The big-spending club did not disclose the details of the deal, but local reports indicated that the player joined on a one-season loan with an option to make the move permanent.
The 21-year-old centre-back, who began his football career through the youth ranks of Egyptian side Ismaily, joined Rostov in 2024 from the coastal club.
El-Askalany made 10 appearances for Rostov before suffering a lengthy spell on the sidelines due to a cruciate ligament tear. He recently recovered from the injury and is available to play again.
The defender has previously represented Egypt at both youth and Olympic levels.
His arrival is part of Pyramids' strategic plan to mount a strong challenge for all titles next season, including the CAF Champions League, under newly appointed South African manager Rulani Mokwena.
Pyramids finished the previous domestic campaign in second place in the Egyptian Premier League, just two points behind champions Zamalek.
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