Lectin histochemistry of human meningiomas.

The lectins Peanut agglutinin (PNA), Canavalia ensiformis (Con A), Ulex europaeus-1 (UEA-1), Dolichos biflorus (DBA), Triticum vulgaris (WGA) were studied in a series of 36 meningiomas (16 meningotheliomatous-including 3 recurrences, 7 transitional, 4 angiomatous, 2 "hemangiopericytic", 3 papillary-including 1 recurrence, 4 anaplastic-including 3 recurrences. PNA binds to all cases of meningotheliomatous, transitional, papillary and anaplastic meningiomas (including recurrent cases) but the staining is more intense in tumor cells of anaplastic and papillary type. A semiquantitative study showed differences of PNA-reactivity in the different subtypes of meningiomas. In meningotheliomatous meningiomas PNA-positivity was encountered in numerous neoplastic cells (50%), whereas papillary and anaplastic subtypes expressed strong cytoplasmic staining of few tumor cells (< 5%). Con A shows the same pattern of reactivity described for PNA, but more weakly. Our results suggest that PNA is a marker of differentiation in meningiomas rather than malignant transformation and can have prognostic relevance.