Solid papillary carcinoma of breast: a clinicopathologic study of 73 case / 临床与实验病理学杂志

ABSTRACT

Purpose To study the clinicopathologic features, immunophenotype and differential diagnosis of solid papillary carcinoma (SPC) of breast.Methods 73 cases of breast SPC with or without invasive carcinoma were collected, and the clinical data and histopathologic features were analyzed with further investigation of transmission electron microscopy and immunohistochemical staining (EnVision method). Selected antibodies included cytokeratin (CK), myoepithelial markers, neuroendocrine markers, proliferation marker Ki-67 and ER,PR,c-erbB-2,etc.Results All the patients were females with mean age of 64.7 years.The presenting symptoms were either a palpable breast mass or nipple discharge.Metastasis was observed in 43 cases who had undergone axillary lymph node dissection. Histologically, the tumor displayed a solid-papillary growth pattern, with mucin production demonstrated in 25 cases. Intraductal papilloma was not uncommon at the peripheral area of the tumor. The tumor cells were polygonal, oval, spindled or signet ring-like and contained abundant eosinophilic to granular cytoplasm and mildly to moderately pleomorphic nuclei. More than 5 mitotic figures/10 HPF were observed in 51 cases. 43 cases contained foci of invasive carcinoma which showed similar cytologic features as those of in-situ component. Immunohistochemical study showed that the tumor cells were negative for basal cell cytokeratin; positivity for smooth muscle actin-alpha and p63 were demonstrated in the myoepithelial layers of fibrovascular cores, as well as around the expanded ductolobular units.Most cases also showed cytoplasmic positivity for chromogranin A (89.0%), synaptophysin (86.3%) and neuron-specific enolase (95.9%).The proliferatiing index, as highlighted by Ki-67 imnunostaining, was 9.2%.The tumor mainly expressed estrogen receptor and progesterone receptor. The staining for c-erbB-2 oncoprotein was negative in the most cases. Neuroendocrine granules were seen under transmission electron microscope in the cytoplasm.Conclusions SPC represents a subgroup of low-grade ductal carcinoma in situ.SPC predilection in older women is associated with mucinous and neuroendocrine components. Follow-up data suggest that SPC has a good prognosis.