CYSTIC NEUROBLASTOMA - EMPHASIS ON GENE-EXPRESSION, MORPHOLOGY, AND PATHOGENESIS

Cystic neuroblastoma (CN) is an unusual variant of neuroblastoma chara cterized by a grossly visible cyst(s) and almost always distinctive mi crocysts on light microscopy. Rarely, CN will appear solid grossly, bu t microcysti fication will be present. We examined the clinical, patho logic, and biologic features of 17 cases of CN. The majority of CN had been detected by prenatal ultra sound. The tumors were favorable stag e, stroma-poor, but with low or intermediate mitotic-karyorhectic indi ces and had favorable biologic markers reflected by aneuploidy and by an absence of N-myc amplification and chromosome Ip deletions. However , the high trk expression typically identified in good risk tumors was absent. Although the complete natural history of CN is not fully defi ned, our experience suggests that some tumors progress in size, wherea s others may spontaneously regress or mature. The clinical outcome is excellent, as is expected in localized and stage 4S neuroblastoma in i nfancy.