The resected specimen consisted of several lumps of fatty tissue, one of which contained a nidus of firm, gray tissue. Histology mainly showed sheets of adipocytes; however, disorganized neuroglial tissue, striated muscle fibres, some of which had a fetal appearance, and mature myelinated nerves were found in and around an area of fibrous tissue. Immature tubules (Image 2C x100) and clusters of uniform cells which formed glomeruloid structures (Image 2A x100) were also present in the fibrous tissue, highlighted by a hematoxylin van Gieson stain (Image 2B, x100). In some areas, the tubules were dilated to form cysts. Psammoma bodies were present (a feature in common with nephrogenic rests in the kidney). No undifferentiated (malignant) elements were found. Immunohistochemistry revealed that the glomeruloid structures contained cells that labeled with an antibody to vimentin. Capsules around these structures and tubules were immunoreactive for epithelial markers such as epithelial membrane antigen (EMA) (Image 2D x100). The disorganized neuroepithelial tissue labeled with an antibody to GFAP (Image 2E).
DIAGNOSIS AND DISCUSSION