+ General Considerations
- Sebaceous gland tumors are subdivided into adenomatous hyperplasia, epithelioma, adenoma, or ADC according to the level of cellular maturation
- Modified sebaceous glands include eyelid meibomian gland and perianal gland
- Sebaceous gland tumors are rare in cats (2.3%-4.4%), but common in dogs (6.8%-7.9%)
+ Adenomatous Hyperplasia
- Sebaceous hyperplasia can progress to sebaceous adenoma or ADC and may be a precursor to their development
- Breed predisposition: Beagle, Cocker Spaniel, Poodle, and Miniature Schnauzer
- Sex predisposition: males in cats and dogs
- Androgen influence is suspected in pathophysiology and hyperadrenocorticism should be assessed in female dogs and dogs with recurrent adenomatous hyperplasia of the sweat glands
- Gross appearance: solitary (± multiple) and grossly indistinguishable from adenoma
- Sites: head in cats and limbs, trunk, and eyelids in dogs
- Treatment: surgery
- Prognosis: good with local tumor recurrence rare (1.1%) but de novo tumor development in up to 10%
+ Sebaceous Epithelioma
- Breed predisposition: Shih Tzu, Lhasa Apso, Alaskan Malamute, Siberian Husky, and Irish Setter
- Solitary form occurs primarily on the head and particularly the eyelids
- Generalized form has been reported
- Treatment: surgery
- Prognosis: good with local tumor recurrence rate 6%
+ Sebaceous Gland Adenoma
- Breed predisposition: Cocker Spaniel, Springer Spaniel, Boston Terrier, and Wire-Haired Terrier
- Gross appearance and biologic behaviour similar to adenomatous hyperplasia
- Sites: head
- Treatment: surgery
+ Sebaceous Gland Adenocarcinoma
- Rapid growth rate and ulceration
- Site: perianal
- Gross appearance: solitary, poorly circumscribed, ulcerated, and invasive
- Local tumor recurrence and metastasis risk varies from low to 70%-90%