The cells showed a positive reaction for HMB-45
antigen [Figure 1]b.
400x magnified images are given in Figure 2, 3, 4 with the actin, HMB-45
and haematoxylin and eosin staining of the mass.
The tumor showed positive staining for Desmin (Figure 3), and negative for HMB-45
The effect of mitotic index, pigmentation, S100, HMB-45
, Melan-A and C-KIT on survival were evaluated.
Immunohistochemistry was performed with markers like keratin, vimentin and HMB-45
to know the histogenesis of tumour.
Additional immunostains performed at our institution revealed negative staining of the lesional cells for wide spectrum cytokeratin (CK), CK OSCAR (Figure 5A), epithelial membrane antigen (EMA), S100, HMB-45
, smooth muscle actin and positive staining for CD34, desmin (Figure 5 B), estrogen receptor (Figure 6), and BCL-2.
13-16,18-20,22-27) The melanocytic marker HMB-45
is expressed in all cases, and Melan-A is positive in up to 80% of tumors.
7,8) Markers associated with malignant melanoma include S-100 protein, gp 100, MART-1, tyrosinase, NK1/ C3, vimentin, HMB-45
, and KBA.
Some ONB can show focal melanin pigment and rare positivity for HMB-45
but positivity for neuroendocrine markers, negativity for Melan-A and careful interpretation of Masson Fontana rules out sinonasal melanoma.
4) The smooth muscle component of AML (and other PEComas) stains positive not only for actin and desmin but also for melanocytic markers such as HMB-45
In a number of studies, the Melan-A marker was shown to be more specific and sensitive than the S-100 and HMB-45
melanocytic markers (14, 20, 22-24).
Histological examination of a renal leiomyoma reveals fusiform to spindle shaped cells with positive immunohistochemical staining for smooth muscle markers (desmin, caldesmon, and SMA) and negative staining for HMB-45
and cathepsin K.