1
Geyer et al.
Supplementary Figure Legends
Supplementary Figure 1: Histological and immunohistochemical features of case 1. Low power magnification of case 1 (a and b) showing infiltrative borders, with neoplastic cells and accompanying stroma infiltrating and encasing normal breast tissue (* , b). Nothe the conspicuous lymphocytic infiltrate at the periphery of the tumour. Immunohistochemical staining with antibody against cytokeratin 17 (c) highlights the epithelial component of this tumour, which displayed strong and diffuse positivity. Epithelial cells were embedded in a spindle cell stroma and frequently seemed to blend with the spindle cells (d and e). Medium power magnification of cytokeratin 17 staining shows that some of the spindle stromal cells (arrows, f, 200X magnification) also express this epithelial marker. Epithelial cells were predominantly arranged in tubules or clusters (g) and displayed low grade nuclear pleomorphism (h) and focal squamous differentiation (I).
Supplementary Figure 2: Histological and immunohistochemical features of case 3. Low power magnification of case 3 (a and b) showing infiltrative borders, with infiltration of fat tissue and central sclerotic areas. Immunohistochemical staining with antibodies against cytokeratin 14 (c) highlights the epithelial component of this tumour, which displayed strong and diffuse positivity. The stromal component was characterised by a cellular, bland, fibromatosis-like stroma (d). Sclerotic areas in the centre of the lesion correspond to normal entrapped ducts (e). Medium power magnification of cytokeratin 14 staining shows that some of the spindle stromal cells (arrows, f) also express this epithelial marker. Epithelial cells were arranged in tubules or cell clusters (g) and displayed low grade nuclear pleomorphism (h) and focal squamous differentiation (I).
Supplementary Figure 3: Histological and immunohistochemical features of case 4.Low power magnification of case 4 (a and b) showing infiltrative borders, with infiltration of fat tissue and mild to moderate lymphocytic infiltrate at the periphery. Immunohistochemical staining with antibodies against cytokeratin 5/6 (c) highlights the epithelial component of this tumour, which displayed strong and diffuse positivity. Epithelial elements displayed syringoma-like features and a appeared to merge with the spindle cells (d and e), which displayed focal positivity for cytokeratin 5/6 (arrows, f). Long extensions of a relatively cellular and bland stroma were present at the periphery of the tumour with entrapment of normal ducts (g). Epithelial cells displayed low grade nuclear pleomorphism, with tubular formation (h) and focal squamous differentiation (i).
Supplementary Figure 4: Histological and immunohistochemical features of case 5.Low power magnification of case 5 (a and b) showing infiltrative borders, a central sclerosing lesion with a papillary component (a, top left corner) and conspicuous lymphocytic infiltrate at the periphery of the tumour. Immunohistochemical staining with antibodies against cytokeratin 14 (c) highlights the epithelial component of this tumour, which displayed strong and diffuse positivity. Epithelial elements were often arranged in tubules with open lumina (d). Infiltration of normal breast tissue (*, e) was observed. Stromal spindle cells displayed focal posititivity for cytokeratin 14 (arrows, f) and in some areas epithelial cell clusters were surrounded by and merged with the stromal cells (g). Low grade nuclear pleomorphism (h) and focal squamous differentiation (i) were identified.
Supplementary Figure 5: Histological and immunohistochemical features and chromogenic insitu hybridisation with a probe for the Epidermal Growth Factor Receptor (EGFR) gene of case 2. Low power magnification of case 5 (a) which displayed a component with low grade features (b, e, h, k, n, q, t) typical of low-grade adenosquamous carcinoma, including small tubules and cell clusters with syringoma-like features, surrounded by a relatively cellular bland stroma (b), merging of spindle and epithelial cells and focal squamous differentiation (h). Progression to high grade adenosquamous carcinoma (c, f, i, l o, r and u) and an overtly malignant sarcomatous component (d, g, j, m, p, s and v) was observed. Immunohistochemistry with antibodies against cytokeratin 14 is shown in (n to p); immunohistochemistry with antibodies against epidermal growth factor receptor is shown in (n to p); chromogenic in situ hybridisation with probes for EGFR is shown in (q to v). Please note that some of the spindle cells in the low and high grade adenosquamous components expressed cytokeratin 14 (arrows, k and l) and displayedEGFR gene clusters (arrows, q, r, t and u).