Medullary carcinoma of the breast
Medullary carcinoma of the breast is a rare and invasive subtype of breast cancer, characterized by distinct microscopic features including a well-defined boundary, immune system cells at its edges, and notably large, irregular cancer cells. This type of cancer accounts for less than 5 percent of all invasive breast cancer cases and typically manifests in women aged 45 to 54. Genetic predispositions, particularly mutations in tumor-suppressor genes like BRCA1 and TP53, play a significant role in its development, with family history and environmental factors, such as smoking, further increasing risk.
Symptoms may initially be absent, making regular screening crucial; however, as the disease progresses, patients may notice a firm lump in the breast, changes to the nipple, or skin dimpling. Diagnosis is achieved through imaging techniques and biopsies, while treatment often involves a combination of local therapies, like surgery and radiation, along with systemic approaches, including chemotherapy and targeted therapies. Despite being highly malignant, medullary carcinoma generally responds well to treatment, with a favorable prognosis when detected early, including a ten-year survival rate exceeding 90% for localized cases. Adopting a healthy lifestyle and regular screenings can be effective strategies for prevention.
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Subject Terms
Medullary carcinoma of the breast
ALSO KNOWN AS: MdBC, infiltrating breast cancer, invasive ductal carcinoma (IDC),
DEFINITION: Medullary carcinoma is a rare but invasive subgroup of breast cancers distinguished microscopically by a well-defined boundary, the presence of cells from the immune system at its edges, and large, misshapen cancer cells.
RELATED CONDITIONS: Familial breast cancer
Risk factors: Medullary breast carcinoma is more frequent in women with a genetic predisposition. Mutations in tumor-suppressor genes, whether genetic or unknown in origin, can prevent their normal function of suppressing abnormal growth. In women with a family history of reproductive-system cancers, smoking increases breast cancer risk significantly.
Estrogen can stimulate breast cancers. Changes in deoxyribonucleic acid (DNA), which carries the instructions for all cells, can cause normal cells to become cancerous, and such changes are more likely to occur with age.
Etiology and the disease process: Estrogen exposure tends to encourage breast cancer, and hormones can boost breast cancer growth. Gene mutations can inhibit the body’s defenses. The presence of germline mutations in the BRCA1 gene is associated with 7.8 and 19 percent of medullary carcinomas and 35 and 60 percent of breast cancers presenting with medullary features. TP53 gene mutations are also prevalent among medullary carcinomas.
Incidence: These infrequent cancers make up less than 5 percent of invasive breast cancer cases. The average age at diagnosis is between forty-five and fifty-four. Bilateral tumors are more common in individuals with a family history of medullary carcinoma, representing 3 to 18 percent of cases.
Symptoms: Most cancers start without symptoms, which are detectable by mammography or ultrasound. As the cancer develops, a lump or thickening may begin. An unusual lump in the breast or armpit area that feels firm, unlike other breast tissue, or seems “fixed” and immobile requires further investigation. Other symptoms include dimpling or puckering of the skin, breast pain, and changes to the nipple.
Screening and diagnosis: Medullary carcinomas are distinguishable by histology (microscopic examination). Monthly self-examination and regular mammography increase early detection. Diagnoses are accomplished using mammograms, ultrasounds, core biopsies, and magnetic resonance imaging. Staging for medullary carcinomas is as follows:
- Stage I: Cancerous cells have invaded nearby tissue.
- Stage II: Cancerous cells are in lymph nodes in the armpit.
- Stage III: Cancerous cells have invaded lymph nodes, breastbone, and other tissues above the waist.
Treatment and therapy: Treatment is usually a combination of local therapy (affecting only the cancer site, such as surgery and radiation) and systemic therapy using drugs (chemotherapy, hormone therapy, and immunotherapy), either by mouth or intravenously, to kill cancer cells that might have spread elsewhere but are not yet detectable. Targeted therapy to prevent cancer cell growth is also an option for some patients. If the tumor is larger than three centimeters or if it has metastasized to the lymph nodes, chemotherapy is typically indicated. With smaller tumors, surgery to remove cancerous tissue is usually followed by radiation.
Prognosis, prevention, and outcomes: Medullary carcinoma is highly malignant but responds well to treatment. When caught early, medullary breast cancers are curable, and the prognosis is good. The ten-year survival rate for individuals with localized tumors is over 90 percent, and for those with node metastasis, 74 percent. Balanced nutrition with avoidance of dietary fat and a healthy lifestyle that avoids smoking and includes exercise are among the best strategies for decreasing the chance of developing cancer.
Bibliography
Dabbs, David J. Breast Pathology. 3rd ed., Elsevier, 2024.
DePolo, Jamie. "Invasive Ductal Carcinoma (IDC)." Breastcancer, www.breastcancer.org/types/invasive-ductal-carcinoma. Accessed 20 June 2024.
Francescatti, Darius S., and Melvin J. Silverstein. Breast Cancer: A New Era in Managment. Springer, 2013.
Huober, J., et al. "Prognosis of Medullary Breast Cancer: Analysis of 13 International Breast Cancer Study Group (IBCSG) Trials." Annals of Oncology, vol. 23, no. 11, 2012, pp. 2843–851.
Limaiem, Faten, and Mouna Mlika. "Medullary Breast Carcinoma." National Library of Medicine, 1 Jan. 2023, www.ncbi.nlm.nih.gov/books/NBK542292. Accessed 20 June 2024.
Link, John, et al. The Breast Cancer Survival Manual: A Step-By-Step Guide for the Woman with Newly Diagnosed Breast Cancer. 7th ed. Holt, 2023.