HISTOLOGIC LOOK-ALIKES

Lymph Node vs Parathyroid Gland

• Lymph Node-
  
• 1. Medullary cords prominent (not shown)
• 2. Lymph sinuses prominent
• 3. Large subcapsular sinus
• 4. Many lymphoid follicles

• Parathyroid Gland-
  
• 1. Chief cells in cords resemble lymphocytes
• 2. Prominent capillary bed, no lymph sinuses
• 3. Some oxyphil cells
• 4. No lymphoid tissue
• 5. Adipose cells (post puberty)
• 6. No cortex/medulla

Thyroid vs Active Mammary Gland

• Thyroid-
  
• 1. Clear hyaline colloid in follicles
• 2. Vacuoles may be present in colloid
• 3. No ducts
• 4. No lobules
• 5. Islets of parafollicular cells

• Active Mammary Gland-
  
• 1. Granular or hyaline secretion in expanded alveoli
• 2. Fat droplets (vacuoles) in alveoli and ducts
• 3. Excretory ducts present
• 4. Lobulated

Epinephrine vs Norepinephrine Granules

• Epinephrine Granules-
  
• 1. Less electron-dense core
• 2. Light and dark granules
• 3. Even distribution in cell
• 4. Each granule fills a spherical vesicle

Norepinephrine Granules-

• 1. Very electron-dense core-often eccentric in position
• 2. Often in clusters, uneven distribution in cell
• 3. Size and shape less uniform