Eyes, Head, Neck

• Sections of the lecture outline


  • Eyes
  • Head and Neck
  • References
• Subsections of the Eyes section


  • Orbit
  • Eyelid
  • Conjunctiva
  • Sclera
  • Cornea
  • Anterior Segment
  • Uvea
  • Retina and Vitreous
  • Optic Nerve
  • Phthisis Bulbi

  
• Proptosis


  Diseases that increase orbital contents that displace the eye forward
• Proptotic eye


  • Might not be covered completely by the eyelids, and the tear film might not be distributed evenly across the cornea
  • Chronic corneal exposure to air is injurious, leading to pain and predisposing to corneal ulceration and infection

  
• Types of Proptosis


  • Axial- pushes eye directly forward
  • Positional- displaces orbit inferiorly and medially
• Thyroid Ophthalmopathy (Graves Disease)


  • Proptosis is caused by the accumulation of extracellular matrix proteins and variable degrees of fibrosis in the rectus muscles
  • Development of thyroid ophthalmopathy may be independent of the status of thyroid function
• Other Orbital Inflammatory Conditions


  • Uncontrolled sinus infection
  • Systemic conditions: granulomatosis with polyangiitis (Wegener's)
  • Inflammatory pseudotumor
• Inflammatory pseudotumor


  May be unilateral or bilateral and may affect all orbital tissue elements or may be confined to the lacrimal gland, Extraocular muscles, or Tenon capsule
• IgG4-related disease should be excluded before declaring an orbital inflammation to be idiopathic
• Morphologic findings in idiopathic orbital inflammation


  • Chronic inflammation and variable degrees of fibrosis
  • Germinal centers suggest reactive lymphoid hyperplasia
  • Vasculitis suggests an underlying systemic condition
  • Presence of necrosis and degenerating collagen along with vasculitis suggests granulomatosis with polyangiitis
• Types of orbital neoplasms


  • Vascular (most common)
  • Encapsulated orbital masses
  • Metastatic
• Non-Hodgkin lymphoma can affect the entire orbit or can be confined to compartments of the orbit such as the lacrimal gland
• Primary orbital malignancies may arise from any of the orbital tissues and are classified according to the scheme used for the parent tissue
• Eyelid


  Composed of skin externally and mucosa (conjunctiva) on the surface apposed to the eye

  
• Blepharitis


  Chronic inflammation at the eyelid margin due to obstruction of the drainage system of the sebaceous glands

  
• Lipogranuloma or chalazion


  Caused by lipid extravasation into surrounding tissue provoking a granulomatous response
• Eyelid neoplasms


  • Primary melanomas of the eyelid skin are extremely rare
  • May distort tissue and prevent the eyelids from closing completely

  
• Clinicopathologic features of eyelid neoplasms


  • Basal Cell Carcinoma
  • Sebaceous carcinoma
  • Kaposi sarcoma

  
• Palpebral conjunctiva


  Lines the interior eyelid and may respond to inflammation by being thrown into minute papillary folds

  
• Conjunctiva in the fornix


  PSCE rich in goblet cells, most noticeable area of lymphoid population
• Bulbar conjunctiva


  Covers the surface of the eye lined by NKSSE

  
• Limbus


  Intersection between the sclera and cornea, also marks the transition between conjunctival and corneal epithelium
• Malignant neoplasms tend to spread to regional lymph nodes (parotid and submandibular node groups)
• Conditions associated with conjunctival scarring


  • Chlamydia trachomatis (trachoma)
  • After exposure of the ocular surface to caustic alkalis
  • Sequela to ocular cicatricial pemphigoid
  • Iatrogenic (drugs or surgery)
• Dry eye


  Deficiency in the aqueous component of the tear film generated by the accessory lacrimal glands embedded within the eyelid and fornix

  
• Extensive surgical excision of diseased conjunctiva can remove a large number of goblet cells or compromise lacrimal gland ductules, causing a painful dry eye that can compromise vision

  
• Differences between pinguecula and pterygium


  • Origin
  • Histology
  • Focal dehydration
  • Inflammation
• Conjunctival neoplasms


  • Conjunctival Squamous Cell Carcinoma
  • Conjunctival Nevi
  • Conjunctival Melanomas
• Conjunctival Squamous Cell Carcinoma


  Intraepithelial neoplastic changes analogous to those seen in the evolution of cervical squamous cell carcinoma
• Conjunctival Nevi


  Pigmented lesions that characteristically contain subepithelial cysts lined by surface epithelium
• Conjunctival Melanomas


  Unilateral neoplasms, typically affecting fair-complexioned individuals in middle age, most cases develop through primary acquired melanosis with atypia or conjunctival melanocytic intraepithelial neoplasia, BRAF V600 mutations may be identified in nearly 40%, best treatment is its prevention through extirpation of its precursor lesion, spreads first to the parotid or submandibular lymph nodes, 25% prove to be fatal
• Sclera


  Consists mainly of collagen and contains few blood vessels and fibroblasts, wounds and surgical incisions tend to heal poorly, prone to rupture-thin at limbus and around optic nerve
• Conditions that can make the sclera appear "blue"


  • Necrotizing scleritis
  • Staphyloma
  • Osteogenesis imperfecta
  • Congenital melanosis oculi
  • Nevus of Ota
• Cornea


  Makes up the major refractive surface of the eye, diseases of refraction include myopia and hyperopia, laser-assisted in situ keratomileusis (LASIK) sculpts the cornea and changes its refractive properties

  
• Corneal epithelium


  • Rests on a basement membrane, Bowman layer forms an efficient barrier against the penetration of malignant cells from the epithelium into the underlying stroma
• Corneal stroma


  Lacks blood vessels and lymphatics, contributes to the transparency of the cornea and high rate of success of corneal transplantation, normally in a state of relative deturgescence (dehydration)
• Corneal vascularization may accompany chronic corneal edema, inflammation, and scarring, VEGF antagonists afford a promising approach to preventing corneal vascularization
• Scarring and edema both disrupt the spatial alignment of stromal collagen and contribute to corneal opacification
• Non-immune graft rejection is more common with inflammation and vascularization in corneal transplants
• Causes of corneal ulcerations


  • Bacterial
  • Fungal
  • Viral (HSV and HZV)
  • Protozoal (Acanthamoeba)