Histology of DCIS and LCIS

The pathology report will include several significant terms in determining the possibility of recurrence and progression to invasive cancer, thus providing the basis for the type of treatment that should be used for DCIS and LCIS.

Non-cancerous changes were seen under the microscope that will not influence the prognosis

Breast changes that can indicate DCIS can return after treatment are as follows:

Cribriform – rare type – slow proliferation and low grade

Micropapillary – extensive involvement in the ducts – high risk for recurrence (Castellano et al., 2010)

Apocrine – not well defined in DCIS; relatively rare (D'Arcy & Quinn, 2019)

Comedo – aggressive lesions; high-grade DCIS (Pacifici & Rasuli, 2020)

Comedonecrosis – remnants of cells that have died; high-grade subtype of DCIS; most aggressive type

A papillary – fern-like pattern within the duct;

Solid – a solid pattern of cells that have filled the duct; High-grade DCIS

The above is used to describe how the DCIS looks under the microscope and is graded by chances of recurrence:

• DCIS that is high grade is nuclear grade 3, or has a high mitotic rate is more likely to come back (recur) after it is removed with surgery. 
  
• DCIS that is intermediate grade is nuclear grade 2 or has an intermediate mitotic rate falls in between these two.
  
• DCIS that is low grade is nuclear grade 1 or has a low mitotic rate is less likely to come back after surgery.

Additional treatment and more follow-up can be prescribed for patients with higher-grade DCIS.

Estrogen and progesterone receptors

According to the American Cancer Society, normal breast cells and some breast cancer cells have receptors that attach to estrogen and progesterone and need these hormones for the cells to proliferate. https://www.cancer.org/cancer/breast-cancer/understanding-a-breast-cancer-diagnosis/breast-cancer-hormone-receptor-status.html
Breast cancer cells may have one, both, or none of these receptors.

• ER-positive breast cancers with estrogen receptors are called ER-positive (or ER+) cancers.
  
• PR-positive: Breast cancers with progesterone receptors are called PR-positive (or PR+) cancers.
  
• Hormone receptor-positive: If the cancer cell has one or both of the receptors above, the term hormone-receptive positive (also called hormone-positive or HR+) breast cancer may be used.
  
• Hormone receptor-negative: If the cancer cell does not have the estrogen or the progesterone receptor, it's called hormone-receptor negative (also called hormone-negative or H.R.-).

Keeping the hormones estrogen and progesterone from attaching to the receptors can help keep cancer cells from proliferating and metastizing. Some drugs, such as tamoxifen, can be used to do this.

Some cases of DCIS contain estrogen receptor and progesterone receptor-positive hormone receptors on their surfaces, but some are negative. Tamoxifen is the medication traditionally used to treat these hormone receptors positive DCIS. However, patients with estrogen and progesterone receptor-negative DCIS will not need Tamoxifen or other hormone-blocking drugs. https://breast360.org/topic/2016/09/30/ductal-carcinoma-in-situ-overview/

Types of cells associated with Lobular Carcinoma in situ (LCIS)
Compared with women without LCIS or DCIS, women with LCIS have a 7 to 12 times higher risk of developing invasive cancer in either breast. The history and optimal treatment of PLCIS and FLCIS types are still being investigated. These are generally accepted descriptions of the different kinds of LCIS:

• Classic LCIS: The cells lining the breast's lobules are smaller and are about the same size.
  
• Pleomorphic LCIS: The endothelial cells lining the breast's lobules are larger and look more abnormal.
  
• Florid LCIS: The cells lining the lobules have replicated enough to form a mass, typically with an area of dead cells in the middle (called central necrosis).
  https://www.cancer.org/cancer/breast-cancer/non-cancerous-breast-conditions/lobular-carcinoma-in-situ.html

Pleomorphic cells called PLCIS occur in 2.7 to 4.4% of lobular neoplasia. They occur more frequently in the following situations:

• More common in postmenopausal women
  
• Tend to be older than classic LCIS
  
• The average age reported is 52 - 55 years
  
• In a study of 24 cases, ages were 36 - 86 years
  (Ann Surg Oncol 2015;22:4263, Histopathology 2014;64:981)

Prognostic factors

• PLCIS may be frequently associated with invasive disease and has a more aggressive course
  
• PLCIS is considered to be a precursor of invasive cancer in addition to a marker of increased risk
  
• PLCIS is frequently multifocal and extensive, and positive/close margins are typical in the setting of breast-conserving surgery
  
• Cases with isolated PLCIS are less likely / rarely recur compared to those associated with invasive carcinoma
  https://www.pathologyoutlines.com/topic/breastmalignantpleolcis.html

Florid (FLCIS) is relatively rare. In a study by Bagaria et al. (2011) of 210 women with LCIS, 81% had nonflorid type, with 39% having F-LCIS. The florid LCIS had the following patterns:

• Discreet foci
  
• An invasive component
  
• Considered to be a precursor for invasive lobular carcinoma

References:

Bagaria SP, Shamonki J, Kinnaird M, Ray PS, Giuliano AE. (2011). The florid subtype of lobular carcinoma in situ: marker or precursor for invasive lobular carcinoma? Ann Surg Oncol. 18(7), 1845-51.

Castellano, I., Marchiò, C., Tomatis, M. et al. (2010). Micropapillary ductal carcinoma in situ of the breast: an inter-institutional study. Mod Pathol 23, 260–269.

D'Arcy, C. & Quinn, C. (2019). Apocrine lesions of the breast: part 1 of a two-part review: benign, atypical and in situ apocrine proliferations of the breast Journal of Clinical Pathology.72, 1-6.

Pacifici, S., Rasuli, B. (2020). Comedo type ductal carcinoma in situ. Reference article,

Radiopaedia.org. (accessed on April 28 2022) https://doi.org/10.53347/rID-15335

Srivastava, S. (2022). LCIS pleomorphic. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/breastmalignantpleolcis.html. Accessed April 28, 2022.