Lithopedion

Case contributed by Laughlin Dawes
Diagnosis certain

Presentation

Incidentally discovered calcified pelvic mass during workup for low back pain.

Patient Data

Age: 75 years
Gender: Female

Note: This case has been tagged as "legacy" as it no longer meets image preparation and/or other case publication guidelines.

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Extra-uterine calcified fetal skeleton on MPCR (multi-planar curved reformat) images.

Source of image: Chang CM, Yu KJ, Lin JJ, Sheu MH, Chang CY. Lithopedion case report. Chinese Medical Journal (Taipei) 2001;64(6):369-372. PMID: 11534806

Case Discussion

The patient recalled abnormal obstetric history 50 years ago. Otherwise, there was no relevant clinical or lab abnormality.

A lithopedion (litho = stone; paedion = child), or stone baby, is a rare phenomenon which occurs most commonly when a fetus dies during an ectopic pregnancy. If the dead fetus is too large to be reabsorbed by the mother’s body it becomes a foreign body to the mother’s immune system. To protect itself from possible infection, the mother’s body will encase the fetus in a calciferous substance. The fetus is gradually mummified becoming a stone baby. Lithopedions may occur from 14 weeks gestation to full term. It is not unusual for a stone baby to remain undiagnosed for decades and found incidentally when taking plain films for various reasons (like this case).

Credit: Dr Ahmed Haroun.

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