Diagnostic challenges in papillary lesions of the breast

Invasive papillary carcinoma of the breast: A case report

Invasive papillary carcinoma (IPC) of the breast is a rare form of cancer. The current report documents a case of IPC characterized by a large tumor size and skin involvement. Surgical exploration revealed no evidence of axillary lymph node metastasis in breast cancer. Due to financial constraints, the patient opted solely for anastrozole endocrine therapy at a dosage of 1 mg/day for a period of 5 years post-surgery, foregoing other treatments such as radiotherapy and chemotherapy. Since discharge, 2.5 years have passed, during which the patient has been followed up via phone every 3 months, showing a good prognosis. A literature review indicated that IPC is prevalent amongst the elderly population and can be misdiagnosed due to its morphological, cytomorphological and immunophenotypic overlap with other types of papillary neoplasms. This tumor exhibits a more favorable prognosis compared with IDC, primarily attributed to its advantageous gene and molecular expression patterns, coupled with its decreased invasiveness. Despite limited evidence-based research on the treatment of IPC, the present case report, albeit with limitations, underscores the importance of avoiding over-treatment and suggests the feasibility of combining surgery with endocrine therapy for IPC.

Invasive papillary carcinoma of the breast

Invasive papillary carcinoma is a rare form of breast cancer that is more likely to occur in postmenopausal women. Previous studies have been limited to case reports and small retrospective studies, leading to low awareness of this type of tumor and difficult clinical management. According to the available literature, invasive papillary carcinoma exhibits unique pathological features and biological behaviors. Invasive papillary carcinoma is mostly luminal type, with a low rate of lymph node metastasis, which underlies its favorable prognosis. The effectiveness of adjuvant therapy in reducing tumor burden and improving prognosis in patients with invasive papillary carcinoma remains uncertain. Due to the rarity of the lesion, conducting prospective clinical trials is impractical. The use of biological models, such as organoids, can help alleviate the impact of the scarcity of this condition on research. In addition, invasive papillary carcinoma is affected by specific genomic events, and more extensive studies of gene expression profiling may provide molecular-level insights to make optimal therapeutic decisions.

Differential Diagnosis of Benign and Malignant Breast Papillary Neoplasms on MRI With Non-mass Enhancement

RATIONALE AND OBJECTIVES

To explore the differential diagnosis of benign and malignant papillary neoplasms on MRI with non-mass enhancement.

MATERIALS AND METHODS

A total of 48 patients with surgically confirmed papillary neoplasms showing non-mass enhancement were included. Clinical findings, mammography and MRI features were retrospectively analyzed, and lesions were described according to the breast imaging report and data system (BI-RADS). Multivariate analysis of variance was used to compare the clinical and imaging features of benign and malignant lesions.

RESULTS

Fifty-three papillary neoplasms were shown on MR images with non-mass enhancement, including 33 intraductal papilloma and 20 papillary carcinomas (9 intraductal papillary carcinoma, 6 solid papillary carcinomas, and 5 invasive papillary carcinoma). Mammography showed amorphous calcification in 20% (6/30), of which 4 were in papilloma and 2 were in papillary carcinoma. On MRI, papilloma mostly showed linear distribution in 54.55% (18/33), clumped enhancement in 36.36% (12/33). Papillary carcinoma showed segmental distribution in 50% (10/20), clustered ring enhancement in 75% (15/20). ANOVA showed age (p = 0.025), clinical symptoms (p < 0.001), apparent diffusion coefficient (ADC) value (p = 0.026), distribution pattern (p = 0.029) and internal enhancement pattern (p < 0.001) were statistically significant between benign and malignant of papillary neoplasms. Multivariate analysis of variance suggested that the internal enhancement pattern was the only statistically significant factor (p = 0.010).

CONCLUSIONS

Papillary carcinoma on MRI with non-mass enhancement mostly showed internal clustered ring enhancement, while papilloma mostly showed internal clumped enhancement; additional mammography is of limited diagnostic value, and suspected calcification occurs mostly in papilloma.

Ultrasound-Guided Vacuum-Assisted Excision to Treat Intraductal Papilloma

BACKGROUND

To evaluate the value of ultrasound-guided vacuum-assisted excision (US-guided VAE) in the treatment of intraductal papillomas, including intraductal papillomas with atypical ductal hyperplasia (ADH), and to evaluate the lesion characteristic features affecting the local recurrence rate.

MATERIALS AND METHODS

Between August 2011 and December 2020, 91 lesions of 91 patients underwent US-guided VAE and were diagnosed with intraductal papilloma with or without ADH. The recurrence rate of intraductal papilloma was evaluated on follow-up US. The lesion characteristic features were analyzed to identify the factors affecting the local recurrence rate.

RESULTS

The local recurrence rate of intraductal papillomas removed by US-guided VAE was 7.7% (7/91), with the follow-up duration 12-92 months (37.4 ± 23.9 months). Of the 91 patients, five cases diagnosed as intraductal papilloma with ADH did not recur, with the follow-up time 12-47 months (26.4 ± 14.4 months). There were no malignant transformation in all 91 cases during the follow-up period. All 7 patients recurred 7-58 months (22.8 ± 19.2 months) after US-guided VAE. There were no significant differences between the non-recurrence and recurrence groups in terms of age, side, distance from nipple, lesion size, BI-RADS category, with ADH, or history of excision (p > 0.05).

CONCLUSIONS

US-guided VAE is an effective method for the treatment of intraductal papilloma, including intraductal papilloma with ADH. It avoids invasive surgical excision, but regular follow-up is recommended to prevent recurrence or new onset due to multifocality. Any suspicious lesions during the follow-up should be actively treated.

Rat Mammary carcinoma susceptibility 3 (Mcs3) pleiotropy, socioenvironmental interaction, and comparative genomics with orthologous human 15q25.1-25.2

Genome-wide association studies of breast cancer susceptibility have revealed risk-associated genetic variants and nominated candidate genes; however, the identification of causal variants and genes is often undetermined by genome-wide association studies. Comparative genomics, utilizing Rattus norvegicus strains differing in susceptibility to mammary tumor development, is a complimentary approach to identify breast cancer susceptibility genes. Mammary carcinoma susceptibility 3 (Mcs3) is a Copenhagen (COP/NHsd) allele that confers resistance to mammary carcinomas when introgressed into a mammary carcinoma susceptible Wistar Furth (WF/NHsd) genome. Here, Mcs3 was positionally mapped to a 7.2-Mb region of RNO1 spanning rs8149408 to rs107402736 (chr1:143700228-150929594, build 6.0/rn6) using WF.COP congenic strains and 7,12-dimethylbenz(a)anthracene-induced mammary carcinogenesis. Male and female WF.COP-Mcs3 rats had significantly lower body mass compared to the Wistar Furth strain. The effect on female body mass was observed only when females were raised in the absence of males indicating a socioenvironmental interaction. Furthermore, female WF.COP-Mcs3 rats, raised in the absence of males, did not develop enhanced lobuloalveolar morphologies compared to those observed in the Wistar Furth strain. Human 15q25.1-25.2 was determined to be orthologous to rat Mcs3 (chr15:80005820-82285404 and chr15:83134545-84130720, build GRCh38/hg38). A public database search of 15q25.1-25.2 revealed genome-wide significant and nominally significant associations for body mass traits and breast cancer risk. These results support the existence of a breast cancer risk-associated allele at human 15q25.1-25.2 and warrant ultrafine mapping of rat Mcs3 and human 15q25.1-25.2 to discover novel causal genes and variants.

Papillary lesions of the breast - review and practical issues

Papillary lesions of the breast represent a heterogeneous group of neoplasm featuring fibrovascular cores covered by epithelial cells with or without intervening myoepithelial cells. According to the World Health Organization classification of breast tumors, papillary lesions of the breast are further classified into intraductal papilloma (including intraductal papilloma with atypical ductal hyperplasia /ductal carcinoma in situ), papillary ductal carcinoma in situ, encapsulated papillary carcinoma, solid papillary carcinoma (in situ and invasive) and invasive papillary carcinoma. The overlapping morphological features and immunohistochemical profiles make accurate diagnosis of breast papillary lesion a challenge for pathologists. In this review, the morphological and relevant immunohistochemical features of papillary lesions are discussed, with further emphasis on some commonly encountered practical diagnostic issues. A simple diagnostic algorithm will be established. The relevant molecular characteristics will be discussed as well.

Factors associated with upgrade, malignant upgrade, and subsequent breast cancer occurrence of papillary breast lesions diagnosed on core needle biopsy

AIM

In this study, we analyzed the upgrade rate and associated factors for upgrade, malignant upgrade, and subsequent breast cancer occurrence of papillary breast lesions diagnosed on core needle biopsy (CNB).

METHODS

One hundred sixty-nine patients who underwent surgery for the treatment of papillary breast lesions diagnosed on CNB were included in this study. Medical records including radiological and pathological reports were retrospectively reviewed.

RESULTS

The overall upgrade rate was 29.6%, and upgrade rate to malignancy was 16.6%. Age over 45 years, preoperative tumor size ≥0.7 cm on breast ultrasound, pathologic tumor size ≥0.4 cm, breast imaging reporting and data system (BIRADS) category 4b or 4c, and personal history of breast cancer were associated with upgrade. In addition, age over 45 years, preoperative tumor size ≥0.9 cm, pathologic tumor size ≥0.6 cm, atypia in CNB, and BIRADS category 4b or 4c were associated with malignancy. The risk of subsequent breast cancer occurrence was increased in preoperative tumor size ≥0.8 cm, pathologic tumor size ≥0.5 cm, multiple and recurrent lesions.

CONCLUSION

Our study showed high upgrade rate of papillary breast lesions diagnosed on CNB. Our findings suggest that surgical excision is recommended for papillary breast lesions diagnosed on CNB in selected patients.

Papillary lesions of the breast

Papillary lesions of the breast represent a heterogeneous group of lesions including benign papillomas, papillomas with focal epithelial atypia, fully fledged ductal carcinoma in situ (DCIS) or lobular neoplasia, papillary DCIS, encapsulated papillary carcinomas without or with invasion, solid papillary carcinomas, and invasive papillary carcinomas. A micropapillary pattern characterized by lack of fibrous stalks within the papillae is observed in micropapillary DCIS and invasive micropapillary carcinoma. In addition, a variety of other rare breast lesions reveals a papillary architecture such as tall cell carcinoma with reversed polarity (TCCRP) and mucinous cystadenocarcinoma, adenomyoepithelioma, and secretory carcinoma. In addition, benign lesions such as usual ductal hyperplasia, apocrine metaplasia, gynecomastia, and juvenile papillomatosis may show a papillary or micropapillary architecture. Fragments of a benign papilloma in a breast biopsy are considered a lesion of uncertain malignant potential (B3 in the European classification) and excision is mostly recommended. Although the knowledge about molecular pathology of papillary breast lesions has increased, there is not sufficient evidence for diagnostically useful molecular features, yet. The aim of this review is to provide an update on papillary and micropapillary lesions with emphasis on problematic areas for daily diagnostic work including biopsies.

Detailed Morphologic Evaluation of Breast Papillary Lesions on Core Biopsy Is Critical for Accurate Classification and Clinical Management: The Experience of an Academic Institute

BACKGROUND

Distinguishing between a breast intraductal papilloma and a papillary lesion with atypia or malignancy can be very challenging on core biopsy. There has been a long ongoing debate over whether or not it is necessary for breast papillary lesions diagnosed on core biopsies to be surgically excised, and the upgrading rate after excision varies.

METHOD AND/OR RESULT

This study was carried out in a subspecialized academic pathology department, with well-formed criteria established among the faculty for the categorization of breast papillary lesions, with emphasis on the morphology evaluation of cellular features. A total of 320 breast core biopsies with follow-up excisions were identified. Of these, 286 cases had concordant results between the biopsy and excision, giving a concordance rate of 89.4%, with 98% concordance (143/146) in benign papilloma, 100% (111/111) in papillary carcinoma, and 51% (32/63) in papilloma with atypia. Of the upgraded cases, two were upgraded from benign to atypical, 11 from atypia to malignancy, and only one from benign to malignant. The overall average upgrading rate was 4.4% (14/320), with the critical upgrading (from benign to atypia or malignancy) rate of 0.94% (3/320). Downgrading was only identified in the group of papilloma with atypia, with 20 of 63 cases downgraded to benign papilloma on excision.

CONCLUSION

Our study indicates that surgical excision may not be necessary for all papillary lesions after detailed evaluation of the morphology on core biopsies. Assessing the morphological features of the epithelial cells is critical for the accurate classification and clinical management of papillary lesions.

Rare Papillary Breast Carcinoma Incidentally Discovered After Trauma-Induced Hematoma

Papillary carcinoma of the breast is rare, comprising only 0.5% incidence of all breast cancers. Clinically the disease presents in postmenopausal women as a painless breast lump with possible bloody nipple discharge. Prognosis is favorable due to its slow growth. We present a 61-year-old woman incidentally diagnosed with papillary breast carcinoma after presenting with a trauma-induced hematoma of the right breast. The patient presented to our surgery oncology clinic for persistent right breast swelling secondary to a fall, despite initial incision and drainage (I&D) six weeks prior. She had no history of breast cancer. On presentation, her right breast was distended demonstrating an approximately 20cm ill-defined solid mass with skin changes consistent with a tense hematoma. CT scan demonstrated a large complex cystic and solid breast mass measuring 15.2cmx11.8cmx15.2cm with irregular peripheral solid hyperdense polypoid components. She then underwent a right breast incisional biopsy and hematoma evacuation. Frozen sections of the mass outer cavity wall and papillary projections were consistent with encapsulated papillary carcinoma (EPC). The patient was lost to follow-up and did not obtain definitive treatment. Breast cancer rarely presents as a breast hematoma. However, as in this case, if the hematoma fails to resolve, further investigation is warranted. The prognosis of EPC is excellent when identified and treated appropriately.

A multicenter study of interobserver variability in pathologic diagnosis of papillary breast lesions on core needle biopsy with WHO classification

BACKGROUND

Papillary breast lesions (PBLs) comprise diverse entities from benign and atypical lesions to malignant tumors. Although PBLs are characterized by a papillary growth pattern, it is challenging to achieve high diagnostic accuracy and reproducibility. Thus, we investigated the diagnostic reproducibility of PBLs in core needle biopsy (CNB) specimens with World Health Organization (WHO) classification.

METHODS

Diagnostic reproducibility was assessed using interobserver variability (kappa value, κ) and agreement rate in the pathologic diagnosis of 60 PBL cases on CNB among 20 breast pathologists affiliated with 20 medical institutions in Korea. This analysis was performed using hematoxylin and eosin (H&E) staining and immunohistochemical (IHC) staining for cytokeratin 5 (CK5) and p63. The pathologic diagnosis of PBLs was based on WHO classification, which was used to establish simple classifications (4-tier, 3-tier, and 2-tier).

RESULTS

On WHO classification, H&E staining exhibited 'fair agreement' (κ = 0.21) with a 47.0% agreement rate. Simple classifications presented improvement in interobserver variability and agreement rate. IHC staining increased the kappa value and agreement rate in all the classifications. Despite IHC staining, the encapsulated/solid papillary carcinoma (EPC/SPC) subgroup (κ = 0.16) exhibited lower agreement compared to the non-EPC/SPC subgroup (κ = 0.35) with WHO classification, which was similar to the results of any other classification systems.

CONCLUSIONS

Although the use of IHC staining for CK5 and p63 increased the diagnostic agreement of PBLs in CNB specimens, WHO classification exhibited a higher discordance rate compared to any other classifications. Therefore, this result warrants further intensive consensus studies to improve the diagnostic reproducibility of PBLs with WHO classification.

A multicenter study of interobserver variability in pathologic diagnosis of papillary breast lesions on core needle biopsy with WHO classification

Background

Papillary breast lesions (PBLs) comprise diverse entities from benign and atypical lesions to malignant tumors. Although PBLs are characterized by a papillary growth pattern, it is challenging to achieve high diagnostic accuracy and reproducibility. Thus, we investigated the diagnostic reproducibility of PBLs in core needle biopsy (CNB) specimens with World Health Organization (WHO) classification.

Methods

Diagnostic reproducibility was assessed using interobserver variability (kappa value, κ) and agreement rate in the pathologic diagnosis of 60 PBL cases on CNB among 20 breast pathologists affiliated with 20 medical institutions in Korea. This analysis was performed using hematoxylin and eosin (H&E) staining and immunohistochemical (IHC) staining for cytokeratin 5 (CK5) and p63. The pathologic diagnosis of PBLs was based on WHO classification, which was used to establish simple classifications (4-tier, 3-tier, and 2-tier).

Results

On WHO classification, H&E staining exhibited ‘fair agreement’ (κ = 0.21) with a 47.0% agreement rate. Simple classifications presented improvement in interobserver variability and agreement rate. IHC staining increased the kappa value and agreement rate in all the classifications. Despite IHC staining, the encapsulated/solid papillary carcinoma (EPC/SPC) subgroup (κ = 0.16) exhibited lower agreement compared to the non-EPC/SPC subgroup (κ = 0.35) with WHO classification, which was similar to the results of any other classification systems.

Conclusions

Although the use of IHC staining for CK5 and p63 increased the diagnostic agreement of PBLs in CNB specimens, WHO classification exhibited a higher discordance rate compared to any other classifications. Therefore, this result warrants further intensive consensus studies to improve the diagnostic reproducibility of PBLs with WHO classification.

Papillary Breast Tumors: Continuing Controversies and Commentary on WHO's 2019 Criteria and Classification

The category of papillary breast tumors includes a limited number of entities. Nonetheless, this relatively uncommon group of tumors seems to instigate a disproportionate degree of diagnostic disquiet. As a group, papillary breast tumors suffer from a relatively high rate of discordant interpretation. The latter is due to the inherent complexity of the lesions compounded by conflicting criteria as well as simmering controversies. For instance, "encapsulated" papillary carcinoma remains contentious with regards to whether these are noninvasive or not, and the assessment of the extent of the invasive versus noninvasive components in many solid papillary carcinomas can be problematic. The latest classification system of breast tumors enunciated by the World Health Organization (WHO), that is, Breast Tumors, which appeared in 2019, mainly sought to incorporate advances in basic and clinical sciences into diagnostic criteria for the entire spectrum of breast neoplasms-including papillary ones. The latter category of tumors is discussed at some length in Breast Tumors; however, it still appears to suffer from some lack of clarity in its subclassification. It is our intent in this communication to provide an overview of the controversies around papillary breast tumors, and offer comments on its coverage in Breast Tumors-so that any tangible or perceived ambiguities therein could be addressed in its next edition.

Noninvasive discrimination of benign and malignant breast lesions using genome-wide nucleosome profiles of plasma cell-free DNA

BACKGROUND

Breast malignancy is the most frequently diagnosed malignancy in women worldwide, and the diagnosis relies on invasive examinations. However, most clinical breast changes in women are benign, and invasive diagnostic approaches cause unnecessary suffering for the patients. Thus, a novel noninvasive approach for discriminating malignant breast lesions from benign lesions is needed.

METHODS

We performed cell-free DNA (cfDNA) sequencing on plasma samples from 173 malignant breast lesion patients, 158 benign breast lesion patients, and 102 healthy women. We then analyzed the cfDNA-based nucleosome profiles, which reflect the various tissues of origin and transcription factor activities. Moreover, by using machine learning classifiers along with the cfDNA sequencing data, we built classifiers for discriminating benign from malignant breast lesions. Receiver operating characteristic curve analyses were used to evaluate the performance of the classifiers.

RESULTS

cfDNA-based nucleosome profiles reflected the various tissues of origin and transcription factor activities in benign and malignant breast lesions. The cfDNA-based transcription factor activities and breast malignancy-specific transcription factor-binding site accessibility profiles could accurately distinguish benign and malignant breast lesions, with area under the curve values of 0.777 and 0.824, respectively.

CONCLUSIONS

Our proof-of-principle study established a methodology for noninvasively discriminating benign from malignant breast lesions.

Artefactual Epithelial Displacement in a Papilloma with Extensive Usual Duct Hyperplasia Mimics a Solid Papillary Carcinoma with Invasive Growth

Mammary solid papillary carcinoma and usual duct hyperplasia (UDH) of the breast are morphological look-alikes, characterized by cellular streaming, solid growth, and a lack of high-grade nuclear atypia. Here, we report a challenging papillary lesion in the breast of a 48-year-old woman that presented with a double pitfall. A core needle biopsy showed a solid papillary proliferation of epithelial cells with oval to round overlapping nuclei, surrounded by a sclerotic stroma. This distorted lesion contained peripheral clefts and cellular streaming, without high-grade nuclear atypia. Immunohistochemistry showed diffuse heterogenous immunoreactivity for estrogen receptor and cytokeratin 5, and no immunoreactivity for chromogranin and synaptophysin. The immunohistochemical profile distinguished this sclerosed papilloma with extensive UDH from a solid papillary carcinoma. The lumpectomy specimen revealed a second challenge, where multiple epithelial islets without surrounding myoepithelial cells were observed near the papilloma, mimicking an invasive carcinoma. These islets displayed the same immunohistochemical profile as the sclerosed papilloma and they were surrounded by steatonecrosis and reactive fibroblasts, indicating epithelial displacement within the biopsy needle tract. A sclerosed papilloma with extensive UDH is a morphologically challenging mimic of a solid papillary carcinoma. Immunohistochemistry is helpful to distinguish both entities from one another. Extensive epithelial displacement in the biopsy tract made this case particularly challenging, as the displaced epithelial islets mimicked an invasive carcinoma. Pathologists should be aware of this uncommon double pitfall to prevent misdiagnosis.

Papillary lesions of the breast: A systematic evaluation of cytologic parameters

BACKGROUND

The cytologic diagnosis of papillary lesions of the breast is challenging because of the diverse morphology, including epithelial hyperplasia, atypia, low-grade malignancy, and neuroendocrine differentiation; also, traditional malignant features such as necrosis and myoepithelial cell loss can be lacking. Thus, the diagnostic criteria for papillary lesions may differ from those for other breast lesions. This study evaluated various cytologic parameters in a large cohort to identify useful diagnostic features.

METHODS

Cytologic preparations of papillary lesions with histologic follow-up were reviewed for features related to cellularity, epithelial cohesiveness, cellular and stromal architecture, cytomorphology, and background. Corresponding histologic slides were also reviewed.

RESULTS

In all, 153 cases were included. Epithelial discohesion, solid and cribriform patterns, atypical nuclear features, and mitoses (P ≤ .001 to P = .017) were associated with malignancy. Cell balls, monolayer sheets, and features of cystic change (P < .001 to P = .016) were associated with benign lesions. Complex (P = .031) and slender (P = .026) papillae and neuroendocrine features (P < .001) were associated with malignancy. Hemorrhage, background, and infiltrating neutrophils (P < .001 to P = .025) were associated with malignancy; fibrotic broad papillary stromal fragments (naked papillary fronds [NPFs]; P = .043) were associated with benignity. The presence of any single parameter, including the absence of myoepithelial cells within epithelial structure, the presence of cytoplasmic granules, an increased amount of cytoplasm, and a nuclear to cytoplasmic (N/C) ratio greater than 0.7, which were identified by principal component analysis, yielded a sensitivity of 95.1% and a specificity of 100.0% in predicting malignancy.

CONCLUSIONS

Methodological assessment of multiple features is recommended. Myoepithelial cells, cytoplasmic granules, the amount of cytoplasm, and the N/C ratio are key features for diagnosis.

Papillary lesions of the breast: a review

Papillary breast lesions are rare breast tumors that comprise a broad spectrum of diseases. Pathologically they present as mass-like projections attached to the wall of the ducts, supported by fibrovascular stalks lined by epithelial cells. On mammogram they appear as masses that can be associated with microcalcifications. Ultrasound is the most used imaging modality. On ultrasound papillary lesions appear as homogeneous solid lesions or complex intracystic lesions. A nonparallel orientation, an echogenic halo or posterior acoustic enhancement associated with microcalcifications are highly suggestive of malignancy. MRI has proven to be useful to establish the extent of the lesion. Core needle biopsy is the gold standard for diagnosis. Surgical excision is usually recommended, although treatment for papillomas without atypia is still controversial.

Mixed Invasive Apocrine Papillary/Micropapillary Carcinoma of the Breast: Another Brick in the Triple-Negative Wall

Pure invasive papillary carcinoma (IPC) is a rare subtype of breast carcinoma with good prognosis compared with classical invasive breast carcinoma (IBC) of no special type. The majority of IPC are estrogen receptor and progesterone receptor (ER/PR) positive and HER2 negative (luminal A-like). We report the case of a 72-year-old women who was referred to the Senology Clinic for a routine workup following surgery for an intraductal papilloma. The core needle biopsy (CNB) showed a lesion mainly composed of irregular papillae and micropapillae with apocrine epithelial cells of low-to-intermediate nuclear grade, without a myoepithelial cell layer within the papillae and at the periphery, as demonstrated with multiple immunostains. The diagnosis of apocrine papillary lesion of uncertain malignant potential was made. The subsequent lumpectomy showed an IBC with the same cyto-architectural features as the CNB. In addition, lymphovascular invasion and papillary/micropapillary apocrine in situ lesion were noted. Notably, the tumor was ER/PR and HER2 negative and strongly positive for androgen receptor. A final diagnosis of mixed apocrine papillary/micropapillary carcinoma with triple-negative status was made. To the best of our knowledge, this is the first report of an IBC with these features. Breast pathologists should be aware of this entity when dealing with CNB samples characterized by a complex papillary lesion with apocrine atypia that lacks a myoepithelial cell layer on multiple immunostains. These lesions should be classified at least as of uncertain malignant potential based on the cyto-architectural features prompting a surgery for removal.

Encapsulated papillary carcinoma of breast; a clinicopathological study of 25 cases and literature review with emphasis on high grade variant

Encapsulated Papillary Carcinoma (EPC) is a rare breast tumor with excellent prognosis. Treatment and stage of EPC is influenced by invasion and high nuclear grade. Our aim was to study the clinicopathological features of EPC, especially high grade tumors and to compare the features of invasive and non-invasive tumors. We reviewed clinicopathological features of 25 cases of EPC diagnosed at our institution from 2006 till 2020. Patients' age ranged from 21 to 75 years (median 55 years). Tumor size ranged from 1 to 9 cm (median 3.5 cm). Overall, invasion was present in 44% cases. High nuclear grade was observed in 24% cases. Majority of these high grade tumors were below 40 years. All of these tumors were 4 cm or larger in size. Two third of these tumors were invasive. Hormone receptor negativity and lymph node involvement was observed in 1 out of 3 cases, when performed. Clinicopathological and histological features of invasive and non-invasive tumors were compared and only lymph node involvement was found to be significantly more frequent in invasive tumors (p = 0.049). Median follow up duration was 18 months. All patients were alive and disease free except for a single patient who died of cerebrovascular accident. EPC has excellent clinical course. Invasion and high nuclear grade should be carefully searched for as these features determine tumor stage and treatment.

A retrospective observational study of intraductal breast papilloma and its coexisting lesions: A real-world experience

Background

Breast intraductal papilloma is a heterogeneous group. The aim of the study is to investigate the intraductal breast papilloma and its coexisting lesions retrospectively in real‐world practice.

Methods

We retrospectively identified 4450 intraductal breast papilloma and its coexisting lesions.

Results

About 18.36% of intraductal papilloma coexisted with malignant lesions of the breast, 37.33% coexisted with atypia hyperplasia (AH), 25.24% coexisted with benign lesions, and only 19.10% coexisted without concomitant lesions. In addition, 36.80% of intraductal breast papilloma had nipple discharge, 51.46% had a palpable breast mass, and 16.45% had both nipple discharge and a palpable breast mass. About 28.18% experienced discomfort or were asymptomatic. Furthermore, 98.99% had ultrasound abnormalities, and 53.06% had intraductal hypoechogenicity upon ultrasound. 31.89% had mammographic distortion, and 14.45% had microcalcification upon mammography. Intraductal breast papilloma with malignancy had significant correlations with clinical manifestations.

Conclusion

Coexisting malignancy was also related to ultrasound abnormality (BIRADS 4C and 5), mammographic distortion, and microcalcification upon mammography but was not related to the intraductal hypoechoic upon ultrasound. Coexisting atypical hyperplasia correlated with nipple discharge but not palpable mass, mammographic distortion, or intraductal hypoechoic upon ultrasound. The coexisting AH was also related to abnormality upon ultrasound or microcalcification compared with the benign lesions. The intraductal papilloma coexists with malignancy or AH accounted for more than 50%, and the clinical information on papilloma and its coexisting lesions is nonspecific. We recommended surgical treatment for benign intraductal papillary lesions.

Tall cell carcinoma of the breast with reversed polarity (TCCRP) with mutations in the IDH2 and PIK3CA genes: a case report

Tall cell carcinoma with reversed polarity (TCCRP) is a rare breast carcinoma with low malignant potential, initially named "breast tumor resembling the tall cell variant of papillary thyroid carcinoma", which has recently been recognized as a separate entity in the 5th edition of the WHO (World Health Organization) classification of breast tumors. Since the first report of this entity in 2003, more than 40 cases have been reported in the literature. Here, we report another case of this rare tumor in a 60-year-old woman. We performed immunohistochemical analyses and next-generation-sequencing (NGS) using the Oncomine™ Comprehensive DNA Panel (Thermo Fisher Scientific). The tumor showed the typical morphological features of TCCRP and a "triple-negative" phenotype. Moreover, we identified pathogenic mutations in the IDH2 (p.R172G) and PIK3CA (p.H1047R) genes. We report a case of TCCRP of the breast showing the characteristic morphologic, immunohistochemical and molecular features of this entity. There is still a limited number of cases with comprehensive molecular analyses reported in the literature. Therefore, we herewith contribute to a better understanding of the morphological and molecular characteristics as well as the clinical behavior of this rare entity.

Apparent diffusion coefficient value in breast papillary lesions without atypia at core needle biopsy

PURPOSE

The main aim of the study was to assess if the mean apparent diffusion coefficient (ADC) value was significantly different between papillary lesions (PL) without atypia and PLs with atypical or malignant foci. A secondary objective was to evaluate if patients mean age, MRI BI-RADS® descriptors and assessment category were significantly different between these two PL groups.

METHODS

In this eight year retrospective study were included 122 patients (mean age, 51 years; range, 24-78) with 122 PLs without atypia at micro-histological examination after core needle biopsy (CNB) performed under sonographic guidance. All patients underwent surgical excision biopsy within 3 months after CNB. All patients underwent MRI examination before surgical excision, including STIR, DWI and Dynamic Contrast-Enhanced sequences.

RESULTS

Mean ADC value difference between PLs without and with atypia or malignant foci was statistically significant (p < 0.0001). Mean ADC value optimal threshold in order to distinguish the two groups was 1.418 × 10^-3 mm²/s. A mean ADC value ≤ 1.418 × 10^-3 mm²/s could predict atypical or malignant foci within a PL with 83.9% sensitivity and 75.8% specificity. No statistically significant difference was found with regard to patients mean age, MRI BI-RADS® descriptors and assessment category between these two PL groups.

CONCLUSIONS

Mean ADC value of PLs without atypia at CNB is an efficient tool in order to help distinguish between PLs without and with atypical or malignant foci at final pathology on surgical excision, and it could be used to help decide how to manage these lesions.

Rare epithelial breast cancer: surgery and adjuvant therapy

Breast cancer is a heterogenous disease, exhibiting a wide range of morphological phenotypes shaping its prognosis and clinical course. However, optimal management of rarer breast cancer subtypes is often undefined and controversial in literature due to the lack of large studies and randomised trials. This review aims to discuss the treatment of 13 rare epithelial subtypes, focussing on surgery and adjuvant therapies.

Immunohistochemistry for diagnosis and prognosis of breast cancer: a review

Breast cancer is the most prevalent malignant tumor and main oncologic cause of mortality in women. Although most diagnosis of breast pathology is accomplished using hematoxylin and eosin stained sections, some cases require immunohistochemistry for proper evaluation. We investigated the latter cases including distinctions between ductal and lobular carcinoma, in situ and invasive carcinoma, typical ductal hyperplasia and atypical ductal hyperplasia/ductal carcinoma in situ, papillary and spindle cell lesion assessment, metastasis evaluation, and assessment of prognostic and therapy markers. E-cadherin is used to differentiate ductal and lobular carcinoma; 34βE12, CK8, p120 catenin and β-catenin also produce consistent results. Myoepithelial cell (MEC) stains are used to evaluate in situ and invasive carcinoma; calponin, smooth muscle myosin heavy chain and p63 are sensitive/specific markers. 34βE12 and CK5/6 are positive in ductal hyperplasia, which enables its differentiation from atypical ductal hyperplasia and ductal carcinoma in situ. CK 5/6, ER and MEC markers are consistent options for evaluating papillary lesions. Spindle cell lesions can be assessed using β-catenin, SMA, CD34, p63, CKs and hormone receptors. It is important to differentiate primary carcinomas from metastases; the most commonly used markers to identify breast origin include mammaglobin, GCDFP-15, GATA3 and ER, although none of these is completely sensitive or specific. Immunohistochemistry can be used to evaluate central prognostic and predictive factors including molecular subtypes, HER2, hormone receptors, proliferation markers (Ki-67) and lymph-vascular invasion markers including ERG, CD31, CD34, factor VIII and podoplanin. Owing to the complexity of mammary lesions, diagnosis also depends on each particular situation, evaluation of cytological characteristics revealed by immunochemistry and correlation with histological findings.

Apocrine papillary lesion: comparison of pathological findings from 22 years previously and the present

Apocrine papillary lesion (APL) is difficult to diagnose as benign or malignant. We experienced an APL remaining in the body for 22 years. We present a case of a 71-year-old woman who had undergone excisional biopsy 22 years previously at the first hospital that she visited. 1 year previously, she had undergone fine-needle aspiration cytology at a second hospital, and the lesion was diagnosed as potentially malignant. She underwent core-needle biopsy at a third hospital, but whether the lesion was benign or malignant could not be definitively diagnosed. We performed right mastectomy and sentinel lymph-node biopsy, because her tumor was suspected to be malignant based on imaging means, and malignancy could not be ruled out on either biopsy or cytology. The histopathological diagnosis was tiny foci of apocrine proliferative lesion with massive hemorrhagic necrosis and no tumor metastasis in two sentinel lymph nodes. Retrospectively, we compared all of the patient's previous specimens with the present ones, and applied the recent pathological diagnostic criteria. Although the biopsy specimen excised 22 years ago suggested an encapsulated apocrine papillary carcinoma or a papilloma with apocrine ductal carcinoma in situ, neither infiltration nor metastasis has occurred. Furthermore, neither the pathological findings nor the clinical behavior has changed over time.