Survey Three 2001

Vulva

Supplied HGM-45
A section of vulval malignant melanoma shows the tumour cells which are spindle and their nuclei are pleomorphic and hyper chromatic with prominent nucleoli. Immunohistochemically, some of the tumour cells express melanoma marker HMB-45. It is a mouse monoclonal antibody raised against human melanosome. The antibody was found to react with a neuraminidase-sensitive oligosaccharide side chain of a glycoconjugate present in immature melanosomes. It gives positive signals with junctional and blue nevus cells, majority of melanomas, and tumours with melanoma / melanocytic differentiation. Generally epithelloid melanoma cells show more uniform staining than sarcomatous spindle-shaped melanoma cells. However negative results are found on intradermal nevi and normal adult melanocytes. Attention should be paid to the findings of positivity on breast and other epithelial tissues and tumours.

 

In-house HGM-45
A section from same tissue block is immunostained with in-house HMB-45. The average result is comparable with that stained with supplied antibody. The best results for both demonstrations are obtained by peroxidase blocking for 20 min., pressure cooking for 3 min., and immuno-stained with 1:50 (supplied) and 1:200 (in-house) diluted primary antibody for 30 min. at room temperature.

 

References:

Kapur RP, et al. Anti-melanoma monoclonal antibody HMB-45 identified an oncofetal glycoconjugate associated with immature melanosomes. J Histochem Cytochem 1992; 40(2):207.

Gown AM, et al. Monoclonal antibodies specific for melanocytic tumors distinguish subpopulations of melanocytes. Amer J Pathol 1986; 123:195.

Leong AS-Y, Millos J. An assessment of a melanoma-specific antibody (HMB-45) and other immunohistochemical markers of malignant melanoma in paraffin-embedded tissues. Surg Pathol 1989; 2:137.

Bonetti F, et al. Breast carcinoma positive for melanoma marker (HMB-45). HMB-45 immunoreactivity in normal and neoplastic breast. Amer J Clin Pathol 1989; 92:92.

 

Last updated on 25 November, 2001.

Prepared by HKIMLSQAP Anatomical Pathology Panel.

Copyright 2001 HKIMLSQAP. All Rights Reserved.