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Spontaneous retrograde urolithiasis migration in a woman: a case report and possible mechanism

Urolithiasis is a condition which is commonly encountered in practice, however retrograde migration of a calculus within the ureter has only recently been documented with few cases reported in the literature. We present the case of a 47-year-old woman presenting with symptomatic urolithiasis confirmed by CT who recovered from her symptoms only for it to be discovered that the calculus had undergone retrograde migration into the renal calyx on a follow up CT examination. We theorise that retrograde urolithiasis migration may be an innate safety mechanism that evolved to prevent complications and/or death from urolithiasis impaction by attempting to return a migrated lithiasis to the renal calyx.