Fetus in fetu computed tomographic findingsA.A.BahnassyRadiology department,Prince Sultan Military Medical city,Riyadh,Saudi Arabia.A A Bahnassy ,MSc,FRCRCorresponding author:A Bahnassy (email@example.com)Fetus in fetu is a rare developmental aberration, characterized by encasement of partiallydeveloped monozygotic, diamniotic, and monochorionic fetus into the normally developinghost. Mustafa G, Mirza B, Iqbal S, Sheikh A. A case of fetus in fetu. APSP J Case Rep 2012;3: 9. A newborn was refered to radiology department Prince Sultan Military Medical City fora large palpable abdominal mass.Computed Tomography revealed a well encapsulated mass .The mass shows fluid ,soft tissue ,fatty and bony elements (fig 1) , showingdifferentiation into cortex and marrow.Structures femur and pelvis like are seen.(fig 2 )
Fig 1:fatty ,soft tissue ,bony and cystic elements.Fig 2 :femur and pelvic bone like structures.Discussion:The exact embryogenesis of fetus in fetu is controversial. Some investigators proposethat fetus in fetu occurs from the anomalous embryogenesis in a diamnioticmonochorionic twin pregnancy in which a malformed monozygotic twin lies within thebody of its fellow twin . Others consider it to represent a highly organized teratoma. (1)This condition has a 2:1 male predominance, with most patients presenting with anabdominal mass in the 1st year of life. Other reported locations include the cranial cavity
and the scrotum .The number of fetuses in fetu is usually single; however, multiplefetuses in fetu have been reported (2,3)Imaging played an important role in our ability to correctly diagnose both cases in aprospective fashion. The diagnosis of fetus in fetu can be made with abdominalconventional radiographs, by identifying a vertebral column and/or specific bonystructures (4). Nocera et al initially described the CT appearance of fetus in fetu. TheCT findings were those of a mass that consisted of a round or tubular collection of fatthat surrounded a central bony structure. The identification of vertebrae or long bones isessential for establishing this diagnosis prospectively (5).References:1.Luzzatto C, Talenti E, Tregnaghi A, Fabris S, Scapinello A, Guglielmi M. Double fetusin fetu: diagnostic imaging. Pediatr Radiol 1994;24:602-603.Medline2.Yang ST, Leow SW. Intracranial fetus in fetu: CT diagnosis. AJNR Am J Neuroradiol1992; 13:1326-1329.3.Heifetz SA, Alrabeeah A, Brown BS, Lau H. Fetus in fetu: a fetiform teratoma. PediatrPathol 1988; 8:215-226.Medline4.Knox JS, Webb AJ. The clinical features and treatment of fetus in fetu: two casereports and review of literature. J Pediatr Surg 1975;10:483-489.Medline5.Nocera RM, Davis M, Hayden CK, Jr, Schwartz M, Swischuk LE. Fetus in fetu. AJRAm J Roentgenol 1982; 138:762-764.