Meconium is the earliest stool of a mammalian infant resulting from defecation. Unlike later feces, meconium is composed of materials ingested during the time the infant spends in the uterus: intestinal epithelial cells, lanugo, mucus, amniotic fluid, bile, and water. Meconium, unlike later feces, is viscous and sticky like tar – its color usually being a very dark olive green and it is almost odorless. When diluted in amniotic fluid, it may appear in various shades of green, brown, or yellow. It should be completely passed by the end of the first few days after birth, with the stools progressing toward yellow (digested milk). Clinical significance
Meconium in amniotic fluid
Meconium is normally retained in the infants bowel until after birth, but sometimes it is expelled into the amniotic fluid (also called "amniotic liquor") prior to birth or during labor and delivery. The stained amniotic fluid (called "meconium liquor" or "meconium-stained liquor") is recognized by medical staff as a possible sign of fetal distress. Some post-dates pregnancies (when they are more than 40 weeks pregnant) may also have meconium-stained liquor without fetal distress. Medical staff may aspirate the meconium from the nose and mouth of a newborn immediately after delivery in the event the baby shows signs of respiratory distress to decrease the risk of meconium aspiration syndrome, which can occur in meconium-stained amniotic fluid. Most of the time that the amniotic fluid is stained with meconium, it will be homogeneously distributed throughout the fluid, making it brown.
Endodermal sinus tumor (EST) is a member of the germ cell tumor group of cancers. It is the most common testicular tumor in children under three, and is also known as infantile embryonal carcinoma. This age group has a very good prognosis. In contrast to the pure form typical of infants, adult endodermal sinus tumors are often found in combination with other kinds of germ cell tumor, particularly teratoma and embryonal carcinoma. While pure teratoma is usually benign, endodermal sinus tumor is malignant. Cause
Causes for this cancer are poorly understood. Diagnosis
The histology of EST is variable, but usually includes malignant endodermal cells. These cells secrete alpha-fetoprotein (AFP), which can be detected in tumor tissue, serum, cerebrospinal fluid, urine and, in the rare case of fetal EST, in amniotic fluid. When there is incongruence between biopsy and AFP test results for EST, the result indicating presence of EST dictates treatment. This is because EST often occurs as small "malignant foci" within a larger tumor, usually teratoma, and biopsy is a sampling method; biopsy of the tumor may reveal only teratoma, whereas elevated AFP reveals that EST is also present. GATA-4, a transcription factor, also may be useful in the diagnosis of EST.Diagnosis of EST in pregnant women and in infants is complicated by the extremely high levels of AFP in those two groups. Tumor surveillance by monitoring AFP requires accurate correction for gestational age in pregnant women, and age in infants.