Benign Breast Lesions

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SLIDES

• Slide 1: Normal histology of breast tissue consists of the lobules. Within the lobules are small acini. Lobules are connected to intralobular ductules and interlobular ducts. Lobules are surrounded by loose connective tissue sensitive to sex hormones.
• Slide 2: The ducts are lined by an inner layer of secretory cells and an outer layer of myoepithelial cells.
• Slide 3: Immunohistochemical stain for smooth muscle actin identifies myoepithelial cells with brownish deposits in the cytoplasm.
• Slide 4: Fibrocystic change. Small cysts are surrounded by fibrous stroma.
• Slide 5: Fibrocystic change. Large cysts contain brown black fluid.
• Slide 6: Fibrocystic change. Multiple dilated cystic spaces with occasional papillary projections.
• Slide 7: Fibrocystic change. The ducts are lined by apocrine metaplastic cells with focal papillary proliferation.
• Slide 8: Apocrine metaplastic cells are characterized by having abundant eosinophilic granular cytoplasm and accumulation of secretory granules in the apical cytoplalsm, so called apocrine snout. Some nuclei contain nucleoli.
• Slide 9: Apocrine metaplastic cells undergo papillary proliferation. Nuclear enlargement and prominent nucleoli are common.
• Slide 10: Ductal hyperplasia. Proliferating cells form solid sheets (center field), irregular glandular spaces and papillary projections.
• Slide 11: Ductal hyperplasia. Proliferating cells form sieve-like spaces, so called cribriform pattern.
• Slide 12: Ductal hyperplasia without nuclear atypia. The proliferating cells consists of secretory cells with round to oval nuclei. Myoepithelial cells have oval to elongated, slightly hyperchromatic nuclei.
• Slide 13: Atypical ductal hyperplasia. The proliferating cells form irregular glandular spaces.
• Slide 14: Atypical ductal hyperplasia. Higher magnification of Slide 13 to demonstrate atypical cells with enlarged, irregular, hyperchromatic nuclei, uneven distribution of chromatin, and medium sized nucleoli. Individually, these atypical cells have the characters of malignant cells. However, the background benign epithelial cells and myoepithelial cells remain.
• Slide 15: Atypical ductal hyperplasia with solid filling of a duct.
• Slide 16: Atypical ductal hyperplasia. Higher magnification of Slide 15. Within this focus, highly atypical cells have become quite homogeneous, however, rare myoepithelial cells with small, dark nuclei remain.
• Slide 17: Atypical lobular hyperplasia. The lobules are expanded by atypical cells with round to oval nuclei and small nucleoli. In the background, occasional epithelial cells and myoepithelial persist.
• Slide 18: Atypical lobular hyperplasia. The distended lobules are occupied by atypical lobular cells with round to oval nuclei and small nucleoli. Rare myoepithelial cells with small dark nuclei remain.
• Slide 19: Adenosis. In the early stage, the lobules are enlarged.
• Slide 20: Adenosis. Higher magnification of Slide 19 to demonstrate small acini to consist of epithelial cells and myoepithelial cells (vacuolated cytoplasm and small dark nuclei).
• Slide 21: Sclerosing adenosis. The enlarged lobule undergoes fibrosis. Multiple microcalcifications present as purple round bodies.
• Slide 22: Sclerosing adenosis. Higher magnification of Slide 21 to demonstrate proliferation of myoepithelial cells and stromal fibrosis. Microcalcifications have a laminated, purple appearance.
• Slide 23: Sclerosing adenosis, late stage. Acini begin to decrease in number.
• Slide 24: Sclerosing adenosis, late stage. Atrophic acini are surrounded by abundant fibrous stroma.
• Slide 25: Microglandular adenosis. Small, regular glandular profiles occur within adipose tissue. Dilated ducts in the periphery contain microcalcifications.
• Slide 26: Microglandular adenosis. These glands maintain regular, smooth, round configuration and are surrounded by delicate fibrous tissue. In the case of invasive tubular carcinoma, the neoplastic glands are more irregular in shape and in direct contact with adipocytes.
• Slide 27: Fibrosis. Broad areas of hypocellular fibrous tissue contain clusters of dilated ducts. Most of the lobules have disappeared.
• Slide 28: Mammary duct ectasia. The dilated duct contains foamy histiocytes and the periductal tissue is infiltrated by lymphocytes.
• Slide 29: Mammary duct ectasia. In this late stage, the ductal lumen is filled with lipid material and foamy histiocytes. The periductal fibrosis is marked with collections of hemosiderin laden macrophages.
• Slide 30: Intraductal papilloma. Small, well-circumscribed polypoid nodules occur in a dilated duct.
• Slide 31: Intraductal papilloma. Multiple papillomatous nodules and stromal fibrosis (lower center field).
• Slide 32: Intraductal papilloma. Papillary proliferation with irregular glandular spaces.
• Slide 33: Intraductal papilloma. Solid area consisting of both epithelial and myoepithelial cells.
• Slide 34: Intraductal papilloma with stromal fibrosis simulating invasive carcinoma.
• Slide 35: Radial scar. Fibrosis begins to occur in the center of ductal hyperplasia causing a radiating patter of the ducts.
• Slide 36: Radial scar. Marked fibrosis and elastosis occur in the ductal hyperplasia.
• Slide 37: Fibroadenoma with homogeneous fibrous stroma and cleft-like spaces.
• Slide 38: Multiple fibroadenomas with smooth, circumscribed borders.
• Slide 39: Fibroadenoma, intercanalicular type with branching and budding ducts surrounded by edematous fibrous stroma. Note smooth borders.
• Slide 40: Fibroadenoma, intracanalicular type with ducts compressed by polypoid fibrous stroma with mild cellularity.
• Slide 41: Fibroadenoma with coexisting papillary carcinoma. This fibroadenoma has acellular fibrous stroma and inactive ducts to indicate long standing disease with involution. In contract, the papillary carcinoma form complex papillary projections.
• Slide 42: Higher magnification of papillary carcinoma to demonstrate nuclear atypia and increased mitotic activity.
• Slide 43: Phyllodes tumor. Multiple, polypoid nodules are separated by cleft-like spaces.
• Slide 44: Phyllodes tumor. Pre-existing old fibroadenoma (right field) has acellular fibrous stroma and atrophic ducts. In contrast, the phyllodes tumor contains hyperplastic ducts and cellular stroma (left field).
• Slide 45: Phyllodes tumor. A hyperplastic duct is surrounded by fibrous stroma with low and high cellularity.
• Slide 46: Phyllodes tumor. In the fibrosarcomatous stroma, the tumor cells have elongated, hyperchromatic nuclei undergoing active mitosis.
• Slide 47: Phyllodes tumor with irregular infiltrative borders extending into adipose tissue.
• Slide 48: Hamartoma of breast consisting of dilated ducts and fibrous stroma. A partial capsule is evident in the lower field.
• Slide 49: The fibrous stroma in this hamartoma has slit-like spaces without endothelial cells, so called pseudoangioma.
• Slide 50: Capillary hemangioma consists of lobules of capillaries of varying sizes.
• Slide 51: Angiosarcoma, well-differentiated. Irregular vascular spaces infiltrate the fibrous stroma.
• Slide 52: Higher magnification of Slide 51 to demonstrate the malignant cells with nuclear enlargement, hyperchromasia and irregularity.
• Slide 53: Angiosarcoma, poorly differentiated. Malignant cells form irregular spaces simulating glandular neoplasm. Without immunohistochemical stains for endothelial cell marker, a correct diagnosis may not be make.
• Slide 54: Granular cell tumor with firm consistency and irregular borders strongly suggests carcinoma.
• Slide 55: Granular cell tumor. Tumor cells form clusters and proliferate between collagen bundles.
• Slide 56: Granular cell tumor. Tumor cells have abundant eosinophilic, granular cytoplasm simulating infiltrating ductal carcinoma with apocrine metaplasia.
• Slide 57: Liposarcoma, well-differentiated, consists of lipomatous differentiation in the right field and fibrous area in the left with atypical cells.
• Slide 58: Liposarcoma showing signet ring lipoblast in the center field. The stroma is vascular and myxoid.
• Slide 59: Chondrosarcoma with chondroid matrix in the right lower field.
• Slide 60: Chondrosarcoma with highly atypical tumor cells surrounded by lacunar spaces and myxoid stroma.
• Slide 61: Paget's disease of nipple. Paget's cells have pale, vacuolated cytoplasm and large nuclei and migrate through the epidermis from parabasal cell layers upward. Notice the highest concentration in the deep layers of epidermis.
• Slide 62: Paget's disease of nipple. Hyperkeratosis of epidermis and chronic inflammation in the dermis are common. Paget's cells permeate through the epidermis.
• Slide 63: Paget's disease of nipple. Comedo ductal carcinoma in situ with central necrosis involves the lactiferous duct.
• Slide 64: Nipple adenoma with papillary projections and solid sheets of tumor cells.
• Slide 65: Nipple adenoma. Higher magnification to demonstrate proliferation of both epithelial and myoepithelial cells.
• Slide 66: Chronic dermatitis of nipple skin. Hyperkeratosis and hyperplasia of epidermis with plump rete pegs. A band of lymphocytes and plasma cells occurs just beneath the skin
• Slide 67: Fat necrosis. Irregular fatty spaces are surrounded by foamy histiocytes and multinucleated giant cells.
• Slide 68: Fat necrosis in late stage consisting of abundant foamy macrophages (left upper corner) and fibrosis.