Cat Scratch Disease of the Breast/Axilla: Recognition of a Rare Disease and Approaches for Differential Diagnosis.

Cat scratch disease rarely presents as a breast or axillary mass mimicking carcinoma both clinically and radiologically. Diagnosing breast/axillary cat scratch disease is challenging due to its rarity and nonspecific findings. Here, we reported 2 patients with breast cat scratch disease and reviewed 14 patients with cat scratch disease involving breast/axilla from the past 30 years. It mainly affects women (median age: 48), consistently presenting as axillary lymphadenopathy, and demonstrates ipsilateral breast mass in half of patients (50%, 8/16). The breast mass was most commonly located in the upper outer quadrant (88%, 7/8), indicating the possibility of disease extension from axillary adenopathy. Around half of patients (56%, 9/16) reported cat exposure. Histologically, most patients (93%, 14/15) presented as necrotizing granulomas, with characteristic stellate-shaped necrosis in 5 patients. Although pathologic differential diagnoses between cat scratch disease and cancer are straightforward, distinguishing cat scratch disease from other granulomatous mastitis poses diagnostic challenges. Silver stains should be included in the diagnostic workup panel when highly suspecting cat scratch disease clinically. However, they were only able to highlight the causative microorganism in 54% (7/18) patients, and the gram stain was negative in all 12 tested patients. In contrast, polymerase chain reaction (PCR) for the causative microorganism was consistently positive in all 3 tested patients, while serologic test confirmed diagnosis in 85% (11/13) patients; 1 patient with negative serology showed a positive PCR result. Therefore, upfront PCR tests with or without serologic study should be considered to confirm the diagnosis of cat scratch disease in a timely manner.

Spatial analyses of immune cell infiltration in cancer: current methods and future directions: A report of the International Immuno-Oncology Biomarker Working Group on Breast Cancer.

Modern histologic imaging platforms coupled with machine learning methods have provided new opportunities to map the spatial distribution of immune cells in the tumor microenvironment. However, there exists no standardized method for describing or analyzing spatial immune cell data, and most reported spatial analyses are rudimentary. In this review, we provide an overview of two approaches for reporting and analyzing spatial data (raster versus vector-based). We then provide a compendium of spatial immune cell metrics that have been reported in the literature, summarizing prognostic associations in the context of a variety of cancers. We conclude by discussing two well-described clinical biomarkers, the breast cancer stromal tumor infiltrating lymphocytes score and the colon cancer Immunoscore, and describe investigative opportunities to improve clinical utility of these spatial biomarkers. © 2023 The Pathological Society of Great Britain and Ireland.

Pitfalls in machine learning-based assessment of tumor-infiltrating lymphocytes in breast cancer: A report of the International Immuno-Oncology Biomarker Working Group on Breast Cancer

The clinical significance of the tumor-immune interaction in breast cancer is now established, and tumor-infiltrating lymphocytes (TILs) have emerged as predictive and prognostic biomarkers for patients with triple-negative (estrogen receptor, progesterone receptor, and HER2-negative) breast cancer and HER2-positive breast cancer. How computational assessments of TILs might complement manual TIL assessment in trial and daily practices is currently debated. Recent efforts to use machine learning (ML) to automatically evaluate TILs have shown promising results. We review state-of-the-art approaches and identify pitfalls and challenges of automated TIL evaluation by studying the root cause of ML discordances in comparison to manual TIL quantification. We categorize our findings into four main topics: (1) technical slide issues, (2) ML and image analysis aspects, (3) data challenges, and (4) validation issues. The main reason for discordant assessments is the inclusion of false-positive areas or cells identified by performance on certain tissue patterns or design choices in the computational implementation. To aid the adoption of ML for TIL assessment, we provide an in-depth discussion of ML and image analysis, including validation issues that need to be considered before reliable computational reporting of TILs can be incorporated into the trial and routine clinical management of patients with triple-negative breast cancer. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Computational pathology improves risk stratification of a multi-gene assay for early stage ER+ breast cancer.

Prognostic markers currently utilized in clinical practice for estrogen receptor-positive (ER+) and lymph node-negative (LN-) invasive breast cancer (IBC) patients include the Nottingham grading system and Oncotype Dx (ODx). However, these biomarkers are not always optimal and remain subject to inter-/intra-observer variability and high cost. In this study, we evaluated the association between computationally derived image features from H&E images and disease-free survival (DFS) in ER+ and LN- IBC. H&E images from a total of n = 321 patients with ER+ and LN- IBC from three cohorts were employed for this study (Training set: D1 (n = 116), Validation sets: D2 (n = 121) and D3 (n = 84)). A total of 343 features relating to nuclear morphology, mitotic activity, and tubule formation were computationally extracted from each slide image. A Cox regression model (IbRiS) was trained to identify significant predictors of DFS and predict a high/low-risk category using D1 and was validated on independent testing sets D2 and D3 as well as within each ODx risk category. IbRiS was significantly prognostic of DFS with a hazard ratio (HR) of 2.33 (95% confidence interval (95% CI) = 1.02-5.32, p = 0.045) on D2 and a HR of 2.94 (95% CI = 1.18-7.35, p = 0.0208) on D3. In addition, IbRiS yielded significant risk stratification within high ODx risk categories (D1 + D2: HR = 10.35, 95% CI = 1.20-89.18, p = 0.0106; D1: p = 0.0238; D2: p = 0.0389), potentially providing more granular risk stratification than offered by ODx alone.

Breast MALT Lymphoma: A Clinical, Histomorphologic, and Immunophenotypic Evaluation.

Introduction. Primary breast extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is rare and understudied. Embryonically, mammary glands are developed as specialized skin appendages. It is possible that overlapping features exist between breast MALT lymphoma and primary cutaneous marginal zone lymphoma. Methods. We studied 5 primary and 6 secondary breast MALT lymphomas diagnosed in our institution during a 20-year period. Clinical and pathologic features of these lymphomas were analyzed and compared. Results. Most primary and secondary breast MALT lymphomas had similar clinical presentations as unilateral breast lesions without axillary lymphadenopathy. However, primary lymphomas tended to be diagnosed in older patients (median: 77 years old) than secondary lymphomas (median: 60 years old). Thyroid abnormality was a common finding in both primary (3/5) and secondary (5/6) lymphomas. Hashimoto's thyroiditis was diagnosed in one primary lymphoma. No distinct histopathologic findings were found in primary lymphomas. Features for primary cutaneous marginal zone lymphoma, including overexpression of IgG and IgG4 and high IgG4/IgG ratio, were absent in all primary but present in one secondary lymphoma with cutaneous origin. This secondary lymphoma also had expansion of CD30-positive cells. Conclusion. Primary breast MALT lymphoma does not share the distinctive features of primary cutaneous marginal zone lymphoma that set it apart from other extranodal marginal zone lymphomas. Having increased IgG- and IgG4-positive cells with a high IgG/IgG4 ratio in breast MALT lymphoma may indicate cutaneous origin. CD30 overexpression may be a feature seen in marginal zone lymphoma of cutaneous origin, which needs further studies to prove.

Automated analysis of computerized morphological features of cell clusters associated with malignancy on bile duct brushing whole slide images.

BACKGROUND: Bile duct brush specimens are difficult to interpret as they often present inflammatory and reactive backgrounds due to the local effects of stricture, atypical reactive changes, or previously installed stents, and often have low to intermediate cellularity. As a result, diagnosis of biliary adenocarcinomas is challenging and often results in large interobserver variability and low sensitivity OBJECTIVE: In this work, we used computational image analysis to evaluate the role of nuclear morphological and texture features of epithelial cell clusters to predict the presence of pancreatic and biliary tract adenocarcinoma on digitized brush cytology specimens. METHODS: Whole slide images from 124 patients, either diagnosed as benign or malignant based on clinicopathological correlation, were collected and randomly split into training (ST , N = 58) and testing (Sv , N = 66) sets, with the exception of cases diagnosed as atypical on cytology were included in Sv . Nuclear boundaries on cell clusters extracted from each image were segmented via a watershed algorithm. A total of 536 quantitative morphometric features pertaining to nuclear shape, size, and aggregate cluster texture were extracted from within the cell clusters. The most predictive features from patients in ST were selected via rank-sum, t-test, and minimum redundancy maximum relevance (mRMR) schemes. The selected features were then used to train three machine-learning classifiers. RESULTS: Malignant clusters tended to exhibit lower textural homogeneity within the nucleus, greater textural entropy around the nuclear membrane, and longer minor axis lengths. The sensitivity of cytology alone was 74% (without atypicals) and 46% (with atypicals). With machine diagnosis, the sensitivity improved to 68% from 46% when atypicals were included and treated as nonmalignant false negatives. The specificity of our model was 100% within the atypical category. CONCLUSION: We achieved an area under the receiver operating characteristic curve (AUC) of 0.79 on Sv , which included atypical cytological diagnosis.

Upgrade rates of intraductal papilloma with and without atypia diagnosed on core needle biopsy and clinicopathologic predictors.

Surgical excision of breast intraductal papilloma (IDP) without atypia diagnosed on core needle biopsy (CNB) is controversial as the risk of upgrade to malignant lesions is not well established. This study investigates upgrade rates of benign and atypical IDP to ductal carcinoma in situ (DCIS) and invasive carcinoma (IC) and clinicopathologic predictors. We identified 556 cases of IDP diagnosed on CNB at a single institution from 2010 to 2020 after excluding patients with a history of breast carcinoma, ipsilateral high-risk lesion, radiologic/pathologic discordance, or less than 2 years of follow-up if no excision within 1 year. Of these, 97 biopsies were consistent with atypical IDP and 459 were benign IDP. Surgical excision was performed for 318 (57.2%), and the remaining 238 (42.8%) underwent active monitoring. The upgrade rate for IDP without atypia was 2/225 (0.9%; 1 DCIS and 1 IC). Of 93 surgically excised atypical IDPs, 19 (20.4%) upgraded (14 DCIS and 5 IC). Of 238 nonexcised IDPs followed clinically (range, 24-140 months, mean 60 months), there was no subsequent breast cancer diagnosed at the IDP site on follow-up. Mean age of patients was 56 yr ± 12.6 SD without upgrade, 63 yr ± 10.6 SD (P = .027) with DCIS, and 61 yr ± 10.8 SD (P = .35) with IC. Atypical IDP was more likely to upgrade if biopsied by stereotactic guidance (8/19, 42.1% P = .035). At our institution, we had an exceedingly low upgrade rate for benign IDP. Overall, patients with upgrade to DCIS were older. For atypical IDP, upgrade was seen in higher proportions of stereotactic biopsies.

High-risk and selected benign breast lesions diagnosed on core needle biopsy: Evidence for and against immediate surgical excision.

The vast majority of image-detected breast abnormalities are diagnosed by percutaneous core needle biopsy (CNB) in contemporary practice. For frankly malignant lesions diagnosed by CNB, the standard practice of excision and multimodality therapy have been well-defined. However, for high-risk and selected benign lesions diagnosed by CNB, there is less consensus on optimal patient management and the need for immediate surgical excision. Here we outline the arguments for and against the practice of routine surgical excision of commonly encountered high-risk and selected benign breast lesions diagnosed by CNB. The entities reviewed include atypical ductal hyperplasia, atypical lobular hyperplasia, lobular carcinoma in situ, intraductal papillomas, and radial scars. The data in the peer-reviewed literature confirm the benefits of a patient-centered, multidisciplinary approach that moves away from the reflexive "yes" or "no" for routine excision for a given pathologic diagnosis.

Cytologic presentation and clinicopathologic correlation of Mullerian carcinosarcoma on serous fluid samples.

INTRODUCTION: Limited data are present to study the cytologic findings of Mullerian carcinosarcoma (MCS) in serous fluid samples and clinicopathologic features that are associated with cytology yield. MATERIALS AND METHODS: We studied 30 MCS patients diagnosed on surgical resection samples, and reviewed their cytomorphology and immunophenotypes on concurrent serous fluid cytology samples. Clinicopathologic features were also compared between cases with positive or negative cytology. RESULTS: Fourteen out of 30 patients showed positive cytology, including 12 patients with only carcinomatous components and 2 with sarcomatous cells. Cytomorphology of MCS was mostly consistent with adenocarcinoma, with psammoma bodies occasionally present. The 2 cases with sarcomatous cells showed spindle cells without signs of heterologous differentiation. PAX8 was positive in 10 of 11 cases, and WT1 was positive in 8 of 11 cases including the case with negative PAX8. In 1 case, PAX8 and WT1 were only positive in the sarcomatous but not in carcinomatous cells. MOC31 showed consistent positivity in carcinomatous cells, which appeared to be more sensitive than B72.3 (positive in 72.7%). In addition, sarcomatous cells showed CD10 positivity in 1 case. Clinically, patients who developed body cavity effusions or with higher stage diseases were more likely to have positive cytology. CONCLUSIONS: Cytologic diagnosis of MCS in the serous fluid is challenging due to the rare presence of sarcomatous component. Staining both PAX8 and WT1 is recommended to confirm their Mullerian origin, although both markers may be positive only in sarcomatous cells. Cytology yield of MCS is highly associated with the disease stage.

Lactotransferrin-Related Breast Amyloidosis: Report of a First Case.

Breast amyloidosis is a rare condition which is mostly associated with hematological disorders or hereditary genetic disorders. Imaging findings of breast amyloidosis can mimic malignancy, which often leads to biopsy or excision of the lesion. Here, we presented a case of localized lactotransferrin-related breast amyloidosis in an elderly female patient. Histologic examination revealed extensive involvement of breast lobules by amorphous amyloid materials, with attenuation of lobular structures and prominent calcifications. Positive immunostains for myoepithelial cells helped to exclude the possibility of invasive carcinoma. The patient had no hematologic malignancy besides immunoglobulin G lambda monoclonal gammopathy of undetermined significance. Mass spectrometry of the breast amyloid identified lactotransferrin and no immunoglobulin or its light chain. On follow-up, the patient showed no recurrence of the breast lesion after local excision nor showed other systematic comorbidities, indicating the benign nature of the lesion. This first report of lactotransferrin-related amyloidosis may represent a special type of localized breast amyloidosis that has no correlation with systematic disorders.

Collagen fiber orientation disorder from H&E images is prognostic for early stage breast cancer: clinical trial validation.

Collagen fiber organization has been found to be implicated in breast cancer prognosis. In this study, we evaluated whether computerized features of Collagen Fiber Orientation Disorder in Tumor-associated Stroma (CFOD-TS) on Hematoxylin & Eosin (H&E) slide images were prognostic of Disease Free Survival (DFS) in early stage Estrogen Receptor Positive (ER+) Invasive Breast Cancers (IBC). A Cox regression model named MCFOD-TS, was constructed using cohort St (N = 78) to predict DFS based on CFOD-TS features. The prognostic performance of MCFOD-TS was validated on cohort Sv (N = 219), a prospective clinical trial dataset (ECOG 2197). MCFOD-TS was prognostic of DFS in both St and Sv, independent of clinicopathological variables. Additionally, the molecular pathways regarding cell cycle regulation were identified as being significantly associated with MCFOD-TS derived risk scores. Our results also found that collagen fiber organization was more ordered in patients with short DFS. Our study provided a H&E image-based pipeline to derive a potential prognostic biomarker for early stage ER+ IBC without the need of special collagen staining or advanced microscopy techniques.

Clinicopathologic and immunohistochemical study of breast angiosarcoma.

Breast angiosarcoma (AS) is a rare malignancy which can be classified into primary or secondary as a result of breast cancer therapy. On histology, breast AS has a wide spectrum of morphologic presentations, and its diagnosis can be challenging based on morphologic evaluation alone. Here, we studied 10 cases of breast AS diagnosed at our institution during a 20-year period, in which 7 cases were radiation-associated AS (RA-AS) and 3 cases were primary AS (P-AS). The average latency between radiotherapy and RA-AS was 8.1 years. RA-AS mostly occurred in breast skin, while all P-AS involved breast parenchyma. All 10 AS cases were high grade, including 4 RA-AS cases demonstrating epithelioid morphology. Histologic morphologies of AS varied from confluent growth of atypical spindle or epithelioid cells to scattered marked pleomorphic cells. Some cases appeared deceptively bland or low grade, but the presence of areas of haemorrhage ('blood lake') or necrosis upgraded them to high grade lesions. Additionally, some epithelioid RA-AS cases with lymphatic differentiation (D2-40 positive) showed pseudopapillary morphology characterized by discohesive cells sloughing off at periphery of vascular cores, resembling papillary breast carcinoma. P-AS did not show prominent vesicular nuclei and/or conspicuous nucleoli, which were features observed in RA-AS. C-MYC immunostain results showed P-AS was completely negative or focal weakly positive in hypercellular areas. In comparison, RA-AS were consistently positive for c-MYC. Epithelioid RA-AS with lymphatic differentiation tended to show stronger and/or more diffuse c-MYC positivity than other AS cases. CD31 and ERG immunostains showed positivity in all cases, while CD34 were negative in some cases with lymphatic differentiation. This study offers a detailed morphologic and immunohistochemical assessment of a rare tumor of the breast that is important to recognize. Common differential diagnosis for breast AS, including post-radiation atypical vascular proliferation (AVP), are also reviewed and discussed.

Clinicopathological Follow-up of Breast DCIS Diagnosed on Biopsies: A Single Institutional Study of 575 Patients.

Stratifying ductal carcinoma in situ (DCIS) patients into different upgrading risk groups is important in exploiting more precise therapeutic options. Evaluation of estrogen receptor/progesterone receptor/human epidermal growth factor receptor 2 (ER/PR/HER2) status and axillary lymph node metastatic status for DCIS and their upgraded invasive counterparts can also provide diagnostic and therapeutic implications. We retrospectively studied 575 patients with first-time diagnosis of DCIS on biopsies, and followed up their final diagnosis, ER/PR/HER2 status, and axillary lymph node involvement on excisions. As a result, biopsy-diagnosed DCIS had an overall 19.1% risk to be upgraded on subsequent excisions, with 4.7% being upgraded to microinvasive carcinoma (pT1mi) and 14.4% to overt invasive carcinoma (⩾pT1a). Factors significantly associated with higher upgrading risk on multivariate analysis include biopsy guidance by ultrasound (P <.001), DCIS with suspicious microinvasion (P < .001), and DCIS diagnosed in left breast (P = .026). DCIS diagnosed in younger patients (⩽40 years old) or DCIS with high nuclear grade showed higher upgrading risk only on univariate analysis. About 80% ER + /PR + and ER-/PR- DCIS remained the same ER/PR status after being upgraded, and ER + /PR - DCIS had the highest risk (63.6%) of having HER2 amplification in upgraded invasive carcinoma. For upgraded DCIS, microinvasive carcinoma was more likely to have HER2 amplification (50%) than overt invasive carcinoma (29.5%). Besides, pure DCIS had a low risk of axillary lymph node macrometastasis (0.74%), while the risk increased in DCIS with microinvasion (4.4%) and was highest in overt invasive carcinoma (14.7%). The findings of this study are clinically relevant with respect to criteria that might be used in selecting patients for de-escalation trials.

Immunochemistry in the work-up of mesothelioma and its differential diagnosis and mimickers.

The differential diagnosis in cellular effusions with cytological atypia often includes malignant mesothelioma (MM), reactive mesothelial proliferation, and malignancies of metastatic origin, particularly carcinomas. The International Reporting System for Serous Fluid recently established guidelines for reporting MM. In conjunction with the cytomorphologic evaluation, the role of immunochemistry (IC) was emphasized as a very useful tool in the workup of serous fluids, especially with the availability of novel markers. Utilizing a panel of markers, IC allows the characterization of the cells, whether mesothelial or not, and when mesothelial origin is established, IC can frequently assist in delineating its benign or malignant nature. IC can also confirm metastatic disease, allowing the identification of the primary origin in most cases. This review summarizes the current status of IC and its role in the diagnosis of MM and its differential diagnosis in serous fluids.

Correlation between modified Magee equation-2 and Oncotype-Dx recurrence scores using both traditional and TAILORx cutoffs and the clinical application of the Magee Decision Algorithm: a single institutional review.

BACKGROUND: Oncotype Dx (ODX) is used to predict recurrence risk for estrogen-positive (ER +), HER2-negative and lymph node negative breast cancer, however, due to the cost its use may be limited in low-resource areas. The aim of this study is to assess the concordance between the modified Magee Equation-2 (MME-2) and ODX recurrence scores (RS). The secondary aim is to apply the Magee Decision Algorithm (MDA) using the MME-2 to determine which patients are unlikely to benefit from ODX testing. METHODS: All newly diagnosed ER + , HER2 negative, lymph node negative breast cancer patients with available ODX-RS from 2008-2018 were included. The original pathology reports were reviewed and chart review was performed. The MME-2 scores were calculated and correlated with the ODX-RS. The MDA was applied to our cohort to assess which patients would not benefit from ODX testing. RESULTS: A total of 579 patients were included. There was an overall moderate correlation between ODX-RS and MME-2 score (Pearson correlation coefficient = 0.635). The overall concordance between ODX and MME-2 scores was similar when using both the traditional and TAILORx cutoffs (63.3% vs. 63.7%, respectively). Applying the MDA, for patients with MME-2 scores < 18, 96.8% of patients had the expected ODX-RS of < 25. For patients with MME-2 RS > 30, 90% had the expected ODX-RS of > 25. Concordance was highest in the high-risk category using both cutoffs. For patients with MME-2 18-25 and a mitotic score of 1, 88.8% had the expected ODX-RS of > 25. CONCLUSION: There is a moderate correlation between MME-2 score and ODX-RS. The overall concordance was similar for both traditional and TAILORx cutoffs. The strongest concordance was found in the high-risk category for both cutoffs. The MME-2 can be used to identify patients unlikely to benefit from ODX testing using the MDA.

Adenoviral cytopathic changes in pleural fluid: A unique cytological presentation mimicking malignancy.

Adenoviruses are emerging as important viral pathogens in immunocompromised patients due to immunodeficiency diseases and recently hematopoietic stem cell and solid organ transplant recipients, impacting morbidity and even mortality. Immunocompromised children are prone to respiratory infection, due to alterations in their immune system. When confronted with diseases involving the pleural effusions, such as viral infections, the diagnostic problem becomes more complex and special effort is needed to recognize and characterize them accurately and to differentiate them from other pathologies such as malignancies. However, cytology of adenoviral infection in pleural effusions has not been reported before. We report a case of an adenovirus infection of the pleural effusion which included lymphocytosis associated with background atypical cells showing a cytopathic effect (cytoplasmic viral particles). The differential diagnosis included lymphoma and infections. Immunohistochemical stain for adenovirus was positive and confirmed by molecular studies. Usually in viral infections there are cytopathic changes due to viral particles affecting epithelial cells but this case is unique as the viral particles were identified in macrophages. We discuss the significance of such infection in comparison with other viral changes indigenous to the pleural effusions, which could also occur in such specimens.

Root cause analysis of indeterminate diagnoses in serous fluids cytopathology.

INTRODUCTION: The International System for Reporting Serous Fluid Cytopathology proposed five diagnostic categories: Nondiagnostic (ND), Negative for Malignancy (NFM), Atypia of Undetermined Significance (AUS), Suspicious for Malignancy (SFM) and Malignant (MAL) (Primary or Metastatic). The indeterminate (AUS/SFM) categories are challenging for management. The goal of this study is to reveal the root causes contributing to indeterminate diagnoses (ID). MATERIALS AND METHODS: We searched our archives between 1 January 2017 and 30 June 2019, and performed a root cause analysis (RCA) using the "5 whys" method to determine the contributing factors of ID. RESULTS: Nine hundred eleven specimens were evaluated and diagnosed: ND (9, 1%), NFM (667, 73.2%), AUS (51, 5.6%), SFM (27, 3%) and MAL (157, 17.2%). More than one factor contributed to 38/78 ID. Low volume (<50 cc), and low cellularity were identified in 31 and 51 cases, respectively. Three cases were simply deferred to concurrent biopsy. Eleven cases were called atypical, favor reactive mesothelium despite confirmatory IHC. Atypical lymphoid population was reported in seven cases. Cellblocks (CB) were low in cellularity despite volume >1000 mL in 13 cases. Two mesotheliomas were underdiagnosed as suspicious. CONCLUSIONS: Low cellularity and low volume were the most common contributing factors, highlighting the importance of adequate sample collection. Adequate volume specimens with low cellularity may benefit from a close inspection and a second CB. Some IDs can be switched to NFM or MAL with careful consideration of clinical, radiologic findings and ancillary testing, and concurrent surgical pathology correlation when available.