Gemistocytic astrocytomas: a reappraisal

Abstract

Although gemistocytic astrocytomas are considered slow-growing astrocytomas, they often behave aggressively. To clarify the biological and clinical behavior of these rare tumors, the authors retrospectively identified 59 patients with gemistocytic astrocytoma whose tumors were diagnosed and treated between June, 1976, and July, 1989. Three patients who were lost to follow-up review were excluded, as were two whose original slides could not be obtained and three whose tumors were diagnosed at recurrence or at autopsy. The pathological material of the remaining 51 patients was reviewed using two sets of histological criteria. Thirteen patients (Group A) had "pure" gemistocytic astrocytoma, defined as a glial tumor with more than 60% gemistocytes/high-power field and a background of fibrillary astrocytes. Fifteen patients (Group B) had "mixed" gemistocytic astrocytoma, defined as a glial tumor with 20% to 60% gemistocytes/high-power field and a background of anaplastic astrocytes. Twenty-three tumors did not meet these criteria and were excluded from analysis. The median age of the patients was 48.5 years in Group A and 38.3 years in Group B (p less than 0.05). In both groups, the median Karnofsky Performance Scale score was greater than 90%. All patients underwent surgical procedures (four total and 19 partial resections, and five biopsies) and postoperative radiation therapy. The majority also had interstitial brachytherapy, chemotherapy, or both. Ten patients had one reoperation for tumor recurrence and one had two reoperations; other treatments for recurrence included brachytherapy, chemotherapy, and repeat irradiation. All four patients who originally underwent gross total resection are still alive; all five who had a biopsy have died. There was no significant difference in median survival times between groups: 136.5 weeks in Group A (range 10 to 310+ weeks) and 135.6 weeks in Group B (range 31 to 460+ weeks). Analysis of all 28 patients showed a better prognosis for patients less than 50 years of age (185 vs. 36 weeks survival time; p less than 0.001), patients with preoperative symptoms lasting for more than 6 months (228.1 vs. 110.2 weeks survival time; p less than 0.05), and patients with seizures as the first symptom (185.7 vs. 80 weeks survival time; p less than 0.01). Survival time did not correlate with the presence of perivascular lymphocytic infiltration. The authors conclude that the presence of at least 20% gemistocytes in a glial neoplasm is a poor prognostic sign, irrespective of the pathological background. It is proposed that gemistocytic astrocytomas be classified with anaplastic astrocytomas and treated accordingly.

Low-grade astrocytomas: the prognostic value of fibrillary, gemistocytic, and protoplasmic tumor histology

“…This variant has been shown to be more prone to malignant transformation and is associated with a shorter overall survival. 12,17,21,31,35 A study by Krouwer et al…”

“…These tumors have been thought to have significantly lower survival compared with those with little or no gemistocytes. 17 Protoplasmic astrocytomas are the rarest histological subtype and are composed of neoplastic astrocytes with small cell bodies, few processes, and little GFAP expression. These tumors have been suggested to have a similar prognosis to fibrillary astrocytomas, although the literature consists of case reports and small series.…”

Interstitial 125I radiosurgery of supratentorial de novo WHO Grade 2 astrocytoma and oligoastrocytoma in adults

“…Gemistocytic astrocytomas are associated with more malignant behavior and should be analyzed separately as demonstrated elsewhere. 4,10 Thus, 306 adults (aged Ն 18 yrs) had supratentorial tumors that were classified as WHO Grade 2 astrocytoma or oligoastrocytoma. 11,12 It was assumed that these 2 tumor entities did not differ significantly in terms of prognosis and length of survival after implant therapy.…”

Proliferation and aneusomy predict survival of young patients with astrocytoma grade II

“…with high percentages (460%) of gemistocytes, in fact, behave in a more similar manner to A III (Krouwer et al, 1991). Although two of our gemistocytic samples contained lower percentages of gemistocytes, the increased proliferation activity and the presence of aneusomy in all three samples was associated with a relatively short survival (range 41 -43 months).…”