PMC3806689_01
a Macroscopic appearance of the parotid tumor resected. b In the low-power view, the nodule was comprised of hyaline tissue with nests of tumor cells. c As cellular contents, high-grade carcinoma with a cribriform growth pattern and comedo-like necrosis (dotted line) and slit-like tubular epithelium with myoepithelium (arrows) were identified. d Histological diagnosis of resected lymph nodes was SDC with comedo-like necrosis.
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F1
Macroscopically, the tumor measured 25 x 17 mm at its largest dimensions and had a cartilage-like whitish cut surface with focal invasion of the surrounding fat tissue (fig. 1a). The mass consisted of broad hyaline tissue with nests of tumor cells (fig. 1b). At least two tissue components were identified: high-grade carcinoma with a cribriform growth pattern and comedo-like necrosis in the nests and slit-like tubular epithelium with myoepithelial cells at the base (fig. 1c). The recurrent tumor was histologically diagnosed as SDC (fig. 1d).
a Immunohistochemical analysis revealed that the tumor cells were positive for HER2 overexpression (Dako, Herceptest). b Dual-color chromogenic in situ hybridization revealed that HER2 gene was highly amplified, with HER2:chromosome 17 centromere ratio at 10:1 or more (Ventana, INFORM HER2 Dual ISH). Red = Chromosome 17 centromere; black = HER2.
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F2
The primary tumor was positive (score 3+) for membrane-localized HER2/neu protein (Dako, HerceptestTM) (fig. 2a). Dual-color chromogenic in situ hybridization revealed that HER2 gene was highly amplified (Ventana, INFORM HER2 Dual ISH) (fig. 2b).
a A thoracic CT scan revealed multiple bilateral pulmonary metastases (arrows). b After 4 cycles of chemotherapy with paclitaxel and trastuzumab, a CR of all pulmonary metastatic lesions was observed.
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F3
Five months later, CT revealed multiple bilateral pulmonary metastases (fig. 3a), and systemic treatment with paclitaxel (175 mg/m2) and trastuzumab (8 mg/kg dose loading followed by 6 mg/kg every 3 weeks) was initiated every 21 days. All pulmonary metastatic lesions had regressed after 4 treatment cycles (fig. 3b), and CR was confirmed after 7 cycles.