Table 3.
Expected immunohistochemical expression patterns of neoplastic histiocytic disorders in the dog
| Markers | LCs | Interstitial DC | CCH | HS | MFH |
|---|---|---|---|---|---|
| CD1 (a,b,c) | + | + | + | + | − |
| CD11 b | − | − | − | − | +/− |
| CD11 c | + | + | + | + | +/− |
| CD11 d | − | − | − | − | − |
| CD18 | + | + | + | + | +a |
| CD4 | − | + | − | − | − |
| (if activated) | |||||
| MHC II | + | + | + | + | Unknown |
| E-cadherin | + | − | + | − | − |
| Thy-1 | − | + | − | − | − |
| Vimentin | n/a | n/a | n/a | + | + |
| SM Actin | n/a | n/a | n/a | +/− | +/−b |
LCs — Langerhans’ cells; MFH — malignant fibrous histiocytoma; CCH — canine cutaneous histiocytoma; HS–histiocytic sarcoma (localized or disseminated)
a
Some scattered CD18 positive cells are often seen in staining of MFH due to the infiltration of monocytes and macrophages into the tumor
b
In one large study, the smooth muscle actin staining was of stromal cells or vascular smooth muscle, not the actual tumor cells (26)
In macrophage disorders or malignancies, CD11b or CD11d expression is usually identified rather than CD11c