Desmoplastic Medulloblastoma

Desmoplastic medulloblastoma is a variety of the typical cerebellar tumor, characterized by distinctive clinical and morphological features. It usually occurs in adults, is localized in a lateral lobe and shows expansive rather than infiltrative patterns of growth with early leptomeningeal involvement. The most remarkable histological feature is an extremely rich network of reticulin fibres, among which the typical cells of medulloblastoma are found. Another interesting although incostant feature is the presence of well circumscribed reticulin-free « pale » or « glomerular » areas. The histogenesis of this variety of medulloblastoma is discussed in the light of the most recent studies, and Rubinstein and Northfield's proposal of identifying the so-called «circumscribed arachnoidal cerebellar sarcoma » with this tumor is accepted.