRI showed a large portion of the center of the tumor had been removed but the outer portions had not collapsed into the central cavity. Immunostains did not support a diagnosis of pituitary adenoma. A plethora of stains were negative, with focal EMA and diffuse vimentin positivity being the only positives. The case was sent for consultation.

Diagnostic Notes:

The circulated slides showed a tumor with small to medium size cells, embedded in a matrix with fibrous tissue and perhaps some more cartilage-like foci. Mitotic figures were numerous. The pattern provoked differential diagnoses of chordoma, chordoid meningioma, chondrosarcoma, and, from the consultant (Dr Scheithauer) metastatic carcinoma.

The patient did poorly despite a V-P shunt and died. At autopsy there were metastatic deposits in the pleura and peritoneum, apparently spread there via the shunt. The tumor was widely disseminated in the CNS, including surrounding the spinal cord and brainstem. The autopsy tumor tissues were vimentin +, GFAP +, EMA +, and AE3 + (there was discussion as to whether this reflected true keratin expression or a cross-reaction with GFAP). Some larger cells had rhabdoid features and an INI-l (BAF47) immunostain was negative in the tumor cell nuclei but positive in normal brain cells. Thus the diagnosis is one of Atypical Teratoid/Rhabdoid Tumor . (ATRT) , occurring here in an adult.

Further discussion noted that while originally described in children under 3 (and mostly under 18 months) cases in older children and adults were now well-described.

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