Oh, and it’s a good one, too. (By good I mean super gross.) Teratomas, for those of you not as repulsed/fascinated by them as I am, are benign tumors in which germ cells gone awry grow random body parts like teeth, hair, bone and soft tissue like muscle, thyroid and skin. They usually set up shop in ovaries or, more rarely, testicles because that’s where germ cells are supposed to be going about the business of making sperm and eggs during embryonic development, and often go undetected for their host’s entire life. While not uncommon, teratomas make the news because of how creepy they are — they’re not absorbed “evil” twins, no matter what the headlines might say — and how infrequently they’re found.

Teratomas are even rarer in the archaeological record. An encapsulated calcified teratoma was found in the remains of late Roman-era woman from the early 5th century unearthed from a necropolis in La Fogonussa, Spain, in 2010. Before that specimen was published, only one other example was known, found inside the skeleton of a Roman woman unearthed in 1999-2000 from a slave necropolis attached to an aristocratic villa just outside of Rome (pdf of the paper in French here). Now we can add a third to this very elite list: an ovarian teratoma discovered inside the abdominal cavity of a girl unearthed from the Colonial-era cemetery in Eten, Lambayeque Region, on the northwest coast of Peru.

Archaeologists from the Lambayeque Valley Biohistory Project (LVBP), a multidisciplinary international program founded in 2003 that studies skeletal remains on the desert north coast of Peru for what they reveal about the 10,000-year history of human settlement in the area, excavated the ruins of Eten between 2009 and 2011. The skeleton of the young woman was found in the cemetery of the Chapel of the Divino Niño Serranito de Eten, one of 500 Colonial Period burials in the chapel cemetery. Eten had been a small fishing village before the Spanish came. It was expanded into a colonial settlement called a reducción in the 1560s. Reducciónes were forced labour/Christianization resettlement towns, designed to break the cultural structure of small kin-based, self-sustaining villages scattered in the area, corral the work force in larger urbs for more efficient exploitation in the Andean silver mines and two-birds-with-a-stone conversion to Christianity. Eventually reducciónes spread throughout Spanish holdings in Central and South America, but they began in Peru, the brainchild of 5th viceroy Francisco de Toledo.

The young woman, labelled burial CNS U2-60, was one of the earliest to die in Eten after resettlement. It’s not clear what killed her, but her teratoma is so extreme that it might have been a factor. The Spain teratoma had four small, malformed teeth and bone formation inside the calcified capsule. The one found in Rome had five malformed teeth inside a fragmented spherical bony structure. The Andean teratoma has 83 pieces of bone and 37 malformed baby teeth. And that’s all that’s left now. Who knows what kind of random organ bits were in there before decomposition. It was such a large assortment of bones and teeth that at first researchers thought it might be a sacrificed animal, but its location in the abdominal cavity meant that it had to have been inside of her at the time of death, and besides, none of those bones and teeth looked like regular bones and teeth of any kind of animal.

Looking closely at the dozens of extra bony bits, [George Mason University bioarchaeologist and LVBP director Haagen] Klaus and [Brigham Young University archaeology graduate student Connie] Ericksen write that “the general morphology of the bones could be described as unclassifiable in terms of normal human or general mammalian anatomy.” The dental tissue was “approximately the size of human deciduous teeth,” and looked like either small anterior teeth or large molar-like teeth, but “in most cases, occlusal anatomy was an irregular, highly variable arrangement of cusps and cusplets,” they write. […]

In the case of CNS U2-60, Klaus and Ericksen note that “it is not possible to determine if the lesion was benign or malignant, but a teratoma of this complexity and size likely impacted morbidity via impeded circulation.” She may not have died from the teratoma directly, but the large tumor probably made her appear pregnant and may have factored into her early death.

The Spanish woman was 30 to 40 years old when she died; the Roman woman (who was originally from the near East) was in a slightly wider age range, 25 to 45, at time of death. The fusion of her long bones indicate the Peruvian woman was in her late teens.