lithopedion

A fetus large enough to avoid expulsion or absorption takes a long time to accumulate enough calcium deposits that it turns to stone. Lithopedia have been extracted from women as old as 94, who have been unknowingly carrying the fetuses for upwards of 60 years. Serious complications like intestinal obstruction can result from lithopedion formation, but many cases are stable for a very long time, sometimes going unnoticed for decades. Often the lithopedion is initially misdiagnosed as a cyst or tumor, and is only shown to be a calcified fetus upon removal.

The physician Albucasis was the first to document the lithopedion phenomenon, in his 11th century treatise on surgery. In 1557, physician Israel Spach included in his gynecological text an illustration of a lithopedion in situ (that is, inside a woman's opened womb). He appended this caption: "Deucalion cast stones behind him and thus fashioned our tender race from the hard marble. How comes it that nowadays, by a reversal of things, the tender body of a little babe has limbs nearer akin to stone?" Spach apparently considered the lithopedion to represent a reversion to (mythical) early forms of humanity, in something like the way that Ernst Haeckel would later see the early evolution of man reflected in the fish-like fetus.

Lithopedia are less common in developed countries with adequate health care, since pregnancies that are neither carried to term nor obviously terminated are not likely to go unnoticed.

A stone baby, or lithopedion, results when a fetus dies during an ectopic (typically abdominal) pregnancy, is too large to be reabsorbed by the body, and calcifies. It is not unusual for a lithopedion to remain undiagnosed for decades, and it is often not until a patient is examined for other conditions that a stone baby is found. The oldest reported case is that of a 94 year old woman, whose lithopedion had probably been present for over 60 years.

Lithopedion is a rare phenomenon, occurring once in about 20 000 pregnancies, and with less than three hundred cases noted in medical literature accumulated over some 400 years. Lithopedion may occur from 14 weeks' gestation to full term. The earliest stone baby is one found in an archaeological excavation, dated to 1100 BCE.

A related condition is known as fetus papyraceus, in which the fetus is one of two or more sharing the womb. If the fetus is older than eight weeks at the time of its death, and is retained in the uterus for at least ten weeks, it may undergo mechanical compression such that it takes on a flattened, mummified appearance and resembles parchment paper.

Further reading

CAUTION: GRAPHIC IMAGES

OBGYN Net =>http://www.obgyn.net/ENGLISH/PUBS/ARTICLES/Stone_Baby.htm
PubMed (enter 'lithopedion' in search box) => http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=Search&DB=PubMed

This writeup has also appeared in WikipediaŽ http://en.wikipedia.org