Fetus in fetu (or foetus in foetu) is a rare developmental abnormality in which a mass of tissue resembling a fetus forms inside the body of its twin. An early example of the phenomenon was described in 1808 by George William Young.[1]
Anteroposterior abdominal radiograph shows a soft-tissue mass in the right hemiabdomen. The mass contains calcified osseous-appearing structures of varying sizes and shapes.The postoperative specimen from the previous image shows a fairly well developed fetus lying on its back, with rudimentary digits.A computed tomography scan of the same patient's abdomen pre-operation reveals a large retroperitoneal soft-tissue mass. There are long hyperdense opacities that resemble fetal bones.
There are two hypotheses for the origin of a "fetus in fetu". One hypothesis is that the mass begins as a normal fetus but becomes enveloped inside its twin.[2] The other hypothesis is that the mass is a highly developed teratoma. "Fetus in fetu" is estimated to occur in 1 in 500,000 live births.[3]
A fetus in fetu can be considered alive, but only in the sense that its component tissues have not yet died or been eliminated. Thus, the life of a fetus in fetu is akin to that of a tumor in that its cells remain viable by way of normal metabolic activity. However, without the gestational conditions in utero with the amnion and placenta, a fetus in fetu can develop into, at best, an especially well differentiated teratoma; or, at worst, a high-grade metastaticteratocarcinoma. In terms of physical maturation, its organs have a working blood supply from the host, but all cases of fetus in fetu present critical defects, such as no functional brain, heart, lungs, gastrointestinal tract, or urinary tract. Accordingly, while a fetus in fetu can share select morphological features with a normal fetus, it has no prospect of any life outside of the host twin. Moreover, it poses clear threats to the life of the host twin on whom its own life depends.[4]
Hypotheses of development
There are two main hypotheses about the development of fetus in fetu.
Fetus in fetu may be a parasitic twinfetus growing within its hosttwin. Very early in a monozygotic twin pregnancy, in which both fetuses share a common placenta, one fetus wraps around and envelops the other. The enveloped twin becomes a parasite, in that its survival depends on the survival of the host twin, by drawing on the host twin's blood supply. The parasitic twin is anencephalic (without a brain) and lacks some internal organs, and as such is unable to survive on its own. As the host twin has to "feed" the enveloped twin from the nutrients received over a single umbilical cord, they usually die before birth.[citation needed]
References
^Young GW (1808). "Case of a Fœtus found in the Abdomen of a Boy". Medico-Chirurgical Transactions. 1: 236–264. PMC2128792. PMID 20895115.
^Chua JH, Chui CH, Sai Prasad TR, et al. (2005). (PDF). Annals of the Academy of Medicine Singapore. 34: 646–9. Archived from the original (PDF) on 2007-10-11.
^Grant P, Pearn JH (May 1969). "Foetus-in-foetu". The Medical Journal of Australia. 1 (20): 1016–1019. doi:10.5694/j.1326-5377.1969.tb49866.x. PMID 5815070. S2CID 209072187. — source not consulted; cited here following Hoeffel CC, Nguyen KQ, Phan HT, Truong NH, Nguyen TS, Tran TT, Fornes P (June 2000). "Fetus in fetu: a case report and literature review". Pediatrics. 105 (6): 1335–1344. doi:10.1542/peds.105.6.1335. PMID 10835078.
^Khalifa NM, Maximous DW, Abd-Elsayed AA (January 2008). "Fetus in fetu: a case report". Journal of Medical Case Reports. Jmedicalcasereports.com. 2 (1): 2. doi:10.1186/1752-1947-2-2. PMC2253549. PMID 18186928.
^Basu A, Jagdish S, Iyengar KR, Basu D (October 2006). "Fetus in fetu or differentiated teratomas?". Indian Journal of Pathology & Microbiology. 49 (4): 563–565. PMID 17183856.
External links
Look up fetus in fetu in Wiktionary, the free dictionary.
Wikimedia Commons has media related to Fetus in fetu.
Xray of fetus in fetu
August 20, 2023
fetus, fetu, foetus, foetu, rare, developmental, abnormality, which, mass, tissue, resembling, fetus, forms, inside, body, twin, early, example, phenomenon, described, 1808, george, william, young, anteroposterior, abdominal, radiograph, shows, soft, tissue, m. Fetus in fetu or foetus in foetu is a rare developmental abnormality in which a mass of tissue resembling a fetus forms inside the body of its twin An early example of the phenomenon was described in 1808 by George William Young 1 Anteroposterior abdominal radiograph shows a soft tissue mass in the right hemiabdomen The mass contains calcified osseous appearing structures of varying sizes and shapes The postoperative specimen from the previous image shows a fairly well developed fetus lying on its back with rudimentary digits A computed tomography scan of the same patient s abdomen pre operation reveals a large retroperitoneal soft tissue mass There are long hyperdense opacities that resemble fetal bones There are two hypotheses for the origin of a fetus in fetu One hypothesis is that the mass begins as a normal fetus but becomes enveloped inside its twin 2 The other hypothesis is that the mass is a highly developed teratoma Fetus in fetu is estimated to occur in 1 in 500 000 live births 3 Contents 1 Classification as life 2 Hypotheses of development 2 1 Teratoma hypothesis 2 2 Parasitic twin hypothesis 3 References 4 External linksClassification as life EditA fetus in fetu can be considered alive but only in the sense that its component tissues have not yet died or been eliminated Thus the life of a fetus in fetu is akin to that of a tumor in that its cells remain viable by way of normal metabolic activity However without the gestational conditions in utero with the amnion and placenta a fetus in fetu can develop into at best an especially well differentiated teratoma or at worst a high grade metastatic teratocarcinoma In terms of physical maturation its organs have a working blood supply from the host but all cases of fetus in fetu present critical defects such as no functional brain heart lungs gastrointestinal tract or urinary tract Accordingly while a fetus in fetu can share select morphological features with a normal fetus it has no prospect of any life outside of the host twin Moreover it poses clear threats to the life of the host twin on whom its own life depends 4 Hypotheses of development EditThere are two main hypotheses about the development of fetus in fetu Teratoma hypothesis Edit Main article Teratoma Fetus in fetu may be a very highly differentiated form of dermoid cyst itself a highly differentiated form of mature teratoma 5 Parasitic twin hypothesis Edit Main article Parasitic twin Fetus in fetu may be a parasitic twin fetus growing within its host twin Very early in a monozygotic twin pregnancy in which both fetuses share a common placenta one fetus wraps around and envelops the other The enveloped twin becomes a parasite in that its survival depends on the survival of the host twin by drawing on the host twin s blood supply The parasitic twin is anencephalic without a brain and lacks some internal organs and as such is unable to survive on its own As the host twin has to feed the enveloped twin from the nutrients received over a single umbilical cord they usually die before birth citation needed References Edit Young GW 1808 Case of a Fœtus found in the Abdomen of a Boy Medico Chirurgical Transactions 1 236 264 PMC 2128792 PMID 20895115 Chua JH Chui CH Sai Prasad TR et al 2005 Fetus in fetu in the pelvis PDF Annals of the Academy of Medicine Singapore 34 646 9 Archived from the original PDF on 2007 10 11 Grant P Pearn JH May 1969 Foetus in foetu The Medical Journal of Australia 1 20 1016 1019 doi 10 5694 j 1326 5377 1969 tb49866 x PMID 5815070 S2CID 209072187 source not consulted cited here following Hoeffel CC Nguyen KQ Phan HT Truong NH Nguyen TS Tran TT Fornes P June 2000 Fetus in fetu a case report and literature review Pediatrics 105 6 1335 1344 doi 10 1542 peds 105 6 1335 PMID 10835078 Khalifa NM Maximous DW Abd Elsayed AA January 2008 Fetus in fetu a case report Journal of Medical Case Reports Jmedicalcasereports com 2 1 2 doi 10 1186 1752 1947 2 2 PMC 2253549 PMID 18186928 Basu A Jagdish S Iyengar KR Basu D October 2006 Fetus in fetu or differentiated teratomas Indian Journal of Pathology amp Microbiology 49 4 563 565 PMID 17183856 External links Edit Look up fetus in fetu in Wiktionary the free dictionary Wikimedia Commons has media related to Fetus in fetu Xray of fetus in fetu Retrieved from https en wikipedia org w index php title Fetus in fetu amp oldid 1161665932, wikipedia, wiki, book, books, library,
