Craniopharyngiomas commonly exhibit which histologic feature, reflecting their origin from Rathke pouch?

• A. Spindle cell sarcoma
• B. Neural tissue with myelin
• C. Melanin pigment
• D. Keratin pearls

Answer: (D)

Craniopharyngiomas come from Rathke pouch, an ectodermal outgrowth that forms the anterior pituitary. Because of this origin, the tumor often shows squamous epithelial differentiation with keratin production. The classic histologic feature is keratin pearls—concentric, layered keratin within tumor nests—reflecting this squamous differentiation. This is especially characteristic of the adamantinomatous type, which can also show palisading basal cells and a stellate reticulum, but the keratinized pearls are the hallmark.

Other options don’t fit the origin or typical histology: spindle cell sarcoma would be mesenchymal, neural tissue with myelin points to CNS glial elements, and melanin pigment indicates a melanocytic lesion. Keratin pearls specifically embody the squamous, ectodermal lineage associated with Rathke pouch remnants.