Re: What is the process that creates a stone baby?

At first I thought that the site that you steered me to was a hoax. I am still not sure that the pictures at:[Moderator's Warning: The following site contains graphic pictures that may not be suitable for children and the sqeamish - ADULT SUPERVISION ADVISED]

http:// www.obgyn.net/ENGLISH/PUBS/ARTICLES/Stone_Baby.htm

are legitimate, but the site in general seems credible.

I searched for articles using MEDLINE:

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed

If you enter the word 'lithopedion' you will find a number of clinical case reports of 'stone babies'. There have been about 300 reports in the medical literature. In some cases, the woman has carried the stone baby for 50 years. The earliest case I found was discovered in an archeology dig in the Southwest. You would expect the stone baby to preserve well! The citation is:

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Am J Obstet Gynecol 1993 Jul;169(1):140-1

Three-millennium antiquity of the lithokelyphos variety of lithopedion. Rothschild BM, Rothschild C, Bement LC.

Arthritis Center of Northeast Ohio, Northeastern Ohio University College of Medicine, Youngstown 44512. Identification of a 3100-year-old lithopedion in the Archaic Southwest antedates its first clinical notation by 2100 years. It was only the "autopsy" of time (excavation of the site) that allowed its presence to be brought to light.

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Another picture may be found at:
http://www.taiwanheadlines.gov.tw/20000106/20000106s5.html

Here is the case report:

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Zhonghua Yi Xue Za Zhi (Taipei) 2001 Jun;64(6):369-72

Lithopedion.

Chang CM, Yu KJ, Lin JJ, Sheu MH, Chang CY. Department of Obstetrics and Gynecology, Taipei Veterans General Hospital, Taiwan, ROC.

Lithopedion is a rare obstetrical outcome of an undiagnosed and untreated advanced abdominal pregnancy, mostly found incidentally. We present a case of lithopedion. In a 76 year-old female suffering from cervical neoplasm, total abdominal hysterectomy was performed for the lesion and the lithopedion was found incidentally. The patient's history was unremarkable, and laboratory tests were normal. The patient recalled having experienced a severe abdominal pain about 50 years before. Her physician had felt "a benign tumor" in her pelvis at that time, indicating that the stone child had retained in the maternal peritoneal cavity for 50 years.

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Now let's deal with the biology. These cases seem to arise from rare abdominal pregnancies in which the fetus is too large to be resorbed by the body. The calcification occurs subcutaneously (under the skin) of the fetus, which typically becomes wrapped in adhesions (scar tissue).

This doesn't happen to tumors, because they are viable cells that are not recognized as foreign by the immune system. It doesn't happen to a bullet, because it is not possible to calcify a solid piece of lead. The biological advantage of this process in general (not fetuses specifically) is that it makes sense to have some way of dealing with foreign objects in the body. Small masses of dead cells can be invaded and consumed by macrophages (a kind of white blood cell). For larger masses, this is more difficult.

The cases of lithopedions seem to involve a developmental arrest of the fetus. The immune system must eventually recognize the fetus as foreign.

The process is not exactly what happens when an oyster makes a pearl. If it were, then a bullet (to use your example) could become wrapped in "stone" in the body. It is more like what happens to the plaque on your teeth, which calcifies and is removed by a dental cleaning.

Thank you for a very interesting question. I had never heard of this!

Yours,

Paul Szauter
Mouse Genome Informatics