Evaluating agreement, histological features, and relevance of separating pleomorphic and florid lobular carcinoma in situ subtypes

Immediate and delayed risk of breast cancer associated with classic lobular carcinoma in situ and its variants

OBJECTIVE

To determine the risk of breast cancer due to lobular carcinoma in situ (LCIS).

METHODS

This retrospective IRB-approved study identified cases of LCIS after percutaneous breast biopsy from 7/2005 to 7/2022. Excluded were cases with less than 2 years of imaging surveillance or a concurrent ipsilateral breast cancer diagnosis within 6 months of the LCIS diagnosis. Final outcomes of cancer versus no cancer were determined by pathology at surgical excision or the absence of cancer on imaging surveillance.

RESULTS

A total of 116 LCIS lesions were identified. The primary imaging findings targeted for percutaneous biopsy included calcifications (50.0%, 58/116), MR enhancing lesions (25.0%, 29/116), noncalcified mammographic architectural distortions (10.3%, 12/116), or masses (14.7%, 17/116). Surgical excision was performed in 49.1% (57/116) and imaging surveillance was performed in 50.9% (59/116) of LCIS cases. There were 22 cancers of which 11 cancers were discovered at immediate excision [19.3% (11/57) immediate upgrade] and 11 cancers developed later while on imaging surveillance [18.6% (11/59) delayed risk for cancer]. Among all 22 cancers, 63.6% (14/22) occurred at the site of LCIS (11 at immediate excision and 3 at surveillance) and 36.4% (8/22) occurred at a location away from the site of LCIS (6 in a different quadrant and 2 in the contralateral breast).

CONCLUSION

LCIS has both an immediate risk (19.3%) and a delayed risk (18.6%) for cancer with 90.9% occurring in the ipsilateral breast (63.6% at and 27.3% away from the site of LCIS) and 9.1% occurring in the contralateral breast.

The morphologic spectrum of lobular carcinoma in situ (LCIS) observations on clinical significance, management implications and diagnostic pitfalls of classic, florid and pleomorphic LCIS

Lobular carcinoma in situ (LCIS) is a non-invasive proliferation of atypical dyscohesive epithelial cells characterized by loss or functional alteration of E-cadherin-mediated cell adhesion. The morphologic spectrum of LCIS encompasses classic (C-LCIS), florid (F-LCIS) and pleomorphic LCIS (P-LCIS), as recently defined by the World Health Organization (WHO) Expert Consensus Group. Atypical lobular hyperplasia (ALH) is also part of this spectrum.This article highlights the morphologic and immunohistochemical features of the three forms of LCIS and summarizes their management implications and prognosis, with emphasis on F-LCIS and P-LCIS.

Invasive Lobular Carcinoma of the Breast With Rectal Metastasis: A Rare Case Report

The rectum is a relatively unusual site for metastasis from invasive lobular carcinoma (ILC) of the breast, and it carries dangers such as perforation and blockage. We reported a case of a 47-year-old female patient complaining of breast ILC for one year. Recently, the patient complained of abdominal distention, mild generalized abdominal pain, and weight loss. The abdominal ultrasound (US) showed moderate ascites without hepatomegaly, and ascitic tapping was positive for malignant cells. Lower colonoscopy showed a congested mass of 8 cm, and anal verge biopsy showed colonic mucosa laminal propria infiltrated with atypical cells and adenocarcinoma metastatic from the breast. In a patient with breast cancer, particularly ILC, who has developed new gastrointestinal tract (GIT) symptoms, there is significantly a high chance of rectal metastatic illness. Early detection is critical for successful treatment.

Descriptive study comparing outcomes of classic and nonclassic lobular carcinoma in situ (florid and pleomorphic) initially diagnosed on core needle biopsy

The lobular carcinoma in situ (LCIS) subtypes include classic (CLCIS), pleomorphic (PLCIS), and florid LCIS (FLCIS). The CLCIS is considered a breast cancer risk factor, but clinical significance and natural history of other LCIS subtypes are unclear. The outcome data on PLCIS and FLCIS is limited. The aim of current study is to compare excision and follow-up findings of CLCIS and nonclassic LCIS (NCLCIS). The breast needle biopsies (NBs) with LCIS during 01/2007-12/2017 were identified. The imaging, clinical findings, and outcome were compared between CLCIS and NCLCIS. A total of 36 NBs from 32 patients with NCLCIS (14 PLCIS & 22 FLCIS) and 73 NBs from 68 patients with CLCIS were identified. The NCLCIS patients were older (57 vs 52 years; P = .02) and presented more often with calcifications (78% vs 44%; P = .01). Seven (19%) PLCIS were initially diagnosed as ductal carcinoma in situ (DCIS). The microscopic invasion was frequent with NCLCIS (25%). No invasion was identified in NBs with CLCIS. A separate concurrent NBs with a carcinoma (29% vs 6%; P = .018) or ductal atypia (12% vs 3%; P = .1) was more frequent with CLCIS. The upgrade rate (invasion or DCIS) was higher with NCLCIS (25% vs 4%). Four NCLCIS developed ipsilateral recurrences: 2 NCLCIS, 1 IDC, and 1 ILC (50; 10-96 months). No breast event was reported in 24 pure CLCIS (60; 8-144 months). Invasive carcinoma with NCLCIS, unlike CLCIS, is always lobular type. Recurrences following NCLCIS are ipsilateral lobular tumors. NCLCIS subtypes are nonobligate precursors to invasive lobular carcinoma.

Inter-observer reproducibility of classical lobular neoplasia (B3 lesions) in preoperative breast biopsies: a study of the Swiss Working Group of breast and gynecopathologists

PURPOSE

Classical type of lobular neoplasia (LN) spans a spectrum of disease, including atypical lobular hyperplasia (ALH) and lobular carcinoma in situ (LCIS), classical lobular neoplasia (LN), and the three-tiered classification of lobular intraepithelial neoplasia (LIN-1, -2, -3). This study addressed inter-observer variability of classical lobular neoplasias (LN) (B3 lesions) in preoperative breast biopsies among breast and gynecopathologists METHODS: A retrospective, observational, cross-sectional study was conducted. 40 preoperative digital images of breast core/vacuum biopsies were analyzed by eight experienced breast- and gynecopathologists. Evaluation criteria were ALH, LCIS, LN classic, LIN-1, LIN-2, LIN-3, focal B3 (one focus), extensive B3 (> one focus). Kappa-index and Chi-square tests were used for statistics. Digital scanned slides were provided to each participant. Agreement between the categories was defined as at least six of eight (cut-off 75%) concordant diagnoses.

RESULTS

The highest agreement between eight pathologists was reached using the category lobular neoplasia (LN, classical), 26/40 (65%) cases were diagnosed as such. Agreements in other categories was low or poor: 12/40 (30%) (ALH), 9/40 (22%) (LCIS), 8/40 (20%) (LIN-1), 8/40 (20%) (focal B3), 3/40 (7.5%) (LIN-2), and 2/40 (5%) (extensive B3). Chi-square-test (classical LN versus the other nomenclatures) was significant (p = 0.001137).

CONCLUSION

Our data suggest that among Swiss breast pathologists, the most reproducible diagnosis for B3 lobular lesions is the category of classical LN. These data further support lack of consistent data in retrospective studies using different terminologies. Validation of reproducible nomenclature is warranted in further studies. This information is useful especially in view of retro- and prospective data analysis with different diagnostic categories.

Lobular neoplasia and invasive lobular breast cancer: Inter-observer agreement for histological grading and subclassification

Lobular neoplasia (LN), invasive lobular breast cancer (ILBC) and related pleomorphic variants represent a distinct group of neoplastic mammary gland lesions. This study assessed the inter-observer agreement of histological grading in a series of ILBC and LN. 54 cases (36x ILBC, 18x LN) were evaluated by 17 observers. 3978 classification calls on various histological features, including nuclear grade, proliferative activity (Ki67 immunohistochemistry, categorical scoring), histological grade and pleomorphism were obtained. Pairwise Cohen's kappa values were calculated and compared between various features and different observer subsets with variable histomorphological experience. In ILBC, pairwise inter-observer agreement for histological grade ranged from poor to almost perfect concordance and was higher in advanced and experienced histopathologists compared with beginners (P < 0.001). Agreement for proliferation (Ki67) ranged from slight to almost perfect concordance and was also higher in advanced and experienced histopathologists (P < 0.001). Considering different features, agreement for proliferation (Ki67) was superior to agreement for histological grade and nuclear grade, even among advanced and experienced histopathologists (P < 0.001). In LN, agreement for B-classification ranged from poor to almost perfect concordance and was higher in advanced and experienced histopathologists (P < 0.001). Considering different features, agreement for proliferation (Ki67 in LN) was superior to subclassification agreement based on conventional features, such as acinar distention and nuclear grade (P < 0.001). In summary, pairwise inter-observer concordance of histological grading of ILBC and LN is dependent on histomorphological experience. Assessment of proliferation by Ki67 immunohistochemistry is associated with favorable inter-observer agreement and can improve histological grading of ILBC as well as LN.