Clinical diagnos
Case 305
【Progress】
Stereo-image guided tissue absorption biopsy revealed mucinous carcinoma. Two months later, she received partial mammectomy. Post-operative pathological examination revealed pure mucinous carcinoma. External radiation of 42.56 Gy was followed. Further, hormone therapy with Tamoxifen which is scheduled to given for 5 years, was initiated.
【Discussion】
Breast gland tissue composes of lobule (cluster of alveoli), duct (interlobular duct, extralobular duct) and stroma. Subcutaneous tissue composed of fibrous tissue and fat tissue surrounds breast gland tissue.
Breast cancer emerges from these tissues. Meanwhile, breast tissue is influenced under estrogen and progesterone. Estrogen induces growth of ducts and fat tissue, while progesterone induces growth of lobules and alveoli, leading swelling and pain. Further, human epithelial growth factor receptor 2 (HER2) influences the growth of breast tissue.
Breast carcinoma is also influenced by these hormones and then, categorized by presence of absence of these receptors into four types; estrogen receptor positive; progesterone positive; HER2 positive: triples negative (1, 2).
Meanwhile, breast cancer is categorized by classical histologic findings into twelve types: Ductal carcinoma in situ (DCIS), Lobular carcinoma in situ, Invasive ductal carcinoma, Invasive lobular carcinoma, Medullary carcinoma, Mucinous carcinoma, Metaplastic breast carcinoma, Mammary Paget carcinoma, Phyllodes tumors, Inflammatory carcinoma, Tubular carcinoma, and Papillary carcinoma (1, 3).
Mammography (MMG) is one of the four useful diagnostic modalities for detecting breast cancer: others are CT, MRI and ultrasound. However, there are forgotten areas for interpreting the presence of the tumor on diagnostic modalities, especially on MMG. Those include retro-subareolar space and retro-mammary gland space called Milkey way on a mediolateral oblique (MLO) view, while the medial half space of the breast and retro-mammary gland space between the posterior border of the breast parenchyma ad the chest wall (pectoralis major muscle) on a cranio-caudal (CC) view (4-7).
It is reported that post-mammary space is one of the critical pass-ways for tumor to infiltrate to axillary lymph nodes.
Breast imaging reporting and data base (BI-RADB) recommends a reporting document according to category; Category 1, negative; Category 2, benign (noncancerous finding); Category 3, probable benign; Category 4, Suspicious abnormality: Category 5, Highly suggestively of malignancy (cancer). Further, BI-RADS advocates category of breast condition; entirely fatty; scattered area of glandular tissue and fibrous connective tissue: heterogeneously dense: extremely dense (1).
In our case, her breast is categorized as heterogeneously dense and radiologic findings of a nodule with accumulation of minute calcs in her left breast are categorized Category 5 that was confirmed to be attributable breast cancer, mucinous adenocarcinoma by biopsy. The tumor was situated at one of the forgotten areas, retromammary gland space on CT and mammography.
【Summary】
We presented a fifty-year-old female with breast cancer of mucinous adenocarcinoma. Mammography and chest CT depicted a nodule with accumulation of minute calcs at post mammary gland space. It is borne in mind that there are unforgettable areas on mammography: post mammary gland area adjacent to pectoralis major muscle, retro-sub areolar area and inferior lateral area on MLO and CC views.
【References】
1.National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Breast Cancer. Available at https://www.nccn.org/professionals/physician_gls/pdf/breast.pdf. Version 3.2022 — May 7, 2022; Accessed: May 10, 2022.
2.Jorns JM, et al. Review of estrogen receptor, progesterone receptor, and her-2/neu immunohistochemistry impacts on treatment for a small subset of breast cancer patients transferring care to another institution. Arch Pathol Lab Med. 2013 Nov. 137(11):1660-3.
3.Dai D, et al. Competing Risk Analyses of Medullary Carcinoma of Breast in Comparison to Infiltrating Ductal Carcinoma. Sci Rep. 2020 Jan 17. 10 (1):560.
4.Nakano Y, et al. Importance of the retro-mammary space as a route of breast cancer metastasis. Breast Cancer. 2002;9(3):203-7.
5.Naylor SM, et al. A study to find the optimal orientation of the breast for the cranio caudal view, for screening purposes. Clin Radiol. 1999;54 (12): 804-6.
6.Brown M, et al. Geographical distribution of breast cancers on the mammogram: an interval cancer database. Br J Radiol. 2001;74 (880): 317-22.
7.Harvey J. Unusual Breast Cancers: Useful Clues to Expanding the Differential Diagnosis. Radiology. 2007;242(3):683-94.
2023.7.13