Cytomorphology of anaplastic ependymoma in a pleural effusion. A case report.

In a 42-year-old women a recurrent anaplastic ependymoma of the frontal lobe developed intracerebral metastases and, after implantation of an atrioventricular shunt, also metastasized to the lung, pleural cavity and mediastinal lymph nodes. In routinely stained smear preparations of the pleural effusion sediment, the typical cytologic features of an anaplastic ependymoma were found--papilliform cell clusters with acellular axes ("pseudorosettes"), incomplete true ependymal rosettes, and epithelioid and tanycytoid tumor cells with signs of anaplasia. A peculiar matrix material was a characteristic feature of this case and, to our knowledge, was not reported previously. It consisted of refringent, fibrillar strands composed of tightly packed, roundish to rodshaped granules. This matrix seemed to be associated with the cytoplasmic processes of the tumor cells.