Use of Oil Red O stain in the cytologic diagnosis of canine liposarcoma.
BACKGROUND
Oil Red O, a stain commonly used to demonstrate lipid in frozen tissue, also may be used to stain air-dried cytologic specimens.


OBJECTIVE
The purpose of this study was to prospectively evaluate the value of Oil Red O in identifying lipid to aid in the differentiation of liposarcomas from other types of sarcoma.


METHODS
Twelve tumor specimens from dogs were evaluated. The tumors were included in the study if initial cytologic evaluation indicated a sarcoma, and if histologic confirmation was available. Oil Red O was applied to all cytologic specimens.


RESULTS
Tumor specimens were diagnosed histologically as liposarcoma (3 well-differentiated, 1 pleomorphic), hemangiopericytoma (n = 3), fibrosarcoma (n = 3), malignant fibrous histiocytoma (n = 1), and undifferentiated sarcoma (n = 1). Cytologic specimens from all liposarcomas showed strong positive staining of cytoplasmic vacuoles for lipid. Specimens from other sarcomas stained negative for Oil Red O, with the exception of weak, irregular positive staining in 1 hemangiopericytoma.


CONCLUSIONS
Our results suggest that Oil Red O staining may be an easy, inexpensive, and useful diagnostic tool for the differentiation of liposarcoma from other mesenchymal neoplasms.
Masserdotti
Carlo
C
Laboratorio Biodiversity-Division Veterinaria, Brescia, Italy. veterinaria@biodiv.it
Bonfanti
Ugo
U
De Lorenzi
Davide
D
Ottolini
Nicola
N
D000818:Animals; D001391:Azo Compounds / Q000032:analysis*; D004396:Coloring Agents / Q000032:analysis; D004283:Dog Diseases / Q000175:diagnosis*; D004285:Dogs; D008080:Liposarcoma / Q000175:diagnosis / Q000662:veterinary*; D013194:Staining and Labeling / Q000379:methods*
D001391:Azo Compounds; D004396:Coloring Agents; C011049:oil red O