Neurofibroma Amitabh Srivastava, MD Key Facts Terminology Benign peripheral nerve sheath tumor with heterogeneous admixture of axons, Schwann cells, perineurial cells, and fibroblasts Most are sporadic; NF1 associated with multiple,…

Schwannoma Amitabh Srivastava, MD Key Facts Terminology Encapsulated, benign peripheral nerve sheath tumor composed predominantly of Schwann cells Clinical Issues Common between 20-50 years of age Affects males and females…

Neuroma Thomas Mentzel, MD Key Facts Terminology Neuroma represents proliferation of peripheral nerve fibers in which ratio of axons to Schwann cell fascicles approaches 1:1 Solitary circumscribed neuroma (“palisaded encapsulated…

Fibrolipomatous Hamartoma Cyril Fisher, MD, DSc, FRCPath Key Facts Terminology Increased fibrofatty tissue infiltrating and surrounding nerves Clinical Issues Median nerve most commonly affected Predominantly in children, including congenitally Macrodactyly…

Myoepithelioma/Mixed Tumor/Parachordoma Thomas Mentzel, MD Key Facts Terminology Neoplasms that are composed of epithelial &/or myoepithelial cellular elements in varying proportions Tumor cells are set in hyalinized to chondromyxoid stroma…

Malignant Mesothelioma Cyril Fisher, MD, DSc, FRCPath Key Facts Terminology Malignant tumor of mesothelial cells arising in pleura, peritoneum, or pericardium Etiology/Pathogenesis Asbestos exposure Amphibole: Crocidolite, amosite Thin long fibers…

Well-Differentiated Papillary Mesothelioma Cyril Fisher, MD, DSc, FRCPath Key Facts Clinical Issues Rare Peritoneal lesions mostly in females Occasionally paratesticular in males Solitary or multiple Rarely recur after long period…

Multicystic Peritoneal Mesothelioma Cyril Fisher, MD, DSc, FRCPath Key Facts Terminology Benign intraabdominal or pelvic lesion of parietal or serosal peritoneal mesothelium Etiology/Pathogenesis Minimal association with previous exposure to asbestos…

Adenomatoid Tumor Cyril Fisher, MD, DSc, FRCPath Key Facts Terminology Benign mesothelial tumor Clinical Issues Usually solitary, rarely multiple Most common in 4th-7th decades Most common in male and female…