Challenges in diagnosing canine spindle cell tumours using immunohistochemistry, illustrated by three nonpigmented malignant cases from the nictitating membrane

Table 3 Immunohistochemistry results and diagnoses

Immunohistochemistry	Case 1	Case 2	Case 3
Vimentin	+	++	+
S-100	+	80% ++	+
SMA	N/A	50% ++	+
Cytokeratin	-	-	-
GFAP	N/A	+	++
Melan-A (human protocol)	-	-	-
First diagnosis	Hemangiosarcoma	Sarcoma	Sarcoma
Melan-A (dog-adapted protocol)	N/A	30% +	< 10% +
PLN2	N/A	20% +	50% ++
Final diagnosis	Hemangiosarcoma	Lightly pigmented melanoma	Very lightly pigmented melanoma

Immunohistochemistry results and diagnoses of the canine membrana nictitans tumours by the human protocol and the dog-adapted protocol used in the current study. +: slightly positive (when estimated with a percentage this is noted), ++: strongly positive (with a percentage when noted), -: negative, N/A: not available

ISSN: 1751-0147