Osler Institute – Pathology Board Review: Electron Microscopy

EM of Tumors and Tumor-like Entities

Electron Microscopy - Osler Institute Pathology Board Review

Neoplasms

Oncocytoma

• Salivary gland• Parotid• Kidney

Electron Microscopy - Osler Institute Pathology Board Review

Neoplasms

Oncocytoma

• Pleomorphic mitochondria

• Lamelliform (plate like) mitochondrial cristae

• Dense bodies in mitochondria

Electron Microscopy - Osler Institute Pathology Board Review

Neoplasms

Plasmacytoma

• NucleiMarginated heterochromatin

• Prominent profiles of rough endoplasmic reticulum

• Immunoglobulin inclusions in RER and nucleus

Electron Microscopy - Osler Institute Pathology Board Review

Neoplasms

Renal Cell Carcinoma(conventional type)

• Long microvilli• Glycogen• Lipid droplets

Electron Microscopy - Osler Institute Pathology Board Review

Neoplasms

Renal Cell Carcinoma

Chromophobe Type• Microvesicles• Hale’s colloidal iron positive

Papillary (chromophil) Type• Abundant mitochondria

Electron Microscopy - Osler Institute Pathology Board Review

Neoplasms

Seminoma

• Wandering, ropy, nucleolus• Finely dispersed

heterochromatin• Inconspicuous organelles• Intercellular junctions

Electron Microscopy - Osler Institute Pathology Board Review

Neoplasms

Squamous cell carcinoma

• Desmosomes• Tonofilament bundles

Electron Microscopy - Osler Institute Pathology Board Review

Small Round Cell Tumors

Electron Microscopy - Osler Institute Pathology Board Review

Neoplasms

Small Round Cell Tumors

Ewings Sarcoma

• Dispersed heterochromatin

• Small nucleolus

Electron Microscopy - Osler Institute Pathology Board Review

Neoplasms

Small Round Cell Tumors

Ewings Sarcoma

• Large pools of glycogen

Electron Microscopy - Osler Institute Pathology Board Review

Neoplasms

Small Round Cell Tumors

Rhabdomyosarcoma

• Actin-myosin filaments with Z-band

• Primitive sarcomeres

Electron Microscopy - Osler Institute Pathology Board Review

Neoplasms

Small Round Cell Tumors

Rhabdomyosarcoma

• Ribosome-filament complexes

• Small primitive junctions

• External lamina

Electron Microscopy - Osler Institute Pathology Board Review

Neoplasms

Small Round Cell Tumors

Neuroblastoma

• Cell processes • Secretory granules• Microtubules• Neurofilaments

Electron Microscopy - Osler Institute Pathology Board Review

Neoplasms

Small Round Cell Tumors

Lymphoma (Follicular Center Cell)

• No cell junctions