MULTICYSTIC MESOTHELIOMA Figure 4-10 MULTICYSTIC MESOTHELIOMA This multicystic lesion has a more solid area on the left which represents morphologic overlap with an adenomatoid tumor. More

ADENOMATOID TUMOR Figure 4-11 ADENOMATOID TUMOR The lesion in the epididymis is circumscribed with a glistening solid cut surface. More

MULTICYSTIC MESOTHELIOMA Figure 4-6 MULTICYSTIC MESOTHELIOMA Multiple thin-walled, variably sized fluid-filled cysts are characteristic of this lesion. More

MESOTHELIOMA IN SITU Figure 3-19 MESOTHELIOMA IN SITU Top: The pleural surface is covered by a mildly atypical mesothelial proliferation. There is no invasion and no evidence of a mass lesion at surgery or on CT imaging. Bottom: Mesothelial cells show loss of BAP1 nuclear staining. More

CYSTIC TUMOR OF THE ATRIOVENTRICULAR NODE Figure 8-10 CYSTIC TUMOR OF THE ATRIOVENTRICULAR NODE Left: Within bundles of myocardium, nests of an epithelioid proliferation are seen. Right: This lesion is composed of bland tubules and solid nests. (Courtesy of Dr. J. Graham, New York, NY) More

SOLITARY FIBROUS TUMOR Figure 5-1 SOLITARY FIBROUS TUMOR Left: High-resolution computerized tomography (HRCT) with contrast shows a localized mass within the pleural space. An incidental superficial benign lesion is present in the right breast. Right: A rare site for solitary fibrous tumors is t... More

FIBRO-OBLITERATIVE DUCT LESION Figure 1-24 FIBRO-OBLITERATIVE DUCT LESION The bile duct has been replaced by a fibrous scar. More

GRANULOCYTIC EPITHELIAL LESION: SYPHILIS Figure 1-30 GRANULOCYTIC EPITHELIAL LESION: SYPHILIS The bile duct epithelium shows neutrophilic inflammation. There also is a cuff of plasma cell-rich inflammation surrounding the bile epithelium. More

GRANULOCYTIC EPITHELIAL LESION (GEL) Figure 3-8 GRANULOCYTIC EPITHELIAL LESION (GEL) This large bile duct is not dilated but has neutrophils in the duct epithelium. More

SYPHILIS Figure 3-11 SYPHILIS Left: This case of syphilis presented as a mass lesion and a biopsy showed changes of an inflammatory pseudotumor. Right: The T. pallidum immunostain is positive, showing slender bacteria. More

ECHINOCOCCOSIS MULTILOCULARIS Figure 3-23 ECHINOCOCCOSIS MULTILOCULARIS A resection for a mass lesion shows rare degenerating parasitic forms in the background of necrotizing granulomatous inflammation. More

FLORID DUCT LESION Figure 4-13 FLORID DUCT LESION This case of primary biliary cholangitis (PBC) shows an inflamed and injured bile duct surrounded by histiocyte-rich inflammation. More

FIBRO-OBLITERATIVE DUCT LESION Figure 7-17 FIBRO-OBLITERATIVE DUCT LESION In this case of cirrhosis from PSC, several bile ducts were replaced by round fibrous scars. More