Objectives

1

• Objectives
• Detect and recognize cytoplasmic organelles and
  matrix
• Interpret the ultrastructural features of
  commonly encountered tumors, non neoplastic
  entities and infectious agents
• Guide to tissue submission
• Undifferentiated malignant tumors Small cell
  malignancies
• Neuroendocrine tumors CNS tumors
• Anomalous IHC results Select IHC panel
• Eosinophilic granuloma Renal biopsies
• Heart biopsies Nerve biopsies
• Bullous diseases of skin Storage diseases
• Rapid diagnosis of viral infection Ciliary
  dysmorphology
• Extracellular matrix

2

• Processing tissue for electron microscopy
• 1 mm cubed tissue pieces
• Dehydrate, infiltrate, osmicate, embed in plastic
• Toluidine blue thick sections
• Thin sections 100 nm on copper grids (silver
  sections)
• Interpretation of electron micrographs
• Determine approximate magnification
• Identify organelles
• Integrate ultrastructural features with clinical
  history, light microscopy, IHC and molecular
  diagnostics
• Limitations of electron microscopy
• Sample size
• Multidirectional differentiation
• No diagnostic organelles

3

• Primer of Organelles
• Nucleus
• Abundant heterochromatin Ewings sarcoma, B cell
  lymphoma
• Cerebriform nuclear contours
• Nuclear pseudoinclusions nuclear pockets
• Intranuclear tubular aggregates
• Nucleolus
• Meandering reticular nucleoli seminoma,
  dysgerminoma
• Marginated Nucleolus
• Increased nucleoli

Slide 3
4

• Primer of Organelles
• Cytoplasm
• Annulate lamellae Cylindrical confronting
  cisternae
• Cytoskeleton Endoplasmic reticulum
• Golgi Intercellular junctions
• Lamellar cytoplasmic inclusions Lipid
• Langerhans cell granules Lysosomes
• Melanosomes Microvilli
• Mitochondria Ribosomes and polyribosomes
• Secretory granules Tubular reticular structures
• Weibel Palade bodies
• Extracellular Matrix
• Amyloid
• Collagen