Abstract
Craniopharyngiomas (CPs) are rare epithelial tumors located mainly in the sellar/parasellar region. CPs have been classified into histopathologically, genetically, clinically and prognostically two distinctive subtypes: adamantinomatous and papillary variants.
Aim: To determine the immunohistochemical expression of beta-catenin, EGFR, ErbB2, and p63 in adamantinomatous and papillary CPs. Materials and methods: beta-Catenin, EGFR, ErbB2, and p63 immunostaining was performed on paraffin embedded tissue sections of 25 CPs including 18 adamantinomatous craniopharyngioma (ACP) and 7 cases of papillary craniopharyngiomas (PCPs).
Results: 17 cases (94%) of ACP exhibited strong nuclear/cytoplasmic expression of beta-catenin. On the contrary, all cases of PCP showed exclusively membranous expression (P value < 0.0001). Regarding EGFR, 15 (83%) and 5 cases (71%) of APC and PCP respectively were positive. On the other hand, only 3 cases (17%) of APC and none of PCP exhibited positivity for ErbB2. p63 over-expression was observed in 16 cases of ACP (89%) and 6 cases of PCP (86%). However, the distribution of p63 staining was diffuse in ACP, while in PCP; the staining was mainly restricted to the basal cell layer.
Conclusion: Nuclear accumulation of beta-catenin is a diagnostic hallmark of the ACP and is very helpful in the differential diagnosis between both ACP and PCP in the setting of small biopsies. Moreover, the restricted nuclear beta-catenin accumulation in the cohesive cell clusters within the whorl-like areas supports that aberrant beta-catenin expression may play a role in the morphogenesis of ACP. (C) 2015 The Authors. Production and hosting by Elsevier B.V. on behalf of National Cancer Institute, Cairo University.