Fig. 4
From: Erdheim-Chester disease with bilateral orbital masses and multi-systemic symptoms: two case reports
A Gross resection specimen of the left orbit. The mass is solid and medium in texture; its section is grayish white and greyish yellow. B Histiocytic proliferative lesion, nodular/patchy nest conformation. Collagen fibers and fat vacuoles are in the background (hematoxylin–eosin, original magnification × 200). C Positive cytoplasmic CD68 immunostaining of tumor cells (CD68, original magnification × 400). D Positive cytoplasmic CD163 immunostaining of tumor cells (CD163, original magnification × 400). E Negative cytoplasmic S-100 immunostaining of tumor cells (S-100, original magnification × 400). F Ki67 immunostaining: 10–20% of tumor cells showed strong nuclear immunoreactivity (Ki67, original magnification × 400). G BRAF mutation detection: mutation in exon 15 was detected (V600E)