Osler Institute Pathology Board Review Electron Microscopy EM

Osler Institute – Pathology Board Review: Electron Microscopy EM of Tumors and Tumor-Like Entities

Osler Institute – Pathology Board Review: Electron Microscopy Acinar Cell Carcinoma • • • Zymogen granules 0. 3 – 1. 5 microns Stacks of RER Salivary gland Pancreas Pancreaticoblastoma Immunopositive for alpha-1 antitrypsin Trypsin Chymotrypsin Lipase

Osler Institute – Pathology Board Review: Electron Microscopy Adenocarcinoma – extracellular lumina, intestinal type microvilli

Osler Institute – Pathology Board Review: Electron Microscopy Neoplasms Adenocarcinoma • Intracytoplasmic lumina • Microvilli • Junctional complexes

Osler Institute – Pathology Board Review: Electron Microscopy Neoplasms

Electron Microscopy - Osler Institute Pathology Board Review Neoplasms Bronchioloalveolar Cell carcinoma Type II Pneumocyte • Myelin figures • Microvilli Clara Cells • Secretory granules

Electron Microscopy - Osler Institute Pathology Board Review Neoplasms Carcinoid (Neuroendocrine) Tumors • Dense core granules 140 – 400 nm • True lumens • Intracytoplasmic filaments

Electron Microscopy - Osler Institute Pathology Board Review Eosinophilic Granuloma Langerhan’s cell histiocyte • Rod shaped Birbeck Granule • Pleomorphic, deeply cleaved nucleus

Electron Microscopy - Osler Institute Pathology Board Review Neoplasms Ependymoma • 5 – 7% of intracranial neuroglial neoplasms • 60% of neuroglial tumors in spinal cord • Most common sites – fourth ventricle and lumbosacral region • Flexner type rosettes True lumens – cilia, microvilli and junctional complexes

Electron Microscopy - Osler Institute Pathology Board Review Neoplasms Ependymoma • Junctional complexes • Intracytoplasmic lumina • Intracytoplasmic glial filaments • Immunopositive for GFAP

Electron Microscopy - Osler Institute Pathology Board Review Neoplasms Granular Cell Tumor • Pleomorphic secondary lysosomes • Basal lamina around cell groups

Electron Microscopy - Osler Institute Pathology Board Review Neoplasms Granular Cell Tumor • Angulate lysosomes in stromal fibrohistiocytic cells

Electron Microscopy - Osler Institute Pathology Board Review Neoplasms Hibernoma • Lipid droplets • Electron dense mitochondria • S-100 protein + • Vimentin +

Electron Microscopy - Osler Institute Pathology Board Review Lymphoma Non Hodgkin's Type • No junctional complexes • Few cytoplasmic organelles • Abundant polyribosomes

Electron Microscopy - Osler Institute Pathology Board Review Lymphoma Non Hodgkin's Type • No junctional complexes • Few cytoplasmic organelles • Abundant polyribosomes

Electron Microscopy - Osler Institute Pathology Board Review Neoplasms Mesotheliomas • • • Long thin microvilli Bipolar cytoplasmic processes Desmosomes Primitive junctions Calretinin + Mesothelin +