Lactating adenomas are a benign breast tumour that typically occur in the peri-partum period, and are one of the most prevalent breast lesions during puerperium 4.
Lactating adenomas commonly present as painless breast masses late in pregnancy or in the postpartum period. They are often palpable, mobile lesions that undergo rapid growth and may be large in size.
Lactating adenomas resolve or decrease in size in the postpartum period or with cessation of lactation but may recur during subsequent pregnancies.
They fall under adenomatous breast lesions. They are thought to occur in response to the physiological changes of pregnancy and during lactation and is likely due to rising oestrogen levels. Grossly, it is usually rubbery or firm and has a yellow to tan-colour with a lobulated cut surface. Histopathologically, a lactating adenoma is a well-circumscribed lesion composed of secretory lobules separated by delicate connective tissue.
There may be a predilection towards the anterior portion of the breast.
There are occasional reports of co-existing malignancy such as invasive ductal carcinoma 3,5.
Ultrasound is the initial imaging modality of choice especially considering the patient demographics.
Ultrasound features of a lactating adenoma can be variable 1. In general, the features are benign; however, some characteristics can mimic malignancy:
- most lactating adenomas have sharp margins
- most are homogeneous and hypoechoic/isoechoic
- may contain large cystic areas representative of infarction and necrosis
- most have posterior acoustic enhancement
- approximately a 20-33% of cases may show compressibility
Echogenic bands may be seen coursing through the mass, which correspond to fibrotic bands seen histologically.
May be seen as a well-defined lobulated breast mass and may have radiolucent central areas. They are sometimes seen as an asymmetrically increased density 8.
Treatment and prognosis
They are benign lesions and classically undergo spontaneous regression after pregnancy and lactation. However, a core biopsy is recommended for tissue sampling given their resemblance to other pathological entities.
Bromocriptine has been used to reduce the size of a lactating adenoma by suppressing prolactin secretion.
- development of a milk fistula following core biopsy
- they can cause development of foci of infarction of breast tissue 3
General imaging differential considerations include:
On ultrasound appearances there can be some imaging overlap with pregnancy associated breast cancer
- 1. Sumkin JH, Perrone AM, Harris KM et-al. Lactating adenoma: US features and literature review. Radiology. 1998;206 (1): 271-4. Radiology (abstract) - Pubmed citation
- 2. Baker TP, Lenert JT, Parker J et-al. Lactating adenoma: a diagnosis of exclusion. Breast J. 7 (5): 354-7. Breast J (link) - Pubmed citation
- 3. Sabate JM, Clotet M, Torrubia S et-al. Radiologic evaluation of breast disorders related to pregnancy and lactation. Radiographics. 2007;27 Suppl 1 : S101-24. doi:10.1148/rg.27si075505 - Pubmed citation
- 4. Magno S, Terribile D, Franceschini G et-al. Early onset lactating adenoma and the role of breast MRI: a case report. J Med Case Reports. 2009;3 : 43. doi:10.1186/1752-1947-3-43 - Free text at pubmed - Pubmed citation
- 5. Saglam A, Can B. Coexistence of lactating adenoma and invasive ductal adenocarcinoma of the breast in a pregnant woman. J. Clin. Pathol. 2005;58 (1): 87-9. doi:10.1136/jcp.2004.018275 - Free text at pubmed - Pubmed citation
- 6.Yang WT, Suen M, Metreweli C. Lactating adenoma of the breast: antepartum and postpartum sonographic and color Doppler imaging appearances with histopathologic correlation. J Ultrasound Med. 1997;16 (2): 145-7. J Ultrasound Med (citation) - Pubmed citation
- 7. Goto M, Yuen S, Nishimura T. MR imaging of tubular adenoma of breast associated with lactating change. Breast J. 15 (5): 536-7. doi:10.1111/j.1524-4741.2009.00774.x - Pubmed citation
- 8. Son EJ, Oh KK, Kim EK. Pregnancy-associated breast disease: radiologic features and diagnostic dilemmas. Yonsei Med. J. 2006;47 (1): 34-42. Yonsei Med. J. (link) - Free text at pubmed - Pubmed citation
- 9. Eurorad teaching files : Case 6455
- 10. Conant E, Brennecke C. Breast imaging. Mosby. ISBN:0323017460. Read it at Google Books - Find it at Amazon