Diagnostic accuracy of fine-needle aspiration cytology of the breast in Japan: Report from the Working Group on the Accuracy of Breast Fine-Needle Aspiration Cytology of the Japanese Society of Clinical Cytology

RNA recovery from specimens of duct-washing cytology performed contemporaneously with mammary ductoscopy

Objective

Conventional cytological diagnosis including duct-washing cytology (DWC) is sometimes performed using ductal epithelial cells collected during mammary ductoscopy; it is useful for detection of early-stage breast cancer such as ductal carcinoma in situ (DCIS). However, conventional cytological diagnosis focuses exclusively on cellular morphology; false negatives and false positives may be caused by inadequate specimen preparation (triggering cell degeneration) or poor examiner diagnostic skills. Molecular diagnosis using RNA biomarkers is expected to compensate for the weaknesses of cytological diagnosis. We previously employed microarray analysis to identify highly expressed genes in DCIS, suggesting that they may be useful for DCIS diagnosis. Here, we explored whether DWC samples yielded RNA of sufficient quantity and quality for RNA biomarker-based diagnosis.

Results

We extracted RNAs from 37 DWC samples. RNA from 12 samples exhibited RNA integrities of  ≥ 6, indicative of moderate-to-high quality. We then showed that cocaine and amphetamine regulated transcript prepropeptide (CARTPT) and breast cancer-associated transcript 54 (BRCAT54) mRNA—previously shown by microarray analysis to be highly expressed in DCIS—were detectable in these samples. Therefore, DWC samples may be useful for molecular diagnosis involving RNA biomarkers.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-022-05928-1.

Implementation of the International Academy of Cytology Yokohama standardized reporting for breast cytopathology: An 8-year retrospective study

BACKGROUND

The International Academy of Cytology (IAC) Yokohama reporting system was recently proposed to serve as a standardized diagnostic platform for the cytological interpretation of breast fine needle aspiration biopsy (FNAB). Five cytological categories were suggested, linked to a certain risk of malignancy (ROM). The aim of this study was to assess the potency of this newly proposed reporting guideline, with a review of literatures.

METHODS

This is a retrospective study over 8-year duration in which all the breast FNABs performed in our institution were recategorized in accordance to the IAC Yokohama reporting system. Kappa coefficient was used to evaluate the agreement between the proposed cytological category and corresponding histological diagnosis, with the level of significance set at 5%. Cyto-histopathological correlation and its diagnostic performance were also assessed.

RESULTS

A total of 1136 breast FNABs were analyzed, including 31 repeat FNABs. Of these, 521 (47.1%) cases had matched histopathological results. Respective ROM for each category was: "insufficient" 13.6%, "benign" 0.4%, "atypical" 25.0%, "suspicious" 85.7%, and "malignant" 100%. There was substantial agreement (κ=0.757) between cytology and histopathological results. Our data revealed a high-diagnostic specificity, sensitivity, positive and negative predictive value of 99.3% (95% CI: 97.6%-99.9%), 94.2% (95% CI: 87.9%-97.9%), 98.0% (95% CI: 92.5%-99.5%), 98.0% (95% CI: 96.1%-99.1%) respectively when both the "suspicious" and "malignant" cases were considered as positive tests, with area under the curve of 0.993.

CONCLUSIONS

The IAC Yokohama system is a reliable, evidence-based, and standardized reporting system that helps to facilitate communication among cytopathologists, radiologists, and surgeons toward individualized patient management.

Breast Fine-Needle Aspiration Practice in 2019: Results of a College of American Pathologists National Survey

CONTEXT.—

The College of American Pathologists surveys provide national benchmarks of pathology practice for laboratories.

OBJECTIVE.—

To investigate breast fine-needle aspiration (FNA) biopsy practice in domestic and international laboratories in 2019.

DESIGN.—

We analyzed data from the College of American Pathologists Breast FNA Practice Supplemental Questionnaire that was distributed to laboratories participating in the 2019 College of American Pathologists Non-Gynecologic Cytopathology Education Program.

RESULTS.—

Sixty-one percent (499 of 816) of respondent laboratories routinely evaluated breast FNAs. Cystic lesions were the most common indication, and radiologists primarily performed FNAs in most settings. Forty-five percent (220 of 491) of laboratories performed ancillary studies on breast FNA samples, but 33.8% (70 of 207) did not report fixation time for breast biomarker studies. Only 54.5% (271 of 497) of laboratories had a standardized reporting system and only 16.8% (82 of 488) were aware of the International Academy of Cytology Yokohama Breast FNA Biopsy Cytology Reporting System. There were significant differences among different types of institutions in several aspects of breast FNA practice, including frequency of concurrent FNA and core needle biopsy for the same lesion, primary personnel who performed the FNA, etc. Significant differences existed between domestic and international laboratories in slide preparation, ancillary studies, fixation time reporting, standardized/descriptive diagnosis, and International Academy of Cytology Yokohama Reporting System awareness.

CONCLUSIONS.—

This is the first survey from the College of American Pathologists Cytopathology Committee to investigate breast FNA practices. The data reveal significant differences in breast FNA practice among different types of institutions and between domestic and international laboratories, and provide a baseline for future breast FNA studies in a variety of practice settings.

Fine-Needle Aspiration Cytology (FNAC) is a reliable diagnostic tool for small breast lesions (≤ 1.0 cm): a 20-year retrospective study

Background

Breast cancer is a major public health problem worldwide. It is recommended that small breast lesions or those suspicious for malignancy be evaluated via histopathological examination (“core biopsy” or surgical specimens), and lesions that are probably benign and palpable should be examined via fine-needle aspiration cytology (FNAC). This study aimed to assess the accuracy of FNAC for the diagnosis of small breast lesions.

Methods

We reviewed all anatomopathological reports of FNACs collected between January 1, 2000 and December 31, 2019 (n = 24,721) in a private community pathology service. Lesions up to 1.0 cm (≤1.0 cm) (n = 8334) were included for evaluation and classified according to the recommendation of the International Academy of Cytology Yokohama System for Reporting Breast Fine Needle Aspiration Biopsy Cytopathology in the following categories: (1) insufficient/inadequate; (2) benign; (3) atypical, probably benign; (4) suspicious of malignancy; and (5) malignant. Subsequently, the results of the FNACs were compared to those of the respective histopathological examinations (n = 785).

Results

FNAC had a specificity of 99.6%; sensitivity, 97.4%; positive predictive value, 99.6%; negative predictive value, 97.6%; and accuracy, 98.5%.

Conclusions

FNAC is a reliable method for diagnosing small breast lesions (≤1.0 cm).

DIAGNOSTIC ACCURACY OF FNAC VERSUS OPEN BIOPSY IN DIAGNOSING CARCINOMA BREAST IN PALPABLE ADULT FEMALE BREAST LESIONS IN POPULATION OF KHYBER PAKHTUNKHWA, PAKISTAN

Background: FNAC is usually considered as a reliable, easily performed and inexpensive test for diagnosing palpable lesions of breasts with a high degree of accuracy. The objective of this study was to compare the diagnostic accuracy of fine needle aspiration cytology (FNAC) versus open biopsy in carcinoma breast in adult palpable female breast lesions in population of Khyber Pakhtunkhwa, Pakistan. Material and Methods: This cross-sectional study was conducted at Department of Pathology, Lady Reading Hospital, Peshawar, Pakistan from 1st January 2019 to 31st December 2019. Sixty (60) FNAC reports of palpable breast lesions in definitive categories {(C2 (benign) and C5 (malignant)} with respective open biopsy reports were included in the study. Nine (9) FNAC reports of inconclusive categories (C1, C3 & C4) were excluded. Age in years was a single demographic variable. The data for “presence of carcinoma breast” for both the open biopsy and FNAC were placed in two-by-two table. Sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of FNAC were determined as percentages with confidence intervals at 95% confidence level. Results: The mean age of the sample was 37 ± 17 (17-70, range 53) years. Out of 60 cases on open biopsy, 14 (23.33%) were confirmed as having and 46 (76.67%) as not having carcinoma breast and on FNAC, 12 (20%) were positive and 48 (80%) were negative for carcinoma breast. Two-by-two table showed 12 true positive (TP), 46 true negative (TN), two false negative (FN) and zero false positive (FP) cases. The sensitivity of FNAC was 85.71%, specificity 100%, PPV 100%, NPV 95.83% and accuracy was 96.67%. Conclusion: FNAC is a reliable method in diagnosing carcinoma breast in adult palpable female breast lesions in population of Khyber Pakhtunkhwa, Pakistan.

Breast fine needle aspiration biopsy cytology: the potential impact of the International Academy of Cytology Yokohama System for Reporting Breast Fine Needle Aspiration Biopsy Cytopathology and the use of rapid on-site evaluation

The present report reviews the current problems associated with the routine use of breast fine needle aspiration biopsy (FNAB) and discusses the potential impact that the new International Academy of Cytology (IAC) Yokohama Reporting System and the use of rapid on-site evaluation (ROSE) should have on reducing these problems to optimize breast care for patients. The recently reported IAC System aims to establish the best practice guidelines for breast FNAB, emphasizing the importance of the FNAB technique and the skillful preparation of direct smears. The IAC System proposes a standardized report and established clear terminology for defined reporting categories, each of which has a risk of malignancy and is linked to management options. The FNAB techniques that will optimize the biopsy specimen and reduce poor quality smears are reviewed and the benefits of ROSE are discussed. FNAB can diagnose accurately the vast majority of breast lesions, and ROSE has been recommended whenever possible to reduce the rate of insufficient/inadequate cases and increase the number of specific benign and malignant diagnoses. ROSE performed by a cytopathologist provides a provisional diagnosis, reducing patient anxiety and facilitating management through cost-effective immediate triage and patient selection for ancillary testing. Thus, patients can be selected for immediate core needle biopsy, as required.

Fluorescence-based discrimination of breast cancer cells by direct exposure to 5-aminolevulinic acid

Protoporphyrin IX-fluorescence measurement is a powerful in situ approach for cancer detection after oral/topical administration of 5-aminolevulinic acid. However, this approach has not been clinically established for breast cancer, probably due to insufficient delivery of 5-aminolevulinic acid to the mammary glands. In the present study, we directly exposed breast cancer cells to 5-aminolevulinic acid to assess their discrimination via protoporphyrin IX-fluorescence. Fluorescence intensity (FI) was measured in the human breast cancer cell lines MCF7 and MDA-MB-231 and breast epithelial cell line MCF10A by confocal microscopy and flow cytometry. After 5-aminolevulinic acid exposure for 2 hours, protoporphyrin IX-FI in MCF7 and MDA-MB-231 cells significantly increased with marked cell-to-cell variability, whereas that in MCF10A cells increased moderately. Combined exposure of the cancer cells to 5-aminolevulinic acid and Ko143, a specific inhibitor of ATP-binding cassette transporter G2, further increased protoporphyrin IX-FI and alleviated the cell-to-cell variability in MCF7 and MDA-MB-231 cells, indicating improvement in the reproducibility and accuracy for fluorescence-based cancer detection. The increased FI by combined administration of these two drugs was also demonstrated in cells obtained via fine needle aspiration from mouse xenograft models inoculated with MDA-MB-231 cells. Furthermore, a cutoff value for increased protoporphyrin IX-FI ratio, before and after exposure to these drugs, clearly discriminated between cancer and noncancer cells. Taken together, direct exposure to 5-aminolevulinic acid and Ko143 may be a promising strategy for efficient fluorescence-based detection of breast cancer cells ex vivo using fine needle aspiration.

Usefulness of second-look ultrasonography using anatomical breast structures as indicators for magnetic resonance imaging-detected breast abnormalities

Background

Second-look ultrasonography (US) is commonly performed for breast lesions detected using magnetic resonance imaging (MRI), but the identification rate of these lesions remains low. We investigated if US methods using anatomical breast structures can improve the lesion identification rate of MR-detected lesions and evaluated the diagnostic performance of fine-needle aspiration cytology (FNAC) of the second-look US using the above-mentioned method.

Methods

We retrospectively assessed 235 breast lesions (hereinafter, “targets”) subjected to second-look US following MRI between January 2013 and September 2015. US was employed using the conventional methods, and this assessment measured the positional relationships of lesions with regard to surrounding anatomical breast structures (glandular pattern, Cooper’s ligaments, adipose morphology, and vascular routes). Associations were assessed among the following variables: the MRI findings, target size, identification rate, and main US indicators that led to identifying the target; FNAC results and MRI findings; MRI findings and histopathological findings; and FNAC results and histopathological findings. Moreover, the sensitivity and specificity of FNAC were determined.

Results

The identification rate was 99%. The main US indicators leading to identification were a glandular pattern (28–30% of lesions) and other breast structures (~ 25% of lesions). FNAC was performed for 232 targets with the following results: sensitivity of 85.7%, specificity of 91.6%, PPV of 94.1%, NPV of 92.9%, false-negative rate of 14.3%, false-positive rate of 2.1%, and accuracy of 89.7%.

Conclusions

Second-look US using anatomical breast structures as indicators and US-guided FNAC are useful for refining the diagnosis of suspicious breast lesions detected using MRI.

Identification of Axillary Lymph Node Metastasis in Patients With Breast Cancer Using Dual-Phase FDG PET/CT

OBJECTIVE. The aim of this study was to assess the diagnostic performance of dual-phase ¹⁸F-FDG PET/CT in detecting axillary lymph node metastasis in patients with breast cancer. MATERIALS AND METHODS. A total of 826 patients with breast cancer were retrospectively evaluated. PET/CT scans were performed 1 hour and 2 hours after FDG administration before treatment. The maximum standardized uptake value (SUV_max) in the axillary lymph node at both time points (hereafter referred to as SUV_max1 and SUV_max2, respectively) and the retention index (RI) were calculated. RESULTS. Axillary lymph node metastasis was detected in 285 of 826 patients (34.5%). The median axillary SUV_max1, SUV_max2, and RI in patients with nodal metastasis were higher than those in patients without metastasis (1.5 vs 0.6, 1.6 vs 0.5, and 7.7 vs -3.7, respectively; all p < 0.001). The diagnostic accuracy of axillary SUV_max1 and SUV_max2 was equivalent, and the sensitivity and specificity of SUV_max1 were 74.7% and 83.4%, respectively. Although the performance of the axillary RI was inferior to that of SUV_max1 and SUV_max2, both the SUV_max and the RI were independent predictors of nodal metastasis, and a positive RI suggested axillary lymph node involvement when the SUV_max1 was significantly high. Of 533 patients with category T1-2 breast cancer without lymph node swelling, 101 (19.0%) had pathologic lymph node involvement; the negative predictive value of axillary SUV_max1 was 86.8%. CONCLUSION. Delayed phase imaging identified axillary lymph node metastasis as accurately as standard PET/CT. A high negative predictive value of PET/CT for the detection of nodal metastasis is helpful to avoid surgical axillary assessment in patients with category T1-2 breast cancer without lymph node swelling.

International Academy of Cytology Yokohama System for Reporting Breast Fine-Needle Aspiration Biopsy Cytopathology: A Review of Predictive Values and Risks of Malignancy

OBJECTIVE

We aimed to assess the risk of malignancy (ROM) and predictive values in prior breast cytology studies as a basis for the new International Academy of Cytology (IAC) Yokohama system for reporting breast fine-needle aspiration biopsy (FNAB) cytology, which classifies cytologic diagnoses into 5 categories: (1) insufficient material, (2) benign, (3) atypical, (4) suspicious of malignancy, and (5) malignant.

STUDY DESIGN

Publications between January 1, 1997, and December 31, 2017, that studied the performance characteristics of FNAB from palpable and nonpalpable breast masses were identified through the PubMed database. Data for number of total cases and cases within each diagnostic category, if available, were collected. Performance characteristics, including absolute sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and ROM for each category were recorded or, when possible, calculated.

RESULTS

The literature review resulted in a case cohort of 33,341 breast FNABs, drawn from 27 studies. Pooling these cases together, the ROM for insufficient material, benign, atypical, suspicious, and malignant were 30.3, 4.7, 51.5, 85.4, and 98.7%, respectively. The complete sensitivity and specificity were 96.3 and 98.8%, correspondingly. The PPV and NPV were 98.7 and 95.3%, correspondingly. The false-negative and false-positive rates were 3.7 and 1.0%, respectively.

CONCLUSIONS

This meta-analysis demonstrates that the diagnostic categories of the new IAC Yokohama System each carry an implied ROM, which increases from the benign to malignant categories. This study also shows the high sensitivity and specificity of FNAB for breast lesions.

The International Academy of Cytology Yokohama System for Reporting Breast Fine-Needle Aspiration Biopsy Cytopathology

The International Academy of Cytology (IAC) gathered together a group of cytopathologists expert in breast cytology who, working with clinicians expert in breast diagnostics and management, have developed the IAC Yokohama System for Reporting Breast Fine-Needle Aspiration Biopsy (FNAB) Cytology. The project was initiated with the first cytopathology group meeting in Yokohama at the 2016 International Congress of Cytology. This IAC Yokohama System defines five categories for reporting breast cytology, each with a clear descriptive term for the category, a definition, a risk of malignancy (ROM) and a suggested management algorithm. The key diagnostic cytopathology features of each of the lesions within each category will be presented more fully in a subsequent atlas. The System emphasizes that the crucial requirements for diagnostic breast FNAB cytology are a high standard for the performance of the FNAB and for the making of direct smears, and well-trained experienced cytopathologists to interpret the material. The performance indicators of breast FNAB, including specificity and sensitivity, negative predictive value, positive predictive value and ROM stated in this article have been derived from the recent literature. The current practice of breast FNAB has evolved with the increasing use of ultrasound guidance and rapid on-site evaluation. Two recent publications have shown a range of ROM for the insufficient/inadequate category of 2.6-4.8%, benign 1.4-2.3%, atypical 13-15.7%, suspicious of malignancy 84.6-97.1%, and malignant 99.0-100%. The management algorithm in the System provides options because there are variations in the management of breast lesions using FNAB and core-needle biopsy in those countries utilizing the "triple test" of clinical, imaging, and FNAB assessment, and also variations in the availability of CNB and imaging in low- and middle-income countries. The System will stimulate further discussion and research, particularly in the cytological diagnostic features of specific lesions within each category and in management recommendations. This will lead to continuing improvements in the care of patients with breast lesions and possible modifications to the IAC Yokohama System.

Strategy for the accurate preoperative evaluation of the number of metastatic axillary lymph nodes in breast cancer

BACKGROUND

After the ACOSOG Z0011 trial, it became important to evaluate the number of metastatic axillary lymph nodes (LNs) preoperatively. The purpose of this paper is to confirm whether the number of metastases can be accurately diagnosed by preoperative computed tomography (CT), ultrasound sonography (US), and US-guided fine-needle aspiration cytology (FNAC).

METHODS

We retrospectively analyzed the axillary LNs finding of preoperative CT/US of 470 breast cancer patients. Metastasis was suspected based on the following findings: LNs with a long-axis diameter of ≥10 mm or a short-axis diameter of ≥5 mm on CT, and LNs with the absence of a fatty hilum, focal cortical thickness or a cortical thickness ≥2 mm on US. We also examined the results of FNAC making a rapid bedside diagnosis (bedside-FNAC) of 162 LNs that were suspected to metastatic based on the US findings.

RESULTS

On CT, all cases with ≥3 LNs with a long-axis diameter of ≥10 mm and a short-axis diameter of ≥5 mm had metastasis. However, there was no relationship between the number of detected LNs and the number of metastases. On US, 75.7% of LNs with the absence of a fatty hilum and all LNs with cortical thickness ≥6 mm had metastasis. The accuracy of bedside-FNAC for suspicious LNs was 100%.

CONCLUSIONS

Although we can pick up LNs that are likely to have metastasis on CT/US, it was impossible to accurately predict the number of metastases on CT/US. However, bedside-FNAC of suspicious LNs could accurately predict the number of metastases.

Diagnostic Performance of Ultrasound-Guided Fine-Needle Aspiration of Nonpalpable Breast Lesions in a Multidisciplinary Setting: The Institut Curie's Experience

OBJECTIVES

To assess the diagnostic performance of ultrasound-guided fine-needle aspiration (USFNA) in nonpalpable breast lesions (NPBLs) in a multidisciplinary setting.

METHODS

In total, 2,601 NPBLs underwent USFNA by a radiologist-pathologist team. Gold-standard diagnosis was based on surgery, core-needle biopsy, or 1-year imaging follow-up. USFNA's diagnostic performance was analyzed in different clinical and imaging subgroups.

RESULTS

USFNA's sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were, respectively, 92.6% (95% confidence interval [CI], 90.8%-94.2%), 96.8% (95% CI, 95.8%-97.6%), 94.8% (95% CI, 93.2%-96.1%), and 95.4% (95% CI, 94.3%-96.4%). The best PPV was achieved in Breast-Imaging Reporting and Data System (BI-RADS) categories 4C and 5 and the best NPV in BI-RADS categories 2, 3, and 4A and in patients younger than 50 years. The mitotic count, BI-RADS categories, associated palpable cancer, and age (<50 or ≥50 years) were statistically independent factors ( P  < .05) between USFNA's false-negative and true-positive results.

CONCLUSIONS

USFNA is a robust diagnostic procedure in NPBLs. Age and the BI-RADS category of the lesion are important factors determining its performance.

Breast fine needle aspiration continues to be relevant in a large academic medical center: experience from Massachusetts General Hospital

Fine needle aspiration (FNA) is increasingly being supplanted by core needle biopsy. However, breast surgeons continue to rely on FNA at our institution. This retrospective study evaluated breast FNA for its diagnostic accuracy and breast cancer biomarker testing utility. All breast FNAs performed at Massachusetts General Hospital 2009-2015 were reviewed. Cytology diagnoses were compared with subsequent tissue or clinical diagnoses. Immunohistochemistry and fluorescence in situ hybridization (FISH) results using formalin-fixed paraffin-embedded (FFPE) cell blocks and histologic tissue blocks were compared. 1654 consecutive breast FNAs were included. Breast FNA demonstrated the following diagnostic performance: positive predictive value of malignant cytology diagnosis 100 %, negative predictive value of benign cytology diagnosis 97.5 %, complete sensitivity 91.6 %, and specificity 95.5 %. Concordance rates for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2) immunohistochemistry, and HER2 FISH were 98.2 % (κ = 0.95, p < 0.001), 100.0 % (κ = 1.000, p < 0.001), 83.1 % (κ = 0.69, p < 0.001), and 93.5 % (κ = 0.785, p < 0.001), respectively. Review of consecutive breast FNAs in a large cohort confirmed the excellent accuracy of this biopsy technique for breast lesion diagnosis. FNA FFPE cell blocks collected in the course of routine clinical care are adequate, practical, and reliable for breast cancer biomarker testing.

Pathological examination of breast cancer biomarkers: current status in Japan

This article reviews the current status of pathological evaluation for biomarkers in Japan. The introduced issues are the international trends for estimation of biomarkers considering diagnosis and treatment decision, and pathological issues under discussion, and how Japanese Breast Cancer Society (JBCS) members have addressed issues related to pathology and biomarkers evaluation. As topics of immunohistochemical study, (1) ASCO/CAP guidelines, (2) Ki67 and other markers, (3) quantification and image analysis, (4) application of cytologic samples, (5) pre-analytical process, and (6) Japan Pathology Quality Assurance System are introduced. Various phases of concepts, guidelines, and methodologies are co-existed in today's clinical practice. It is expected in near future that conventional methods and molecular procedures will be emerged, and Japanese Quality assurance/Quality control (QA/QC) system will work practically. What we have to do in the next generation are to validate novel procedures, to evaluate the relationship between traditional concepts and newly proposed ideas, to establish a well organized QA/QC system, and to standardize pre-analytical process that are the basis of all procedures using pathological tissues.

Characteristics of the Japanese histological classification for breast cancer: correlations with imaging and cytology

The Japanese histological classification of breast cancer is a unique classification that was published as the 2nd edition of the General Rules for Clinical and Pathological Recording of Breast Cancer in 1971. According to this classification, breast cancers are divided into three subgroups: noninvasive, invasive, and Paget's disease. Invasive carcinomas are further divided into two groups: invasive ductal carcinomas (IDCs) and special types. IDCs are the most common types, representing 70-80 % of all breast cancers, and most of them correspond to invasive carcinoma-not special type-according to the latest WHO classification (4th edition). In particular, IDCs are subdivided into three subgroups as follows: (1) papillotubular carcinoma, which is characterized by the projection of papillae into spaces, and includes cribriform and comedo patterns; (2) solid-tubular carcinoma, which is a solid cluster of cancer cells with expansive growths that form relatively sharp borders; and (3) scirrhous carcinoma, which grows in a scirrhous manner characterized by cancer nests or cells accompanied by marked fibrosis. The concept of subclassification originated in Japan. The Japanese histological classification has taken on important roles since its publication, in particular for comparisons between histology and imaging or cytology.