Cutaneous BIM.
(A) This tumor has an overall polypoidal configuration with a biphasic pattern (H&E ×20).
(B) Positive nuclear BAP1 staining in small, peripheral melanocytes and epidermal keratinocytes (×100).
(C) Biphasic proliferation of melanocytes with large epithelioid cells (left) and smaller melanocytes with less cytoplasm (right) (H&E ×400).
(D) Absent BAP1 nuclear staining in large melanocytes (left) and retained nuclear BAP1 expression in small melanocytes (right) (×400).
(E, F, and G) Examples of variable cytologic atypia (H&E ×400, ×630, and ×400, respectively).
(H) BRAF V600E staining in both the small nevic population (top) and large epithelioid BAP1-deficient population (bottom) (×200).Do you want to add Medilib to your home screen?