Contributed by Emily F. Gorman, MD1; Asim K. Bag, MD2; Cheryl Ann Palmer, MD1, 3
1Department of Pathology, 2Department of Radiology, 3Department of Neurology, University of Alabama at Birmingham
CLINICAL HISTORY AND IMAGING STUDIES
A 48-year-old man with a history of hypertension, peripheral vascular disease and a 50-pack-year history of smoking, presented with new onset vertigo, tinnitus, diplopia and ataxia in January of 1978. There was no family history of any brain lesions, neurological symptoms or other contributory diseases. CT scan showed a radiolucent defect in the left cerebellar hemisphere with a possible mural nodule. In ensuing months, worsening symptoms were experienced with a corresponding increase in lesion size on re-imaging. Four months later, a left posterior fossa craniotomy was performed and revealed a single cystic lesion containing copious amounts of straw- colored fluid and a single mural nodule in the inferior portion of the cyst. Following resection, he was followed clinically until 1985 at which time follow-up was discontinued. He did well until January of 1993 when he presented with progressively worsening episodic headaches and retro-orbital pressure. In the following months, additional symptoms including slurred speech, left facial droop; upper and lower extremity weakness were documented. Subsequent MRIs of the brain (02/93, 03/93) showed diffuse nodular leptomeningeal enhancement in the posterior fossa. Multiple low intensity lesions coated the cerebellum, and similar lesions were located anterior to the pons, in the suprasellar cistern, at the tip of the temporal lobe, in the right Meckel's cave, and in the third ventricle (Figures 1, 2 and 3). In addition, an MRI of the spine (03/93) showed multiple extra-axial intradural enhancing nodules throughout the length of the thoracic cord, consistent with drop metastases. He was admitted for radiotherapy, receiving 2600 rads in 10 fractions over a 19- day period in March 1993. During this hospitalization, his hematocrit ranged from 53 to 61%, demonstrating polycythemia. Despite therapy, his condition progressively declined, and he succumbed. The family authorized consent for examination of the brain only at autopsy.
Gross examination during the brain-only autopsy revealed a well-demarcated hyperemic cerebellar lesion and numerous leptomeningeal lesions (Figure 4). Additionally, numerous small leptomeningeal tumor nodules were noted at the base of the brain over both frontal and temporal lobes ranging in size from 4-9 mm. A 2 x1 cm tumor mass in the midbrain and pons was present that extended to and involved the foramen magnum. Small tumor nodules surrounded the right optic nerve as well as the pituitary fossa. Several tumor nodules were also identified at the base of the skull.
Histopathological examination revealed a capillary - rich neoplasm containing interstitial stromal cells with abundant lacy, eosinophilic cytoplasm. The nuclei showed modest pleomorphism with vesicular chromatin and occasional prominent nucleoli (Figures 5, 6 and 7). No mitoses were found. The MIB-1 (Ki67) labeling index was positive in less than 1% of the tumor nuclei (Figure 8). The histology of the metastatic nodules was identical to the tumor removed 15 years prior from the cerebellum. There was no histological evidence of anaplasia in the recurrent tumor, however there was evidence of superficial invasion of brain parenchyma (Figures 9 and 10).