Overview of adenomyelomeningoepithelioma of the breast
A tumor consisting of both myoepithelial and epithelial cells proliferating at the same time is called a mammary glandular myoepithelial tumor. The two types of cells may have a tubular structure, similar to a typical adenoma, with epithelial cells in the inner layer and myoepithelial cells in the outer layer, but they are not evenly distributed. It is the same as the adenomyelinating epithelioma that occurs in salivary glands.
Adenomyoepithelioma (AME) is a rare tumor that occurs in the breast, most of which are benign with a tendency to recur and a few are malignant and can metastasize.
It occurs in elderly women (>50 years old) and a few in men.
Since myoepithelial cells of the breast normally exist between the epithelium and basement membrane of the ducts, tumor cells growing around the ducts are often regarded as sclerosing adenopathy, while those growing in a duct-like structure are treated as general ductal or ductal adenomas, and are therefore easily overlooked.
Pathology of adenomatous epithelioma of breast
Pathological macroscopic examination: the tumor is well defined with surrounding tissues and has a pseudo-envelope. It may be solid, cystic, or with coffee-colored fluid inside the cyst. The cut surface is grayish white, grayish red or grayish yellow, tough, brittle or fish-like.
Pathological microscopy: Microscopically, the periphery of the unevenly distributed glandular ducts is surrounded by markedly hyperplastic myoepithelium. The glandular ducts are round, oval, mostly small, and may have eosinophilic secretions in the lumen. The glandular epithelium is rectangular or low columnar in shape, with parietal pulp secretion, eosinophilic cytoplasm, small or absent nuclei, and no heterogeneity. Some of the glandular duct epithelium may be hyperplastic and papillary in shape. The myoepithelium was arranged in nests, sheets, cords and trabeculae, mostly transparent myoepithelial cells with polygonal shape, round nuclei, small nucleoli, transparent cytoplasm and PAS staining (+); some myoepithelial cells were spindle-shaped with slightly eosinophilic cytoplasm; some myoepithelial cells were polygonal with eosinophilic cytoplasm.
In malignant AME, there were abundant spindle-shaped or hyaline myoepithelial cells with obvious heterogeneity and markedly increased nuclear schizophrenia, >5/10 HPF and up to 20/10 HPF, with a large number of tumor necrosis inside. The tumor tissue grew into the surrounding adipose tissue in a striated infiltrative pattern; some of the interstitial stroma had obvious proliferation of spindle cells; some of the interstitial mucus degeneration was obvious, and the cell had proliferation of vascular plexus.
Electron microscopic examination: the luminal surface of the glandular ducts had microvilli, laterally connected by tight junctions, with scattered mitochondria and smooth endoplasmic reticulum in the cytoplasm. The polygonal and spindle-shaped myoepithelial cells are interspersed, with differentiated bridging granules, a variable number of swallowing vesicles in the cytoplasm, dense bodies of myogenic fibers, thick tension filaments wrapped around the nucleus in bundles, and myofilaments located in more peripheral areas, with basement membrane material surrounding the myoepithelium or appearing between them.
Immunohistochemistry: the antibodies of choice are SMA, MSA, S100, Vim, desmin, cytokeratin, ER and PR.
Pathological typing of adenomyoma of the breast
Spindle cell type: Spindle-shaped myoepithelial cells are mainly proliferating, forming a bundle structure, and the proliferating cell mass may compress the lumen.
Glandular duct type: This type is characterized by aggregated hyperplasia of myoepithelial cells and glandular epithelial cells around the ducts, resembling sclerosing papilloma, tubular and adenotubular adenoma. When the epithelial proliferation is significant, the ducts may be occluded by pressure. The tumor often has no obvious border, and the hyperplastic ducts often protrude into the surrounding normal breast tissue and mix with the surrounding breast tissue, so that the tumor cannot be completely removed during surgery, which becomes a cause of recurrence after excision. In some cases, the glandular epithelium has obvious mucous-like metaplasia.
Lobular type: The hyperplastic myoepithelial cells are solid and nest-like, the cell pulp is often clear or eosinophilic, some resemble plasma cells, and often surround the compressed glandular epithelial cells, the myoepithelial cells may have mild anomalies, and a little nuclear division is seen. The tumor is surrounded by a complete or incomplete thick fibrous envelope, which extends into the tumor, separating the tumor into nodular and lobular tissues.
Immunohistochemistry: normal myoepithelial cells were strongly positive for Actin, while tumor myoepithelial cells were positive for S100 and GFAP, especially for S100 in spindle-shaped myoepithelial cells.
Diagnosis of adenomyelinating epithelioma of the breast
1.Clinical manifestations.
Adenomyositic epithelial tumor of the breast is mostly seen in women, but there are occasional reports of male cases, and the age of onset can be around 27-80. Most patients present with a single painless mass in the breast, which can be located in any area of the breast, and a few patients have nipple discharge.
The average diameter of the mass varies and the duration of the disease is nonspecific, with the longest being several years. Adenosarcoma of the breast usually presents as a solitary, solid nodular mass with borders, and in a few cases the masses have poorly defined borders.
2. Differential diagnosis of cancer.
(1) myoepithelial-rich carcinoma.
(2) myoepithelial carcinoma.
(3) septic carcinoma.
(4) adenomyelinating epithelial adenopathy.
(5) intraductal papillary tumor.
(6) clear cell tumor;
(7) Myofibroblastoma of the breast;
(8) Smooth muscle tumor of the breast
3, malignant adenomyeloblastoma of the breast: the differential diagnosis between benign and malignant is difficult, except for the presence of metastatic foci in the tumor, which can be referred to.
(1) Significantly increased nuclear schizophrenia, >5/10HPF;
(2) Abundant cells with obvious heterogeneity;
(3) The tumor shows infiltrative growth and satellite foci;
(4) Necrosis was present in the tumor;
(5) NA polyploidy analysis was aneuploidy.
Treatment of adenosarcoma of the breast
The principle of surgical treatment: for benign tumors, local excision of the tumor is the treatment of choice.
Occasionally, recurrence and carcinoma may occur after local excision, mostly within 5 to 6 years after surgery. Recurrence is common in glandular duct type, because this type of tumor and surrounding tissues often lack clear boundaries, so that the tumor is not easy to be excised completely, resulting in the possibility of local recurrence of tumor after surgery. If the tumor recurs, the corresponding local excision can be performed again, and further judgment can be made according to the pathological results, and if cancer is confirmed, the corresponding radical surgery can be performed.
Prognosis and treatment
Adenosarcoma of the breast is a benign tumor, but it is prone to recurrence if the resection is not complete, and recurrence is related to the following factors.
The tumor cells are pleomorphic, increased nuclear schizophrenia, necrosis in the tumor, tumor infiltration of surrounding tissues, glandular epithelial papillomatous hyperplasia or myoepithelial hyperplasia in the tumor surrounding tissues, and coexistence of mammary adenomyeloneuroepithelioma with other malignant tumors.
The tumor may become malignant after multiple recurrences, such as invasive ductal carcinoma, myoepithelial carcinoma, malignant adenomyeloblastic tumor or with osteosarcoma and undifferentiated carcinoma components, etc., which need to be followed up closely.