Plasma Cell Tumor
(CUTANEOUS PLASMACYTOMA)

These tumors show differentiation to plasma cells within the skin.

Gross Appearance:
•Solitary tumors 
•Intradermal nodules
•Alopecia
•Elevated lesions often have a bright red appearance
•No evidence of encapsulation
•Margin of the tumor may be readily delineated

Histology:
•Tumor may abutt against the dermo-epidermal junction 
•Does not infiltrate the epidermis
•Grenz zone between the tumor and the epidermis
•At the periphery of the tumor, infiltration between the dermal collagen by rows and cords of tumor cells may be seen
•Neoplastic cells may form large sheets or large nests surrounded by a fine fibrovascular stroma
•Tumor cells may be monomorphic or pleomorphic
•All have cytologic features of plasma cells:
•Round hyperchromatic nuclei 
•Clumped peripheral chromatin
•Small central nucleolus
•Amphophilic cytoplasm
•Distinct cell borders
•Marked nuclear and cellular pleomorphism
• Binucleate, multinucleate and karyomegalic cells are present
•Mitotic activity is usually quite low
•Amyloid deposition within the cutaneous plasmacytoma is an uncommon occurrence
•Amyloid may be deposited as small foci surrounded by the neoplastic plasma cells 
•Or as large sheets devoid of neoplastic cells
•Granulomatous response may be diffusely scattered throughout the tumor

Cytology:

 

               Sex Distribution (N=1057)

Sex Status

Percent

Male

(45.0%)

51.4%
intact

(28.1%)

 23.5
neutered

(16.9%)

 27.9
Female

(55.0%)

48.6%
intact

(23.9%)

 15.6
neutered

(31.1%)

 33.0
(normal sex distribution)

 
Anatomic Location (N=971)
Site

Percent

Head  38.5
Hindlimb  19.1
Forelimb  15.6
Abdomen  10.5
Thorax  4.6
Multiple  3.9
Perineum  2.9
Neck  2.7
Back  1.0
Tail  0.9
 


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