PMC8140801_01
(A) Histopathologic findings on hematoxylin and eosin (H&E) staining of the salivary ductal carcinoma case at diagnosis (5x). (B) H&E staining of the salivary ductal carcinoma case at diagnosis (20x). (C) Immunohistochemistry (IHC) analysis for human epidermal growth factor receptor 2 (HER2)-overexpression showing HER2-positive score 3+ complete membranous in more than 10% tumor at diagnosis (5x). (D) IHC analysis for HER2-overexpression showing HER2-positive tumor cells (20x). (E) Nuclear staining of androgen receptor (AR) showing strong positive AR expression in all tumor cells at diagnosis (5x). (F) Nuclear staining of AR showing strong positive AR expression in all tumor cells at diagnosis (20x).
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fig1
Biopsy of the right parotid mass showed human epidermal growth factor receptor 2 (HER2)-positive, AR-positive SDC by immunohistochemistry (Figs 1A-1F). Since immunohistochemistry showed high expression of AR (Fig 1C), the patient was started on tab alpelisib 300 mg and tab bicalutamide 50 mg orally daily to target the PIK3CA and AR pathways, respectively.
Current and previous positron emission tomography-computed tomography scans demonstrating response to treatment from PIK3CA and androgen receptor inhibitors. (A) Arrows show near-complete metabolic resolution of the primary lesion when compared with prior scans. (B) Arrows show complete metabolic resolution of the vertebral metastasis when compared with prior scans. (C) Arrows show complete metabolic resolution of the lung and vertebral metastasis when compared with prior scans. (D) Arrows show near-complete metabolic resolution of the primary lesion when compared with prior scans.
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fig2
Figures 2A-2C compare recent PET-CT reports with the ones done 8 months before.
Depiction of treatment regimen and timeline of the patient with salivary duct carcinoma. AR, androgen receptor; HER2, human epidermal growth factor receptor 2; IHC, immunohistochemistry; PET-CT, positron emission tomography-computed tomography.
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fig3
The data analysis revealed genomic alterations (Table 1) including PIK3CA mutation (Fig 3A), which was considered targetable. A timeline overview of the patient's management is summarized in Figure 3.