P75 nerve growth factor receptor staining is superior to S100 in identifying spindle cell and desmoplastic melanoma.
BACKGROUND
Spindle cell melanoma (SCM) including desmoplastic melanoma (DM) is a rare variant of malignant melanoma that may present diagnostic difficulties particularly when staining with S100 is negative, weak, focal, or a combination of these. Conventional melanocytic markers in SCM are usually negative.


OBJECTIVE
We sought to compare the staining of p75 nerve growth factor receptor (NGF-R) and S100 in SCMs.


METHODS
We evaluated the staining of p75 NGF-R and S100 in 13 cases of SCMs: 3 SCMs without desmoplasia, 5 pure DMs, and 5 combined DMs with a conventional component.


RESULTS
Staining with p75 NGF-R was positive in 13 of 13 (100%) cases of SCMs. In 3 cases the intensity of staining and the percentage of cells staining with this marker were greater than those with S100. One case of SCM was negative for S100 but demonstrated strong expression of p75 NGF-R. One case was focally and weakly positive with S100 but expressed strong positive staining with p75 NGF-R. Absence of staining with p75 NGF-R was noted in the conventional round cell component of two of 5 (40%) combined DMs whereas the same areas were strongly positive for human melanoma black (HMB)-45 and Melan-A. In 5 of 5 (100%) cases of combined DMs the desmoplastic component stained positive with p75 NGF-R, demonstrating an inverse relationship with the staining of conventional melanocytic markers.


CONCLUSIONS
Small study size was a limitation.


CONCLUSIONS
p75 NGF-R exhibits superior staining characteristics and greater sensitivity in identifying SCM and DMs than S100. P75 NGF-R may be a useful diagnostic and ancillary stain in addition to S100.
Lazova
Rossitza
R
Department of Dermatology, Yale University School of Medicine, New Haven, Connecticut 06520-8059, USA. rossitza.lazova@yale.edu
Tantcheva-Poor
Iliana
I
Sigal
Alicia C
AC
D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002277:Carcinoma / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000592:standards; D008297:Male; D008545:Melanoma / Q000378:metabolism* / Q000473:pathology; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D017475:Receptors, Nerve Growth Factor / Q000378:metabolism*; D015203:Reproducibility of Results; D009418:S100 Proteins / Q000378:metabolism*; D012680:Sensitivity and Specificity; D012878:Skin Neoplasms / Q000378:metabolism* / Q000473:pathology; D013194:Staining and Labeling / Q000592:standards
D014408:Biomarkers, Tumor; C484065:NGFR protein, human; D009419:Nerve Tissue Proteins; D017475:Receptors, Nerve Growth Factor; D009418:S100 Proteins