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How do fluke parasites renew their outer integument inside a host?

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A pangolin walks through grass with a blue circle around it and the word endangered written in white across the image. — Integument The pangolin is the only mammal in the world covered in scales.

Fluke parasites renew their outer integument through the continuous release of secretory bodies contained within the outer part of the tissue. These bodies are released at the surface to renew the apical membrane, a process that serves as a protective mechanism against the host's immune response.1

Unlike free-living flatworms, which possess an epidermis of ciliated cells, the tegument of flukes is a metabolically active syncytium—a layer of cells not separated by cell walls. This specialized structure, which often features spines and sensory papillae, allows the parasite to maintain its integrity while residing within the challenging environment of a host.21