|
ETIOLOGY / EMBRYOLOGY
OF SACROCOCCYGEAL
TERATOMA (SCT) |
Sacrococcygeal teratomas originate from Hensen's node (primitive knot), which is an area of the primitive streak. Hensen's node is an aggregation of totipotential cells that are the primary organizers of embryonic development.
As the mesoderm proliferates, the primitive steaks moves further caudally where the remnant of Hensen's node descends to the tip of the coccyx or its anterior surface (segregation of totipotential cells from Hensen's node probably gives rise to sacrococcygeal teratomas). These pleuripotential cells escape from the control of embryonic inducers and organizers and differentiate into tissues not usually found in the sacrococcygeal region. The primitive streak diminishes in size and becomes an insignificant structure in the sacrococcygeal region of the embryo, eventually disappearing.
The primitive streak remnant may persist and give rise to a sacrococcygeal teratoma. Being a teratoma, they have the potential to contain various amounts of ectoderm, mesoderm and endoderm.
>90% are benign.
The prevalence of malignancy increases with age (overall prevalence of malignant elements in 2% of neonates compared with 60% of infants with a diagnosis at 4 months of age (3).
The primary cause of death in neonatal SCT is malignant invasion, which occurs in about 7-`3% of cases.
The tumor occurs near the coccyx,
where the greatest concentration of primitive cells exists for the longest
period of time during development.
Histologically they contain squamous epitehelium and other skin elements, neuronal tissue, fat, mucus, striated muscle, cartilage, and occasionally bone and mandibular structures.
REFERENCES |