Table 1.
Comparative data for BRAF status evaluation in primary and metastastics sites.
Table 2.
BRAF status according to histological subtype of the primary melanoma site.
Figure 1.
VE1 immunostaining for BRAF p.V600E in positive, negative and ambiguous cases.
A. Positive case showing diffuse dark brown cytoplasmic immunostaining. Immunoperoxidase staining ×50, magnification. B. Metastatic lymph node showing positive staining with homogeneity between tumor areas. Note the presence of melanophages with gray-green cytoplasmic dots (asterisks) in sinuses. Immunoperoxidase staining ×10, magnification. C. Primary cutaneous sample of a case without BRAF mutation. Note the absence of staining of tumor cells and the presence of gray-green pigment in melanophages. Immunoperoxidase staining, ×250 magnification. D. Ambiguous staining in a primary melanoma without BRAF p.V600E mutation as detected by molecular techniques. Presence of a faint staining of tumor cells (arrows) contrasting with the intense pigmentation of melanophages (asterisks). In such cases (3 in our study) it was not possible to assess whether tumor cells were immunostained or pigmented. Immunoperoxidase staining, ×400 magnification. E. Negative immunostaining case for BRAF p.V600E in a primary melanoma showing artifacts with diffuse and nuclear small brown dots differing from the cytoplasmic staining of the positive cases. Immunoperoxidase staining, ×400 magnification. F. Metastatic lymph node with positive brown cytoplasmic staining of tumor cells and gray-green pigmentation of melanophages. Immunoperoxidase staining ×400 magnification. G. Metastatic lymph node involved by melanoma. Extensive necrosis with peripheral tumor areas. Hematein-eosin staining, ×10 magnification. H. Same sample than in E. Adjacent section immunostained with the VE1 antibody showing positive tumor area (arrow) while necrosis remains negative (asterisks). Immunoperoxidase staining ×10 magnification.