Fig. 4.

Basal-like, predominantly non-apocrine invasive salivary duct carcinoma (SDC) with minor apocrine androgen receptor (AR) positive in situ component in a hyalinized nodule (HN). a Invasive SDC (left), capsule, and hyalinized nodule (right upper corner), H&E, 40x. b A 0.5 cm SDC in situ inside a HN. The upper one-third shows eosinophilic neoplastic cells with apical snouts, H&E, 400x. In the middle, immunohistochemical stain for p63 highlights basal cells, IHC, 400x. AR IHC is positive, lower one-third, IHC, 400x. c The entire invasive component was represented by solid proliferation of basophilic, AR-negative neoplastic cells with comedonecrosis, H&E, 200x. d A randomly distributed subset of neoplastic cells in the invasive component (left half) was highlighted by p63, IHC, 200x. Of note, compared to the basal/myoepithelial cells in the adjacent normal parotid tissue (right half), the p63-positive neoplastic cells (left) have larger and more irregular nuclei.

Modified from [4] with permission