Normal Anatomy The bladder is a hollow viscus with the shape of a four-sided inverted pyramid when empty and of a rounded structure when distended. It is divided into the following portions: superior surface (also known as dome , and…
Pediatric Tumors and Tumorlike Conditions Nephroblastic Tumors Wilms Tumor (Nephroblastoma) General Features Wilms tumor is also known as nephroblastoma (currently the preferred term). It constitutes the prototypical example of a neoplastic process that faithfully recapitulates embryogenesis at the morphologic and…
Renal Biopsy Renal biopsy is an important tool used in the evaluation of patients with renal disease. Utilizing this procedure, it is possible to establish an accurate diagnosis, obtain critical information on the evolution and prognosis of the disease process,…
Pancreas Normal Anatomy The pancreas forms from two separate buds or anlagen , which later rotate and fuse. The ventral bud, which appears as a part of the developing hepatic duct, forms the posterior and inferior parts of the head…
Normal Anatomy The gallbladder is a pear-shaped sac that lies in a shallow depression on the inferior surface of the right hepatic lobe. In the adult, it measures up to 10 cm in length and 3–4 cm in width, and the normal…
Hepatic Tumors and Tumorlike Conditions Surgical pathologists encounter a wide variety of nodules and tumors of hepatic origin, including both neoplastic and non-neoplastic lesions. Distinguishing between them can be challenging, but the distinction is critically important given the differing prognostic…
Normal Anatomy Several structural and functional units have been proposed in the microanatomy of the liver. Of these, the most relevant for the diagnostic histopathologist are the liver lobule and the liver acinus. For several years the liver acinus was…
Normal Anatomy of the Anus The anus and anal canal comprise a complex anatomic region with historically controversial nomenclature, due to the fact that the extent of the zones from person to person is variable and that the macroscopic and…
Normal Anatomy of the Large Bowel The large bowel comprises the terminal 1–1.5 m of the gastrointestinal tract and is divided into the following regions: cecum, ascending (right) colon, transverse colon, descending (left) colon, sigmoid colon, and rectum. The hepatic flexure…
Normal Anatomy of the Appendix The vermiform appendix is a tubular structure arising from the medial wall of the cecum; it averages 9 cm in length and 0.7 cm in greatest diameter, although the luminal dimensions may vary along the length of…