A Schiller–Duval body is a cellular structure seen by microscope

Microscope

A microscope is an instrument used to see objects that are too small for the naked eye. The science of investigating small objects using such an instrument is called microscopy...

 in endodermal sinus tumor

Endodermal sinus tumor

Endodermal sinus tumor , also known as yolk sac tumor , is a member of the germ cell tumor group of cancers. It is the most common testicular tumor in children under 3, and is also known as infantile embryonal carcinoma. This age group has a very good prognosis...

s (yolk sac tumors) which are the most common testicular cancer in children. Schiller-Duval bodies are present in approximately 50% of these tumors, and if found are pathognomonic

Pathognomonic

Pathognomonic is a term, often used in medicine, that means characteristic for a particular disease. A pathognomonic sign is a particular sign whose presence means that a particular disease is present beyond any doubt...

. They are named for Mathias-Marie Duval

Mathias-Marie Duval

Mathias-Marie Duval was a French professor of anatomy and histology born in Grasse. He was the son of botanist Joseph Duval-Jouve .He studied medicine in Paris, and later served as prosector in Strassburg...

 and Walter Schiller

Walter Schiller

Walter Schiller was an austrian-born American pathologist. He published primarily in the field of gynaecological cancer, and described Schiller's test and Schiller-Duval bodies.- Biography :...

  who described them in the late nineteenth century.

Schiller–Duval bodies are said to resemble a glomerulus

Glomerulus

A glomerulus is a capillary tuft that is involved in the first step of filtering blood to form urine.A glomerulus is surrounded by Bowman's capsule, the beginning component of nephrons in the vertebrate kidney. A glomerulus receives its blood supply from an afferent arteriole of the renal...

. They have a mesoderm

Mesoderm

In all bilaterian animals, the mesoderm is one of the three primary germ cell layers in the very early embryo. The other two layers are the ectoderm and endoderm , with the mesoderm as the middle layer between them.The mesoderm forms mesenchyme , mesothelium, non-epithelial blood corpuscles and...

al core with a central capillary

Capillary

Capillaries are the smallest of a body's blood vessels and are parts of the microcirculation. They are only 1 cell thick. These microvessels, measuring 5-10 μm in diameter, connect arterioles and venules, and enable the exchange of water, oxygen, carbon dioxide, and many other nutrient and waste...

, all lined by flattened layers of both visceral and parietal cells. Immunofluorescent

Immunofluorescence

Immunofluorescence is a technique used for light microscopy with a fluorescence microscope and is used primarily on biological samples. This technique uses the specificity of antibodies to their antigen to target fluorescent dyes to specific biomolecule targets within a cell, and therefore allows...

 stain may show eosinophilic hyalin

Hyalin

Hyalin is a protein released from the cortical granules of a fertilized animal egg. The released hyalin modifies the extracellular matrix of the fertilized egg to block other sperm from binding to the egg, and is known as the slow-block to polyspermy. All animals have this slow-block...

-like globules both inside and outside the cytoplasm

Cytoplasm

The cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the cytoplasm...

 that contain AFP

Alpha-fetoprotein

Alpha-fetoprotein is a protein that in humans is encoded by the AFP gene....

 and alpha 1-antitrypsin

Alpha 1-antitrypsin

Alpha 1-Antitrypsin or α1-antitrypsin is a protease inhibitor belonging to the serpin superfamily. It is generally known as serum trypsin inhibitor. Alpha 1-antitrypsin is also referred to as alpha-1 proteinase inhibitor because it inhibits a wide variety of proteases...

.