Skin 5

• What is a Nevus in the context of skin pathology?

  A benign growth caused by focal hyperplasia of hair follicles.
• What is the typical presentation of sebaceous gland hyperplasia?

  • Multiple wart-like masses
  • Commonly seen on eyelids and limbs of dogs
  • Especially in breeds like Cocker Spaniels, Beagles, and Poodles
• What can happen if a Nevus leads to follicle rupture?

  It can cause inflammation.
• What can occur if a follicular cyst ruptures?

  It can cause inflammation.
• What is a follicular cyst?

  A benign, malformed hair follicle filled with keratin.
• What is calcinosis circumscripta?

  A localized area of calcification.
• Where are histiocytomas most commonly found in dogs?

  On the head and extremities of young dogs.
• What characterizes a histiocytoma in dogs?

  A benign skin tumor characterized by the proliferation of macrophages.
• What is a lipoma?

  A benign fatty tumor.
• In which breed is calcinosis circumscripta most commonly seen?

  In young large breeds, such as German Shepherds.
• What is a hemangioma?

  A vascular tumor that is solar-induced.
• Where is a lipoma most commonly found?

  Subcutaneously in dogs and cats.
• How is a hemangioma typically mistaken clinically?

  It is commonly mistaken for melanomas due to its dark purple color.
• Where is sebaceous adenoma commonly found in dogs?

  Around the eyelids.
• What type of cells give rise to basal cell tumors (trichoblastomas)?

  Follicular epithelial cells at the base of hair follicles.
• What is a key feature of follicular tumors?

  They usually contain keratin.
• Where are basal cell tumors most commonly located?

  Around the head.
• What can happen if follicular tumors rupture?

  They can rapidly increase in size and ulcerate.
• Where is squamous cell carcinoma most likely to develop in dogs and cats?

  In non-pigmented areas, often induced by sunlight.
• What are common sites for squamous cell carcinoma in cats?

  Ears, eyelids, and nose.
• What is a key characteristic of perianal gland adenomas in dogs?

  They are testosterone-responsive.
• In which dogs are perianal gland adenomas more common?

  In intact male dogs.
• How does mammary tumor incidence differ between dogs and cats?

  Canine mammary tumors are often benign, while feline mammary tumors are mostly malignant.
• What is the grading system for canine mast cell tumors (MCTs)?

  The Patnaik system.
• What characterizes Grade I mast cell tumors in the Patnaik system?

  Well-differentiated, confined to the dermis.
• What characterizes Grade III mast cell tumors in the Patnaik system?

  Poorly differentiated, invasive, with a poor prognosis.
• Where are plasmacytomas commonly found in dogs?

  Primarily in the mouth, feet, and pinnae.
• What is the nature of most plasmacytomas in dogs?

  Most are benign.
• What causes equine sarcoids?

  They are caused by bovine papillomavirus.
• Where do equine sarcoids typically develop?

  Around the head and limbs in younger horses.
• What is a key characteristic of equine sarcoids?

  They are non-metastatic but tend to be recurrent after excision.