Differential expression of immunohistochemistry markers for epithelial/squamous cells in adamantinomatous craniopharyngioma

Craniopharyngioma are histologically a benign neoplasm that occurs in the sellar and suprasellar region, with an infiltrative growth pattern, accounts for 1.2-4.6% of all intracranial tumors.1 They are the most common non-neuroepithelial intracerebral neoplasm in children accounting for 5-10% of intracranial tumors in this age group. A bimodal age distribution of ACP is observed, with peaks in children aged 5-15years and adults 45-60years.1 They are often difficult to excise surgically, and they have a 10% to 40% recurrence rate.2 There are at two types of craniopharyngioma: Adamantinomatous craniopharyngioma (ACP) and papillary craniopharyngioma (PCP). Both have distinct morphology and different clinical behavior. ACP has at least four different squamous histological areas: superficial mature squamous (SMS), loosely cohesive aggregates of squamous cells known as “stellate reticulum” (SR), palisaded basal columnar (PBC) cells and nodules of wet keratin (WK) (Figure 1, Figure 2 & Figure 3). Cystic cavities containing squamous debris are lined by flattened epithelium. PCP occurs virtually exclusively in adults with mean age of 40-50years.3,4 Histologically, it is different from ACP by lacking nuclear palisading, wet keratin, and dystrophic calcification.5