title: Fetus in fetu--diagnostic criteria and differential diagnosis--a case report and literature review.
abstract: Fetus-in-fetu (FIF) is a rare congenital condition in which a vertebrate fetus is incorporated within its twin. The authors report the case of a newborn boy with prenatal ultrasonographic diagnosis of intraabdominal mass, provoking compression of the left kidney. Plain abdominal radiography, ultrasonography, and computer tomography showed a cystic mass containing multiple calcifications. Pathologic examination showed an irregular fetiforme mass, weighing 8 g, attached to an amniotic sac by a rudimentary umbilical cord with 2 rudimentary limbs, vertebral bodies, encephalus, coroidal plexus, stomach, duodenum, bowel, adrenal glands, upper and lower respiratory tissue, spleen, lymphoid tissue, single cavity heart, and kidney. Molecular analysis using an informative genetic marker, for uniparental isodisomy of chromosomes 14 and 15 showed no genetic difference between the host infant and the fetiform mass. Serum alpha-fetoprotein was < or = 16.000 UI/mL (reference values for age, 4 to 18.9904 UI/mL) before surgery and 8.364 UI/mL after surgery.
authors.affiliation: Department of Neonatology, Service de Pediatric/UCEP, Hospital S. Francisco Xavier, Lisbon, Portugal.
authors.forename: Ariane
authors.initials: A
authors.lastname: Brand
authors.forename: Maria Cecilia
authors.initials: MC
authors.lastname: Alves
authors.forename: Carla
authors.initials: C
authors.lastname: Saraiva
authors.forename: Pedro
authors.initials: P
authors.lastname: Loío
authors.forename: João
authors.initials: J
authors.lastname: Goulão
authors.forename: João
authors.initials: J
authors.lastname: Malta
authors.forename: J Martins
authors.initials: JM
authors.lastname: Palminha
authors.forename: Mena
authors.initials: M
authors.lastname: Martins
mesh_terms: D000005:Abdomen; D000328:Adult; D002114:Calcinosis / Q000209:etiology; D003560:Cysts / Q000175:diagnosis; D003937:Diagnosis, Differential; D004476:Ectodermal Dysplasia / Q000209:etiology; D005260:Female; D005313:Fetal Death; D005333:Fetus / Q000002:abnormalities* / Q000473:pathology; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D011296:Prenatal Diagnosis; D013724:Teratoma / Q000175:diagnosis; D014430:Twins, Monozygotic