Amorphous globosus

An amorphus globosus (from Greek αμορφή (amorphē, 'formless') and Latin globus ('sphere')), also known as a globosus amorphus,^[1] or an amorphous globosus monster,^[1] is a malformation occurring in veterinary medicine, especially in domestic cattle. Instead of a normally developed fetus, it results in the formation of a more or less spherical structure covered with hairy skin, which contains parts of all three germ layers; the differentiation of its contents can vary greatly. An amorphus globosus is not viable due to the lack of functional organs.^[2]

A bovine amorphus globosus

Origin

The teratological reasons for the development of amorphus globosus are not fully understood, but it is believed that the malformation is generally associated with twin gestation,^[3] in which one embryo does not develop normally. In two cases, the karyotype of the amorphus was identical to its normally developing twin,^[4][5] while in another case, the karyotype deviated from the normal twin,^[6] so an emergence from fraternal twins also seems possible.

Distribution

Amorphus globosus is more common in livestock than generally assumed.^[2] It occurs most commonly in cattle, but there are also case reports in goats^[2] and horses.^[7] A case of amorphus globosus has also been described in human medicine, where it was also a twin pregnancy.^[8]

See also

• Birth defect
• Twin reversed arterial perfusion
• Schmallenberg orthobunyavirus