Hepatoid Gland Adenoma
(PERIANAL ADENOMA, CIRCUMANAL GLAND ADENOMA)

A benign tumor of modified sebaceous glands found only in the dog.  On microscopic examination the cells morphologically resemble hepatocytes. These glands normally occur in the perianal area, tail, rearlimbs, back and preputial area, but occasionally may be found at other sites.

Gross Appearance:
•Elevated intradermal masses 
•Vary in size from 0.5-10.0 cm in diameter 
•Covered by hairless skin or often ulcerated and necrotic 
•Cut sections are pale brown and multilobulated 
•May show extensive hemorrhage and necrosis
•Invade underlying muscle and soft tissue

Histology:
•Trabeculae, islands and cords of tumor cells subdivided by a well vascularized connective tissue stroma 
•Surrounded by a connective tissue capsule
•Small basophilic reserve cells are found at the periphery of the tumor lobules 
•Reserve cells differentiate to cells with an abundant eosinophilic cytoplasm
•Cells have a central vesicular euchromatic nucleus and small nucleoli
•Mitoses are observed in the reserve cell layer
•Little nuclear atypia
•Ulceration, hemorrhage, necrosis and secondary infection with inflammatory cell infiltrates are common
•A proportion of cases will show foci of ductal differentiation (squamous metaplasia) 
•Foci of cytoplasmic lipidization (sebaceous differentiation)

Cytology: 
•Large, cuboidal epithelial cells 
•Occasionally isolated, but primarily found within adherent cell clusters
•Low nuclear:cytoplasm ratios; round nuclei; lacy chromatin; single, distinct nucleolus; occassionaly binucleate
•Mild anisocytosis and anisokaryosis
•Abundant, slightly granular blue cytoplasm
•Flattened reserve cells occasionally observed at the periphery of a cluster
•Cytologically, it can be difficult to distinguish hyperplasia, adenomas, and adenocarcinomas, since malignant tumors can appear cyotologically benign.

Prognosis:
Good; additional tumors represent de novo tumors not  recurrence

Breeds At Increased Risk
Breed Odds Ratio 95% Confidence Limit Probability
Bluetick Coonhound 4.477 1.882 - 10.647 0.004
Husky 3.887 3.468 - 4.357 0.001
Samoyed 3.108 2.517 - 3.837 0.001
Pekingese 2.731 2.056 - 3.627 0.001
Cocker Spaniel 2.277 2.089 - 2.481 0.001
Cockapoo 2.260 1.786 - 2.860 0.001
Brittany 1.942 1.524 - 2.474 0.001
Wirehaired Fox Terrier 1.862 1.229 - 2.818 0.007
Lhasa Apso 1.848 1.558 - 2.192 0.001
Shih Tzu 1.772 1.511 - 2.077 0.001
Newfoundland 1.747 1.191 - 2.563 0.008
Afghan Hound 1.600 1.059 - 2.418 0.036
Mixed Breed 1.546 1.469 - 1.628 0.001
Beagle 1.480 1.281 - 1.710 0.001
Irish Setter 1.333 1.063 - 1.671 0.015

 

Breeds At Decreased Risk
Breed Odds Ratio 95% Confidence Limit Probability
Yorkshire Terrier 0.761 0.591 - 0.978 0.031
English Springer Spaniel 0.702 0.562 - 0.877 0.001
German Shepherd 0.654 0.567 - 0.753 0.001
German Shorthaired Pointer 0.648 0.448 - 0.938 0.020
Bichon Frise 0.633 0.426 - 0.942 0.021
Standard Poodle 0.596 0.450 - 0.790 0.001
Labrador Retriever 0.563 0.500 - 0.636 0.001
Shetland Sheepdog 0.538 0.425 - 0.682 0.001
Miniature Schnauzer 0.530 0.410 - 0.685 0.001
Golden Retriever 0.474 0.416 - 0.541 0.001
Doberman Pinscher 0.464 0.382 - 0.564 0.001
Greyhound 0.463 0.239 - 0.894 0.014
Mastiff 0.455 0.215 - 0.961 0.034
Pug 0.439 0.235 - 0.820 0.005
Boston Terrier 0.410 0.242 - 0.695 0.001
Cardigan Welsch Corgi 0.379 0.157 - 0.916 0.022
Pointer 0.370 0.138 - 0.992 0.039
Scottish Terrier 0.347 0.221 - 0.547 0.001
Maltese 0.342 0.183 - 0.638 0.001
Bullmastiff 0.341 0.127 - 0.914 0.022
Jack Russel Terrier 0.312 0.148 - 0.657 0.001
Kerry Blue Terrier 0.311 0.116 - 0.834 0.009
English Setter 0.266 0.133 - 0.534 0.001
Soft-Coated Wheaton Terrier 0.240 0.089 - 0.641 0.001
American Pit Bull Terrier 0.235 0.111 - 0.494 0.001
Bull Terrier 0.175 0.044 - 0.705 0.002
Bouvier des Flandres 0.083 0.012 - 0.593 0.001
Boxer 0.080 0.048 - 0.136 0.001
Gordon Setter 0.076 0.011 - 0.539 0.001
Bernese Mountain Dog 0.069 0.010 - 0.490 0.001
Rottweiler 0.063 0.033 - 0.122 0.001
Shar-Pei 0.049 0.012 - 0.196 0.001

 

               Sex Distribution (N=6817)

Sex Status

Percent

Male

(45.0%)

72.8%
intact

(28.1%)

 52.8
neutered

(16.9%)

 20.0
Female

(55.0%)

27.2%
intact

(23.9%)

 8.7
neutered

(31.1%)

 18.5
(normal sex distribution)

 
Anatomic Location (N=)
Site

Percent

Perineum  85.3
Tail  7.1
Multiple  3.6
Abdomen  3.1
Back  0.8
Hindlimb 0.1
 


Copyright © 2000 - University of Pennsylvania School of Veterinary Medicine
Faculty: Michael H. Goldschmidt, BVMS & Patricia Mcmanus,VMD, PhD
Student: Kyle Goldschmidt
Comments: goldsch@vet.upenn.edu