Adenoid cystic carcinoma of the breast in the United States (1977 to 2006): a population-based cohort study

MYB expression by immunohistochemistry is highly specific and sensitive for detection of solid variant of adenoid cystic carcinoma of the breast among all triple-negative breast cancers

BACKGROUND

Adenoid cystic carcinoma is a rare subtype of triple-negative breast carcinoma. These low-grade tumours, which are treated by simple mastectomy and have an excellent prognosis compared to other triple-negative breast carcinomas. Solid-variant adenoid cystic carcinomas have basaloid features and are difficult to distinguish morphologically from other triple-negative breast cancers. Breast adenoid cystic carcinoma exhibits MYB protein overexpression, which can be detected by immunohistochemistry (IHC).

AIM

We compared the IHC expression of MYB in solid-variant adenoid cystic carcinoma with that in other triple-negative breast cancers.

METHODS

We conducted IHC staining of 210 samples of triple-negative breast cancers, including solid-variant adenoid cystic carcinoma (n = 17), metaplastic breast carcinoma (n = 44), basaloid triple-negative breast cancer (n = 21), and other triple-negative invasive ductal carcinoma (n = 128). We classified nuclear staining of MYB as diffuse/strong (3+), focal moderate (2+), focal weak (1+), or none (0).

RESULTS

All 17 solid/basaloid adenoid cystic carcinoma cases exhibited 3+ MYB expression. Of the 21 solid/basaloid triple-negative breast cancers, one (5%) had 2+ expression, seven (33%) 1+ expression, and 13 (62%) 0 expression. Of the 44 metaplastic carcinoma cases, 39 cases (89%) had no (0) staining, and the other five cases had focal weak (1+) or moderate (2+) staining. Among the 128 triple-negative invasive ductal carcinoma cases, 92 cases (72%) had no (0) staining, 36 cases (28%) exhibited focal weak (1+) or moderate (2+) staining.

CONCLUSIONS

Our study revealed diffuse/strong MYB staining (3+) only in solid/basaloid adenoid cystic carcinomas. Thus, we recommend routine MYB IHC staining in triple-negative breast carcinoma with solid/basaloid morphology to improve diagnostic accuracy.

Immunohistochemical marker profiles for the differentiation of collagenous spherulosis from adenoid cystic carcinoma of the breast

Collagenous spherulosis (CS) is a rare breast lesion of unknown histogenesis. Adenoid cystic carcinoma (ACC) is a rare basal-like breast carcinoma with low histological grade. CS is a benign lesion but resembles ACC. Both lesions show a similar histomorphology and feature bilineage differentiation. This study compared immunohistochemical markers in CS and ACC. We compiled n = 13 CS cases and n = 18 mammary ACCs. Fourteen marker proteins (ER, PR, HER2, GATA3, CK7, E-cadherin, CD117, CK5/14, p40, p63, SMA, CD10, calponin, P-cadherin) were evaluated by immunohistochemistry (IHC). MYB rearrangement, a common alteration in ACC, was assessed by fluorescence in situ hybridization. Patient age ranged between 40-60 years for CS lesions and 30-90 years for ACCs. 7/13 (54%) CS cases harbored a lobular carcinoma in situ (LCIS) in the luminal component. One CS/LCIS lesion occurred in a carrier of a pathogenic germline variant in CDH1/E-cadherin. MYB rearrangement was detected in 0/11 (0%) CS and 6/16 (37%) ACC cases (P = 0.054). CS was associated with expression of ER in the luminal component (P < 0.001), E-cadherin loss in the luminal component (P = 0.045), and expression of CD10 and calponin in the basal component (P < 0.001). Furthermore, CS was associated with GATA3 expression in the luminal component (12/13 [92%] versus 5/18 [27%], P < 0.001). In summary, IHC for GATA3 and E-cadherin may contribute to the differential diagnosis between CS and ACC, although these markers are not exclusively expressed in either lesion. Histologic evaluation has to take into account that CS is frequently colonized by LCIS, requiring thorough correlation of histomorphology and immunohistochemical features.

Solid basal adenoid cystic carcinoma of the breast: A case report and literature review

RATIONALE

Adenoid cystic carcinoma (AdCC) is a rare malignancy of the breast with a low Ki-67 index and good prognosis. Owing to the rarity of breast AdCC, the misdiagnosis rate is as high as 50%, and there is no consensus or recognized guidelines for the treatment of this disease. Therefore, it is necessary to conduct a detailed clinical and pathological analysis in combination with a literature review to improve our understanding, diagnosis, and treatment of the disease.

METHODS

A 68-year-old woman sought medical attention due to a recently increasing mass in the breast. The left breast mass was 1.3 cm × 1 cm in size. We analyzed the morphology, immunohistochemistry, and molecular characteristics of the tumor removed by surgery, and reviewed relevant literature.

DIAGNOSES

Solid basal AdCC of the breast.

INTERVENTIONS

We performed biopsy, immunohistochemistry and molecular testing on surgical resection specimens.

OUTCOMES

Combining morphological and immunohistochemical features, it is consistent with solid basal AdCC of the breast, and Fish detected MYB gene break.

LESSONS

Due to the high misdiagnosis rate of AdCC, accurate histopathological diagnosis is particularly important. At present, breast conserving surgery and local tumor resection are mainly used for the treatment of breast AdCC, and postoperative adjuvant radiotherapy is feasible.

High-grade HER2-positive mucoepidermoid carcinoma of the breast: a case report and review of the literature

BACKGROUND

Mucoepidermoid carcinoma of the breast is a rare special type of salivary gland-like tumor of the breast, usually displaying triple-negative phenotype. To date, only 64 cases have been reported in the English literature. Herein, we report the first case of mucoepidermoid carcinoma of the breast with human epidermal growth factor receptor 2 gene amplification.

CASE PRESENTATION

A 58-year-old Caucasian woman treated with breast-conserving surgery, radiotherapy, and chemotherapy for an invasive breast carcinoma of no special type, relapsed 20 years later in the ipsilateral left breast. Histological examination of the core needle biopsy of the relapse deferred to the surgical specimen for the definitive diagnosis, because of the broad differential diagnosis. On the resected specimen we observed the presence of a poorly differentiated carcinoma with mucoepidermoid carcinoma of the breast typical features consisting of epidermoid, intermediate and mucinous cells lacking true keratinization, in keeping with the latest World Health Organization diagnostic criteria. The mucoepidermoid carcinoma of the breast was weakly estrogen receptor and androgen receptor positive and progesterone receptor negative, but exceptionally showed human epidermal growth factor receptor 2 gene amplification. Mastermind-like transcriptional coactivator 2 gene translocations were not detected by fluorescent in situ hybridization. The patient received adjuvant chemotherapy with anti-human epidermal growth factor receptor 2 therapy but no endocrine therapy. After 61 months of follow-up, no signs of local or distant recurrence were observed.

CONCLUSIONS

Mucoepidermoid carcinoma of the breast is a very rare entity. Despite being most frequently triple negative, the standard evaluation of receptor status is mandatory, as well as strict application of World Health Organization diagnostic criteria for correct patient management.

Breast adenoid cystic carcinoma: An uncommon neoplasm- Case report

INTRODUCTION

Adenoid cystic carcinoma is a neoplasm that is commonly of salivary gland origin. It could infrequently arise from other tissues such as breast in which case it behaves favorably despite belonging to triple-negative breast cancer subgroup.

CASE PRESENTATION

We report a case of a 49-year-old female patient, who presented with right breast pain and upon work-up, was diagnosed with early-stage adenoid cystic carcinoma of the breast. She underwent breast conservation successfully and was advised to get evaluated for adjuvant radiotherapy. The work has been reported in line with the SCARE criteria (Agha et al., 2020).

CLINICAL DISCUSSION

Breast adenoid cystic carcinoma (BACC) is a rare distinct salivary gland-like carcinoma of the breast with similar morphological features to those seen in salivary gland adenoid cystic carcinoma. Surgical resection is the standard mode of treatment in BACC. The role of adjuvant chemotherapy has not proven beneficial in the management of BACC, owing to the similar survival rates seen in patients with and without chemotherapy.

CONCLUSION

Localized breast adenoid cystic carcinoma (BACC) is an indolent disease having optimal response to surgical resection alone and thus can omit adjuvant radiotherapy and chemotherapy when completely excised. Our case is unique as BACC is a rare clinical variant of breast cancer with a very low incidence rate.

Breast lesions with myoepithelial phenotype

Myoepithelial cells (MECs) constitute a continuous layer of cells surrounding the breast glands, localised between the epithelial cells (ECs) and the basal membrane. MECs play important roles in normal mammary gland as they produce basal membrane and stimulate secretion. During neoplastic transformation, MECs act as a barrier preventing stromal invasion. MECs themselves can undergo a great variety of changes, ranging from hyperplastic to metaplastic, to neoplastic, and giving rise to a wide spectrum of morphological pictures sometimes difficult to interpret on routine diagnoses. Several benign and malignant breast tumours can present features of MECs differentiation. As these latter tumours are quite infrequent, the purpose of the present study is to offer a review of the morphological spectrum of MECs lesions, with correlations to prognosis.

Adenoid Cystic Carcinoma of the Breast: Multimodality Imaging Findings and Review of the Literature

RATIONALE AND OBJECTIVES

Adenoid cystic carcinoma (ACC) of the breast is a rare type of breast cancer with favorable prognosis. There is limited data on the radiological findings of this rare tumor in literature. The aim of this study is to determine the most common imaging features and review the literature.

MATERIALS AND METHODS

Pathological databases of seven institutions from 2009 to 2021 were retrospectively reviewed, and patients with a diagnosis of ACC of the breast were determined. Thirteen patients whose imaging studies could be recalled from the picture archiving systems (PACS) were included in the study. Clinical and pathological findings as well as follow-up data were recorded. Radiological findings were analyzed and categorized based on BI-RADS 5th edition.

RESULTS

There were 16 mass lesions in 13 patients (two multifocal cases, one case with recurrence). Mammography demonstrated 14 masses, while ultrasound (US) demonstrated all. MRI was available in only seven cases, with eight masses. The most common findings were round or oval shape on all modalities (78.57%-93.75%). Other frequent findings were parallel orientation (81.25%), isoechoic or hyperechoic echogenicity (62.5%), high T2 signal (87.5%), restricted diffusion (71.43%), and homogeneous enhancement (62.5%). Mammography, US and MRI showed circumscribed margins resembling a benign lesion in 35.71%, 37.5% and 50% of the lesions respectively. Three patients had a cyst-like echogenicty on US. Half of the lesions were avascular on Doppler US (6/12) and half were soft (2/4) on strain elastography. Although there were benign features on all imaging modalities seperately, all lesions could be categorized as BI-RADS 4 or 5 when the findings were combined. However 9/16 masses were BI-RADS 4A, emphasizing the subtlety of the malignant features.

CONCLUSION

ACC of the breast can present with findings resembling a benign lesion on different imaging modalities. Although combination of all imaging findings correctly indicated the suspicious nature of the lesions in all cases, final classification was BI-RADS 4A in most of them. Radiologists should be aware of the more frequent findings of ACC of the breast for early diagnosis. US findings of isoechoic or hyperechoic appearance, and cyst-like echogenicity have not been reported previously in literature.

Prognosis stratification and postoperative radiation therapy utilization in adenoid cystic carcinoma of the breast

PURPOSE

Adenoid cystic carcinoma of the breast (ACCB) is a rare malignancy with a favorable prognosis. Little information exists regarding the impact of postoperative radiation therapy (RT) on survival outcome in patients with ACCB. This study aimed to evaluate the clinical significance of postoperative RT in ACCB.

METHODS

Data of patients with ACCB were extracted from the Surveillance, Epidemiology, and End Results database (2000-2019). Univariate and multivariable Cox regression analyses were performed to identify prognostic factors. In addition, a nomogram model was constructed and internally validated for discrimination and calibration. The value of postoperative RT was respectively accessed in each risk subgroup according to nomogram-deduced individualized score.

RESULTS

A total of 689 eligible patients were included in the analysis. Partial mastectomy was associated with an increased risk of death compared with partial mastectomy plus postoperative RT (P = 0.020), but total mastectomy with or without postoperative RT was comparable (P = 0.624). Then, in-depth analysis was performed for patients receiving breast-conserving therapy (n = 485, the training set vs. the testing set = 340 vs. 145). Age at diagnosis, histological grade, and T stage were identified as prognostic factors for overall survival (OS) (All P < 0.05). A nomogram was constructed to provide predictive accuracy toward individual OS rates of ACCB and to divide patients into different risk subgroups. Notably, compared with non-RT, postoperative RT significantly improved OS in the high-risk subgroup (P = 0.006 for the training set, and P = 0.013 for the overall population) but not in the low-risk subgroup (P = 0.807 for the training set, and P = 0.293 for the overall population), suggesting that these patients may be able to exempt from postoperative RT.

CONCLUSION

A robust and effective nomogram was developed to predict prognosis and assist in treatment decisions in patients with ACCB undergoing partial mastectomy.

Adenoid Cystic Carcinoma of the Breast May Be Exempt from Adjuvant Chemotherapy

Consistent standards regarding whether postoperative adjuvant chemotherapy is required in the treatment of adenoid cystic carcinoma of the breast (ACCB) are currently lacking. Using clinical data from the Surveillance, Epidemiology, and End Results (SEER) database (1988−2015), and the National Cancer Center of China (2004−2020), we retrospectively analyzed patients with ACCB who received radical treatment. A total of 661 patients were eligible. The median age at diagnosis was 61 years; 99.5% of patients were initially diagnosed with stage I and II breast cancer, and 76.7% had triple-negative breast cancer. Only 12.4% of patients received adjuvant chemotherapy. Multivariate analysis showed that patients with lymph node metastasis and non-radiotherapy had worse overall survival (OS) (p < 0.05). Patients with lymph node metastasis, stage IIB and III, histological grade ≥ 2, and non-radiotherapy had worse breast cancer-specific survival (BCSS) (p < 0.05). Adjuvant chemotherapy did not improve the OS or BCSS. Patients treated with adjuvant chemotherapy also had no better survival outcomes after propensity score matching. External data verification confirmed that chemotherapy did not improve disease-free survival or OS. Adjuvant chemotherapy cannot improve the clinical outcomes of ACCB, even in subgroups with a high risk of recurrence and metastasis.

Adenoid Cystic Carcinoma of the Breast in a Male Patient: A Case Report and Literature Review

Adenoid cystic carcinoma (ACC) of the breast (breast ACC) is a rare tumor, especially in men, with only 17 cases reported in the literature. Owing to this rarity, male breast ACC is susceptible to missed or incorrect diagnoses, and data on treatment options and prognosis is also scarce. Herein, we report a case of a male patient with primary breast ACC and performed a detailed clinicopathological analysis of the 17 cases reported in the literature. A 38-year-old Chinese man patient developed right-sided breast nipple retraction in 2013 and presented to our hospital in 2015 with a palpable mass in the right breast for four days. B-scan ultrasound indicated the presence of a solid space-occupying lesion in the right breast. Breast Imaging Reporting and Data System (BI-RADS) classified the lesion as category 4B, and mammography showed a right breast nodule classified as BI-RADS 4C. Modified radical mastectomy for breast cancer was performed on the right breast. Microscopic examination of the excised tissue revealed diffuse tumor invasion of the subcutaneous fibers and adipose tissue, with tumor cells arranged in cribriform, tubular, and microcystic patterns. Immunohistochemical staining indicated that the glandular epithelial cells were positive for CD117, CK7, and Ki67 (approximately 30%) and negative for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2, while the myoepithelial/basal cells were positive for P63, CK5/6 and S-100. Moreover, basement membrane materials were positive for collagen type IV. Molecular pathology analysis by fluorescence in situ hybridization revealed that the tumor was negative for MYB rearrangements. The patient was followed up for 82 months with no tumor recurrence or metastasis. According to the current literature, mastectomies have a better prognosis than lumpectomy. Accurately identifying the diagnosis of male breast ACC and considering the surgery of mastectomy may be the key factors for patients to obtain a good prognosis based on the microscopic characteristics of the tumor.

MYB RNA In Situ Hybridization Is a Useful Diagnostic Tool to Distinguish Breast Adenoid Cystic Carcinoma From Other Triple-negative Breast Carcinomas

Breast adenoid cystic carcinoma (AdCC) has overlapping features with basal-like triple-negative breast carcinoma (TNBC), yet carries a more favorable prognosis, and accurate diagnosis is critical. Like salivary gland AdCC, breast AdCC demonstrates recurrent alterations in the MYB gene. Novel chromogenic RNA in situ hybridization (ISH) for MYB has emerged as sensitive and specific for salivary gland AdCC. Here, we evaluate MYB RNA ISH in invasive ductal carcinomas (IDCs) including basal-like TNBC, and in the histologic mimics ductal carcinoma in situ (DCIS) and collagenous spherulosis. MYB RNA ISH was also performed on previously constructed tissue microarrays containing 78 evaluable IDC, including 30 basal-like TNBC (EGFR+ and/or CK5/6+), 19 luminal A (ER+/HER-2-), 12 HER-2+ (ER-/HER-2+), 11 non-basal-like TNBC, and 6 luminal B (ER+/HER-2+). MYB RNA ISH overexpression was seen in 100% (n=18/18) of primary breast AdCC and 10% (n=8/78) of IDC (P<0.0001). MYB RNA ISH was overexpressed in 37% (n=7/19) of luminal A and 8% (n=1/12) of HER-2+ IDC, and in no cases of TNBC or luminal B IDC. The majority (67%, n=8/12) of DCIS and all (n=7) cases of collagenous spherulosis demonstrated overexpression of MYB RNA. MYB gene rearrangement was detected in 67% (n=4/6) evaluable AdCC. Although MYB RNA ISH overexpression cannot be used to distinguish between cribriform DCIS or collagenous spherulosis and AdCC, MYB RNA ISH is absent in basal-like TNBC and rare in ER+ or HER-2+ IDC. MYB RNA ISH could be a useful, sensitive, and rapid diagnostic adjunct in the workup of a triple-negative carcinoma in the breast.

Distinct clinicopathological and genomic features in solid and basaloid adenoid cystic carcinoma of the breast

Adenoid cystic carcinoma (AdCC) of the breast is a rare indolent carcinoma of salivary gland-type tumors, frequently associated with MYB genetic alteration. Solid and basaloid adenoid cystic carcinoma (SB-AdCC) is considered a sparse variant of AdCC. This study sought to search for clinicopathological and genomic features in SB-AdCC. Registered clinicopathological data on a cohort of 13 AdCC of the breast cases, including six conventional adenoid cystic carcinoma (C-AdCC) cases and seven SB-AdCC cases, were collected. MYB gene rearrangement via fluorescent in situ hybridization was investigated and MYB protein expression was evaluated by immunohistochemistry. Compared with C-AdCC, we found that the distribution of SB-AdCC cases were shifted to older age and were more frequently distant metastasis. Moreover, metastasis cases also showed a high (exceed 30%) Ki-67 index. Both groups showed MYB rearrangements and MYB protein expression, but they were less frequent in SB-AdCC than C-AdCC. To conclude, our results suggest that SB-AdCC is an aggressive variant of mammary AdCC with a higher incidence of distant metastases compared with C-AdCC, though they share common molecular features. A high Ki-67 index may be an adverse prognostic factor for metastasis.

Breast adenoid cystic carcinoma: a report of seven cases and literature review

Background

Primary adenoid cystic carcinoma (ACC) of breast is rarely seen clinically. It is a special subtype of triple-negative breast cancer characterized by low expression of Ki-67, low malignant potential, slow progression and favorable prognosis. To date, treatment for this disease is controversial and no consensus is reached. We analyzed clinical manifestations and pathological characteristics of seven primary breast ACC cases and reported in combination with literature review to promote understanding, diagnosis and treatment of this disease.

Case presentation

We collected seven breast ACC cases pathologically diagnosed and treated in Department of breast surgery of the First Affiliated Hospital of China Medical University from January 2015 to December 2018. We organized and summarized the clinical, imaging, pathological and prognostic information and performed statistical analysis. The median age was 60 years (ranging from 54 to 64 years). Tumors of all patients were detected by immunohistochemistry. Molecular types were mostly triple negative (4/7), and Ki-67 expression was low (5/7). Lymph node metastases were absent in all patients received axillary lymph node surgery. Median follow-up time was 39 months (ranging from 25 to 68 months). There was no occurrence of relapse, distant metastasis or death.

Conclusion

Breast ACC is accompanied with favorable diagnosis, which is different from typical triple-negative breast cancer. Accurate diagnosis of ACC is particularly important.

Primary mucoepidermoid carcinoma of the breast arising in adenomyoepithelioma

Mucoepidermoid carcinoma (MEC) and adenomyoepithelioma (AME) are uncommon neoplasms of the breast that are more commonly noted in the salivary glands. AMEs are benign tumours that are known to undergo malignant transformation. This report describes the first case of a MEC arising in AME in a woman in her 50s.

Special Histologic Type and Rare Breast Tumors - Diagnostic Review and Clinico-Pathological Implications

Breast cancer is the most common malignant tumor in females. While most carcinomas are categorized as invasive carcinoma, no special type (NST), a diverse group of tumors with distinct pathologic and clinical features is also recognized, ranging in incidence from relatively more common to rare. So-called "special histologic type" tumors display more than 90% of a specific, distinctive histologic pattern, while a spectrum of tumors more often encountered in the salivary gland may also arise in the breast. Metaplastic carcinomas can present diagnostic challenges. Some uncommon tumors harbor pathognomonic genetic alterations. This article provides an overview of the key diagnostic points and differential diagnoses for this group of disparate lesions, as well as the salient clinical characteristics of each entity.

Low-risk triple-negative breast cancers: Clinico-pathological and molecular features

Triple-negative breast cancers (TNBC) comprise biologically and clinically heterogeneous diseases characterized by the lack of hormone receptors (HR) and HER2 expression. This subset of tumors accounts for 15-20% of all breast cancers and pursues an ominous clinical course. However, there is a spectrum of low-risk TNBCs with no/minimal metastatic potential, including the salivary gland-type tumors, those with extensive apocrine differentiation and/or high tumor-infiltrating lymphocytes, and small-sized, early-stage (pT1a/bN0M0) TNBCs. De-escalating the treatment in low-risk TNBC, however, is not trivial because of the substantial lack of dedicated randomized clinical trials and cancer registries. The development of new diagnostic and/or prognostic biomarkers based on clinical and molecular aspects of low-risk TNBCs would lead to improved clinical treatment. Here, we sought to provide a portrait of the clinicopathological and molecular features of low-risk TNBC, with a focus on the diagnostic challenges along with the most important biological characteristics underpinning their favorable clinical course.

Adenoid cystic carcinoma of the breast and intraoperative electron radiotherapy: single case report and review of literature

Adenoid cystic carcinoma (ACC) of the breast is a very rare neoplasm. It presents a triple-negative phenotype in most cases, but its prognosis is generally considered to be better than other breast cancers with the same immunohistochemical pattern. Due to its controversial features, no data are available in the literature regarding a consensus approach for ACC treatment, especially for subtypes with worse prognosis like solid basaloid ACC. We present for the first time a rare case of ACC with multifocal presentation treated with breast-conservative surgery and intraoperative electron radiotherapy, thus supporting this treatment of ACC in selected patients like young women affected by the solid basaloid variant who commonly present a worse prognosis. In this case, no local or systemic recurrence was detected after 30 months of follow-up.

Male Adenoid Cystic Carcinoma of the Breast

Adenoid cystic carcinoma (ACC) of the breast, a rare malignancy that makes up less than 0.1% of all breast malignancies, is much rarer in males than in females. Due to the rarity of this disease, an optimal treatment strategy for male breast ACC has not been established, and therapy for male patients is currently based on guidelines for female patients. According to previous reported cases, some authors believe that male breast ACC may have higher invasive potential than female breast ACC and the prognoses in male patients may be worse than those in female patients. Therefore, a more proactive diagnosis and treatment regimen may be required. However, the clinical feature of our case is inconsistent with this view. Herein we report the case of a 24-year-old male without any antecedent medical or family history who presented with a slow-growing lump on his left chest wall for 5 years. The patient initially underwent lumpectomy, and the mass was pathologically diagnosed as breast ACC. Systemic examination was performed, and no evidence of distant metastasis was found. Then, he received modified radical mastectomy and ipsilateral axillary lymph node dissection. The mastectomy pathological examination revealed that no cancerous tissue was detected around the primary tumor bed, and all 22 axillary lymph nodes were negative. The patient did not receive postoperative chemotherapy, radiotherapy or endocrine therapy and remained well after 28 months of follow-up. In this study, we review the literature and summarize the clinical manifestations, imaging and histopathological characteristics, treatments and outcomes of male breast ACC. We share our experience in the hopes that this evidence will aid in the development of better therapeutics.

Triple-Negative Breast Cancer Histological Subtypes with a Favourable Prognosis

Triple-negative breast cancers (TNBC), as a group of tumours, have a worse prognosis than stage-matched non-TNBC and lack the benefits of routinely available targeted therapy. However, TNBC is a heterogeneous group of neoplasms, which includes some special type carcinomas with a relatively indolent course. This review on behalf of the European Working Group for Breast Screening Pathology reviews the literature on the special histological types of BC that are reported to have a triple negative phenotype and indolent behaviour. These include adenoid cystic carcinoma of classical type, low-grade adenosquamous carcinoma, fibromatosis-like metaplastic carcinoma, low-grade mucoepidermoid carcinoma, secretory carcinoma, acinic cell carcinoma, and tall cell carcinoma with reversed polarity. The pathological and known molecular features as well as clinical data including treatment and prognosis of these special TNBC subtypes are summarised and it is concluded that many patients with these rare TNBC pure subtypes are unlikely to benefit from systemic chemotherapy. A consensus statement of the working group relating to the multidisciplinary approach and treatment of these rare tumour types concludes the review.

Adenoid cystic carcinoma and basaloid carcinoma of the breast: A clinicopathological study

Adenoid cystic carcinoma of the breast (ACCB) is a rare triple negative tumor (TNT) with an excellent prognosis in most cases. Three different histologic types are recognized: classic ACCB, solid basaloid ACCB (SB-ACCB), and ACCB with high-grade transformation. A majority of these tumors show characteristic molecular and immunohistochemical (IHC) features, with fusion of MYB and NFIB genes and overexpression of MYB, respectively. Basaloid carcinomas of the breast (BCB) are infrequently described. They resemble SB-ACCB and TNT of no special type (TNT-NST). We have studied the clinicopathological features of 17 ACCB and 9 BCB, investigating the expression of MYB by IHC and the rearrangements of MYB by fluorescence in situ hybridization (FISH). MYB was expressed by IHC in 15 ACCB and in 3 BCB. MYB FISH detected rearrangements in 11 ACCB and in 2 BCB. After a mean follow-up of 90 months, with a range of 12-204 months, 2 patients with ACCB with high-grade transformation and 1 patient with BCB developed metastases and died of disease. In summary, most ACCB have a good prognosis, but tumors with adverse histopathological features may metastasize. BCB may overlap with ACCB and TNT-NST, and their prognosis should be further studied.

Treatment of adenoid cystic carcinoma of the breast: Is postoperative radiation getting its due credit?

Introduction

The role of postoperative radiation (PR) in treating mammary ACC is poorly defined. This study evaluated the impact of PR on survival outcomes for mammary ACC and the extent of utilization.

Methods

Patients who underwent surgery for mammary ACC from 2005 to 2015 in SEER database were analyzed. KM analyses of OS and DSS were done for PR versus no PR. Cox hazard regression models were used to determine predictors of OS and DSS.

Results

Of the 488 patients, 244 underwent PR. The PR group was younger, but other variables were similar between the 2 groups. OS was better for PR (p = 0.029). 10-year DSS was better for PR group by an absolute value of 6 % but did not reach statistical significance (p = 0.537). Age, radiation, nodal metastasis, and grade III/IV were independent predictors of OS while grade III/IV and AJCC stage III/IV independently predicted DSS.

Conclusion

PR improves OS for mammary ACC, but this study did not show increased utilization. Radiation should be considered after surgery for mammary ACC, particularly for patients with independent predictors of OS.

•

The role of postoperative radiation (PR) in the management of mammary adenoid cystic carcinoma (ACC) is still poorly defined.

•

Postoperative radiation improves OS for mammary ACC.

•

Despite previous studies demonstrating benefits of PR, this study did not show increased use of the treatment modality.

•

PR should be considered for mammary ACC, particularly for patients with negative independent predictors of OS.

Adenoid Cystic Carcinoma of the Breast

BACKGROUND

Contrast-enhanced spectral mammogram (CESM) is a modern technique providing additional information to detect or diagnose breast cancers.

INTRODUCTION

We present a rare ACC of the breast on CESM.

METHODS

A 49-year-old woman with surgicopathological proved ACC was reported with tumor features on CESM, sonography and contrast-enhanced magnetic resonance imaging (CE-MRI).

RESULTS

Sonography revealed a 1.4 cm × 1.2 cm × 1 cm circumscribe round mass in the upper outer quadrant of the left breast that was diagnosed with fibroadenoma. The mammogram did not show any discernible mass, however, the recombined subtracted images displayed a circumscribe mass with thin rim enhancement and enhanced internal patches that were resembling CE-MRI. Finally, the mass was proved to ACC.

CONCLUSION

CESM facilitates the detection of isodense cancer and provides the enhanced features for differential diagnosis. Resembling CE-MRI, CESM displayed rim enhancement and internal enhanced patches as diagnostic clues for this case of ACC.

Management of Adenoid Cystic Carcinoma of the Breast: A Single-Institution Study

Objective

The purpose of our study was to analyze the clinicopathologic features and surgical and oncological outcomes of adenoid cystic carcinoma (ACC) of the breast and to provide the basis for a clinical therapeutic schedule.

Methods

A total of 14 patients with primary breast adenoid cystic carcinoma treated at Cancer Hospital of the Chinese Academy of Medical Sciences from January 2000 to December 2017 were included. Data on clinical presentation, treatment strategy, and outcome, as well as the pathological features of ACC, were reviewed and analyzed.

Results

Fourteen patients were diagnosed with ACC of the breast, out of 23205 total patients treated for breast cancer (0.06%). All but three patients were postmenopausal, with a median age at diagnosis of 60.5 years (range, 39–73 years). The most common clinical presentation was a palpable mass (85.7%), and the imaging characteristics of all patients on color Doppler ultrasound and mammography were nonspecific. Six patients (42.9%) were suspected of having ACC by fine-needle aspiration cytology (FNAC) and were confirmed by postoperative histology and immunohistochemistry. All 14 patients underwent surgery, and no patient had a positive lymph node status. Median tumor size was 1.75 cm (range, 1–3 cm). Eight/14 (57.1%) patients were hormone receptor negative (HR−) and HER-2/neu (−) (HER2−). The remaining patients were hormone receptor positive (HR+). There was no significant difference in clinicopathological characteristics between the HR+ group and the HR- group (P>0.05). The mean follow-up period was 57 months. Local recurrence occurred in 14.3% of patients, 1.7% of patients had distant metastasis, all patients with local recurrence or distant metastasis were in the HR (-) group, and all patients were alive at the last follow-up.

Conclusion

ACC of the breast cannot be simply summarized as triple-negative breast cancer because it also includes a small number of hormone receptor-positive breast cancers. Establishing a preoperative diagnosis is difficult on the basis of clinical imaging examination, FNAC may be useful tool in the diagnosis. the final diagnosis can only be assessed based on the results of the histopathological and immunohistochemical examination. Breast-conserving surgery may be an alternative treatment strategy, and axillary lymph node dissection or sentinel node biopsy may not be necessary in some cases.

Adenoid cystic carcinoma of the breast - an uncommon malignancy with unpredictable clinical behaviour. A case series of three patients

Adenoid cystic carcinoma (AdCC) is a common tumour of the minor salivary gland, rarely seen in other anatomical locations. In particular, AdCC of the breast accounts for < 0.1% of patients diagnosed with breast cancer. Here we report our institutional experience with three cases of breast AdCC diagnosed between 2009 and 2017. Mean age of women included in the report was 53 (range from 41 to 62). One case was of no special subtype, two were solid variants and one presented with a component of invasive ductal carcinoma. At diagnosis in all cases neither lymph node involvement nor distal metastases were detected. All patients underwent surgical resection of the tumour - mastectomy or lumpectomy, followed by either adjuvant radiotherapy and chemotherapy (one case), chemotherapy without radiotherapy (one case) or no treatment (one case). Two patients were reported to develop metastatic disease. No deaths were recorded. In contrast to other anatomical locations AdCC of the breast is regarded as a rare tumour with low malignant potential. However, as shown in our case series, it can present as an aggressive disease with distal metastases, which calls for deep awareness among both pathologists and clinicians involved in the process of diagnosis and therapy.

Prognostic and predictive parameters in breast pathology: a pathologist's primer

The pathologist's role in the breast cancer treatment team has evolved from rendering a diagnosis of breast cancer, to providing a growing list of prognostic and predictive parameters such that individualized treatment decisions can be made based on likelihood of benefit from additional treatments and potential benefit from specific therapies. In all stages, ER and HER2 status help segregate breast cancers into treatment groups with similar outcomes and treatment response rates, however, traditional pathologic parameters such as favorable histologic subtype, size, lymph node status, and Nottingham grade also have remained clinically relevant in early stage disease decision-making. This is especially true for the most common subtype of breast cancer; ER positive, HER2 negative disease. For this same group of breast cancers, an ever-expanding list of gene-expression panels also can provide prediction and prognostication about potential chemotherapy benefit beyond standard endocrine therapies, with the 21-gene Recurrence Score, currently the only prospectively validated predictive test for this purpose. In the more aggressive ER-negative cancer subtypes, response to neoadjuvant therapy and` the extent of tumor infiltrating lymphocytes (TILs) are more recently recognized powerful prognostic parameters, and clinical guidelines now offer additional treatment options for those high-risk patients with residual cancer after standard neoadjuvant therapy. In stage four disease, predictive tests like germline BRCA status, tumor PIK3CA mutation status (in ER+ metastatic disease) and PDL-1 status (in triple negative metastatic disease) are now used to determine additional new treatment options. The objective of this review is to describe the latest in prognostic and predictive parameters in breast cancer as they are relevant to standard pathology reporting and how they are used in breast cancer clinical treatment decisions.

Adenoid cystic carcinoma of the breast: a study of five cases

Adenoid cystic carcinoma of the breast is a rare type of breast cancer. Most patients present with a bilateral palpable mass. Ultrasound and mammography are non-specific and can sometimes lead to misdiagnosis because of their variable imaging features. Pathological examination is the standard reference. Surgery is the mainstay of treatment for patients. Although adenoid cystic carcinoma has an excellent prognosis, metastatic cases have been reported. This report aims to discuss the clinical and imaging features of one case of adenoid cystic carcinoma with a poor prognosis and four cases with a good prognosis at our center.

Diagnosis of metastatic adenoid cystic carcinoma of the breast on pleural fluid cytology in a 60-year-old male

Adenoid cystic carcinoma (AdCC) is a rare triple-negative breast cancer with a favorable prognosis, although cases of distant metastases have been reported. Less than 10 cases of AdCC of the breast in males have been reported. We report a unique presentation of pleural fluid metastasis diagnosed by cytologic evaluation of pleural fluid in a 60-year-old male patient with AdCC of the breast. Careful surveillance and cytologic evaluation of effusion specimens can detect metastases with the aid of cellblock preparations and immunohistochemical stains.

[Adenoid cystic carcinoma of the breast, 22 years of experience]

INTRODUCTION

Adenoid cystic carcinoma (ACC) is an uncommon neoplasm in the breast (less than 0.1%). ACC is typically triple negative with a favourable prognosis. Its low frequency and indolent course cause difficulties in the agreement of the evaluation and therapeutic consensus, as well as the use of the sentinel node excision in these carcinomas.

OBJECTIVE

Our goal is to provide a new series of cases from the Complejo Hospitalario de Navarra, through retrospective review over a period of 22 years.

MATERIAL AND METHODS

Every case of breast ACC diagnosed between 1998-2020 is reviewed. We analyze the clinical and pathological characteristics, and compare them with the literature.

RESULTS

We identified twelve cases of ACC, from a total of 18,241 patients diagnosed with breast carcinoma, with an average tumor size of 23.8mm and mean of 63.5 years. All of them were in a stage I-II at diagnosis. One case presented a lymph node micrometastases. One of them presented local recurrences and one case presented metastases 5 months after diagnosis (93.5 months of mean follow-up). According to Nottingham Histological Score, eight cases had a grade 1, two grade 2 and two grade 3. According to the classification of Ro et al., three were grade 1, four grade 2 and five grade 3. One case was ER positive (10%). No case presents positivity for BRAF-V600E in immunohistochemistry.

CONCLUSION

The management and prognosis ACC of breast, within benignity, remains uncertain, with more studies being needed to understand the clinical evolution and perform adequate therapeutic management.

Concurrent breast adenoid cystic carcinoma and primary squamous cell carcinoma: report of a rare case with single institutional case reviews

Background

Adenoid cystic carcinoma and primary squamous cell carcinoma are both rare breast neoplasms, which possess drastically different morphological and molecular features as well as distinguishing clinical behaviors and prognosis.

Case presentation

In this report, we described a rare case in which concurrent adenoid cystic carcinoma and keratinizing squamous cell carcinoma were diagnosed in contralateral breasts in an 85 year-old female patient. The patient had a history of adenoid cystic carcinoma diagnosed 11 years ago, which was treated by partial mastectomy followed by whole breast radiation. The recurrent carcinoma on the same side of the breast was small in size but appeared to involve an intraductal papilloma. Also, a newly occurred large cystic mass was identified on the contralateral breast, which histologically presented as a keratinizing squamous cell carcinoma with no glandular differentiation. No in situ or invasive carcinoma was identified in the overlying skin of the lesion, and no malignancy in a second site was found by PET-CT. Therefore, this lesion was mostly likely a primary squamous cell carcinoma of the breast.

Conclusion

The concurrence of two such rare neoplasms was likely an incidental finding or was therapy-related. However, more mechanistic studies are needed in order to understand whether predisposing genetic alterations exist in this rare case. Besides, cases of both breast adenoid cystic carcinoma and carcinoma with predominant squamous differentiation diagnosed in our institution were reviewed, which help to better characterize their clinicopathological features.

A review of mucinous lesions of the breast

Mucinous lesions of the breast include a variety of benign and malignant epithelial processes that display intracytoplasmic or extracellular mucin, including mucocele-like lesions, mucinous carcinoma, solid papillary carcinoma, and other rare subtypes of mucin-producing carcinoma. The finding of free-floating or stromal mucin accumulations is a diagnostic challenge of which the significance depends on the clinical, radiologic, and pathologic context. This article emphasizes the differential diagnosis between benign and malignant mucin-producing lesions, with a brief consideration of potential mimics, such as biphasic and mesenchymal lesions with associated with mucinous, myxoid, or matrix material.

Liver metastasis from adenoid cystic carcinoma of the submandibular gland: a case report

BACKGROUND

Adenoid cystic carcinoma (ACC) is a rare malignancy of epithelial origin. It involves a variety of histologic types and often has distant metastasis. ACC metastasis to the liver is rare and usually involves spread to other organs.

CASE PRESENTATION

We report a case of liver metastasis from a submandibular gland adenoid cystic carcinoma 11 years after resection of tumor. The patient was admitted to our hospital due to a liver-occupying lesion found by abdominal B-ultrasound, CT and MRI. A metastasis was found only in the liver, and after discussion the patient was treated with surgery. This tumor was histologically consistent with the diagnostic criteria of ACC. The patient was followed up 24 months after surgery, and showed no recurrence in the liver parenchyma at the site of operation or other organs.

CONCLUSIONS

ACC is a very rare tumor and its pathogenesis is not completely clear. There are few articles about the imaging findings of ACC in the liver, and so it was difficult for us to make a correct diagnosis in clinical practice. The diagnosis of ACC mainly relies on pathologic examination, so we summarize the correlation between imaging and pathology.

Androgen Receptor Expression in Adenoid Cystic Carcinoma of Breast: A Subset of Seven Cases

Objective

Adenoid cystic carcinoma (ACC) of the breast is an uncommon salivary type of breast carcinoma. It is a triple negative breast carcinoma with a basal-like phenotype that behaves in an indolent manner. Herein, we aimed to document clinicopathologic findings and hormone receptor status of ACC in the breast diagnosed in our institution during an eleven-year period.

Materials and Methods

Medical data of cases diagnosed as adenoid cystic carcinoma in the breast between January 2006 and December 2016 were retrospectively reviewed from hospital data base. Paraffin blocks of seven cases were retrieved from the archive of Pathology Department and androgen receptor (AR) immunohistochemistry was applied to each case.

Results

All of the cases diagnosed as ACC were females with a mean age 56.2. Solid growth pattern was present in two cases. P63 was constantly expressed in the whole group, and at least one additional myoepithelial marker (calponin, caldesmon, etc.) was co-expressed in tumors. While weak estrogen receptor expression was detected only in one patient, AR was strikingly expressed in majority (%85.7) of the tumors.

Conclusion

To our knowledge, our series is the first to report such high levels of AR expression. This new finding, in turn, suggests considering hormonal therapy as an option in the management of ACC of the breast.

Adenoid Cystic Carcinoma of the Breast: A Case Report

Adenoid cystic carcinomas (ACCs) are malignant tumors that most often occur in the salivary glands and bronchi, with occurrence in the breast being rare. ACCs of the breast reportedly give rise to few lymph node metastases or distant metastases and have a favorable prognosis. A 56-year-old woman with a left breast mass identified by mammographic screening was examined at our institute. Breast ultrasound revealed a sharply marginated, hypoechoic mass 12.7 × 9.4 × 8.7 mm in size in the upper outer quadrant of the left breast, and a vacuum-assisted biopsy (VAB) was performed at the mass site. Pathological examination of the VAB specimen revealed atypical cells with a cribriform growth pattern, and mucosal fluid surrounding tumor nests and within tumor ducts. The area around the tumor nests and inside of tumor ducts were also positively stained with alcian blue. These findings, we reached a pathological diagnosis of ACC. The preoperative diagnosis was stage I (cT1N0M0) triple-negative left breast cancer. Surgery consisted of breast-conserving surgery and sentinel node biopsy. The excised specimen was a 15.0 × 12.1 × 9.7 mm mass with a greyish white cut surface. Pathological examination of the excised specimen revealed a so-called adenoid cystic pattern. Results from immunohistochemical staining were identical to those from a VAB specimen, as they were estrogen receptor-negative, progesterone receptors-negative, and human epidermal growth factor receptor 2-negative, with low Ki67 expression. The final diagnosis, given the above findings, was left breast cancer (ACC) pT1N0M0 stage I triple-negative subtype.

Adenoid cystic carcinoma of the breast in a male: A case report

RATIONALE

Adenoid cystic carcinoma (ACC) of the breast is an infrequent neoplasm, and the occurrence in males is rare. Therefore, diagnostic and therapeutic challenges are inevitable.

PATIENT CONCERNS

Herein, we present a case of a 44-year-old man with a tumor on his right breast that he had known about for 6 years.

DIAGNOSES

The patient underwent a lumpectomy, and the histological examination confirmed a diagnosis of ACC.

INTERVENTIONS

Modified radical mastectomy was subsequently conducted in the patient. No positive lymph nodes were observed in the postoperative pathological examination. Following the surgery, the patient received adjuvant chemotherapy.

OUTCOMES

The patient remained recurrence-free at 26 months.

LESSONS

Compared to female breast ACC, male breast ACC may behave differently biologically and have a different prognosis. Our case will provide more diagnostic and treatment experience to deal with this disease.

SOX10 Is a Sensitive Marker for Breast and Salivary Gland Adenoid Cystic Carcinoma: Immunohistochemical Characterization of Adenoid Cystic Carcinomas

Breast adenoid cystic carcinomas (AdCCs) can pose diagnostic difficulty due to their rarity, particularly on limited biopsy material. Given that these tumors are triple-negative breast cancers with favorable prognosis, accurate diagnosis is critical for clinical management. A total of 12 cases of breast AdCCs were studied; 17 age-matched salivary gland AdCCs and 5 metastatic AdCCs (1 breast and 4 salivary gland primaries) were also examined. Immunohistochemical stains for SOX10, Ki-67, c-KIT, β-catenin, epithelial membrane antigen (EMA), p63, cytokeratin 7 (CK7), cytokeratin 5/6 (CK5/6), and androgen receptor (AR) were performed. All breast (100%) and metastatic (100%) AdCCs and all but 2 salivary gland AdCCs showed diffuse nuclear staining (>50% of cells) for SOX10. Epithelial membrane antigen showed lowest expression in breast AdCCs and the highest expression in metastatic AdCCs (P < .01). Except one case of salivary gland AdCC that showed loss of β-catenin expression and developed subsequent metastasis, all AdCCs showed strong and diffuse membranous β-catenin expression. There were no significant differences in expression of CK7, p63, CK5/6, AR, Ki-67, and c-KIT (P > .05) among breast, salivary gland, and metastatic AdCCs. We investigated the immunophenotypic features of breast AdCCs in comparison with salivary gland and metastatic AdCCs. Despite the contrast in prognosis, these tumors are immunophenotypically similar. SOX10 is a sensitive diagnostic marker in all AdCCs, which could potentially aid in diagnosis of these tumors on limited material.

Adenoid cystic carcinoma of the breast

Adenoid cystic carcinoma of the breast (ACC) is a rare tumor, comprising <0.1% of all breast cancers. It has a unique dual-cell pattern and is indistinguishable from ACC arising from salivary tissue. It is a low-grade tumor with favorable prognosis, and rare metastasis, with unique features. It is more commonly seen in older women with a mean age at diagnosis of 63, with Caucasian women being at greatest risk. Most cases present as a painful, palpable mass in the outer quadrants of the breast, and must be diagnosed via core needle biopsy or surgical excisional biopsy. Although few other cancers resemble ACC it is commonly misdiagnosed. Given the rarity of this cancer, treatment guidelines have yet to be well established. Current treatment is focused around surgical resection, however, there are not specific recommendations for the extent of resection due to the lack of cases to draw from.

Adenoid cystic carcinoma of the vagina: A case report

RATIONALE

Squamous carcinoma is the most common malignancy of vagina. Adenoid cystic carcinoma (ACC) in the vagina is very rare.

PATIENT CONCERNS

In the present study, we present a 45-year-old woman with a palpable swelling in the vagina. The patient reported body paresthesia, chest congestion, expiratory dyspnea, and itching in the thigh root.

DIAGNOSIS

The ultrasound results revealed inhomogeneous echoes of the muscular layer in the middle and distal of the vagina, and probed a slightly richer blood flow signal. Then biopsy was performed. On microscopic examination, it was observed that tumor cells were arranged in a tubular or cribriform pattern, and exhibited a consistent size, small nuclei, and nuclear fission. The myoepithelium was lined around the glandular cavity, but the myoepithelium was tumorous. Immunohistochemistry was performed for further verification. Vimentin was positive in mesenchyme and CK-P was positive in epithelial cells. P63 and calponin were spotted, which were focal positive around the glandular cavity. Finally, the patient was diagnosed as ACC.

INTERVENTIONS

At last, the patient chose chemoradiotherapy, not surgical excision.

OUTCOMES

The patient is alive and well 13 months after the initial diagnosis.

LESSONS

ACC in the vagina is extremely rare. To our knowledge, this report is the first case of ACC arising from the vagina in English-language literature. Extensive surgical section of the tumour and chemoradiotherapy are recommended for therapy. Because of rarity, the prognosis of ACC in vagina is not known.

NFIB promotes cell survival by directly suppressing p21 transcription in TP53-mutated triple-negative breast cancer

Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype with limited treatment options and poor prognosis. There is an urgent need to identify and understand the key factors and signalling pathways driving TNBC tumour progression, relapse, and treatment resistance. In this study, we report that gene copy numbers and expression levels of nuclear factor IB (NFIB), a recently identified oncogene in small cell lung cancer, are preferentially increased in TNBC compared to other breast cancer subtypes. Furthermore, increased levels of NFIB are significantly associated with high tumour grade, poor prognosis, and reduced chemotherapy response. Concurrent TP53 mutations and NFIB overexpression (z-scores > 0) were observed in 77.9% of TNBCs, in contrast to 28.5% in non-TNBCs. Depletion of NFIB in TP53-mutated TNBC cell lines promotes cell death, cell cycle arrest, and enhances sensitivity to docetaxel, a first-line chemotherapeutic drug in breast cancer treatment. Importantly, these alterations in growth properties were accompanied by induction of CDKN1A, the gene encoding p21, a downstream effector of p53. We show that NFIB directly interacts with the CDKN1A promoter in TNBC cells. Furthermore, knockdown of combined p21 and NFIB reverses the docetaxel-induced cell growth inhibition observed upon NFIB knockdown, indicating that NFIB's effect on chemotherapeutic drug response is mediated through p21. Our results indicate that NFIB is an important TNBC factor that drives tumour cell growth and drug resistance, leading to poor clinical outcomes. Thus, targeting NFIB in TP53-mutated TNBC may reverse oncogenic properties associated with mutant p53 by restoring p21 activity. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Adenoid cystic carcinoma of the breast: Experience at a tertiary care centre of Northern India

INTRODUCTION

Adenoid cystic carcinoma of the breast (breast-ACC) is a rare tumor with a favorable prognosis, despite its triple-negative status and special type of basal-like tumor for which scant population-based descriptive data exist. We sought to provide new population-based information on breast-ACC in India. Due to the paucity of the number of cases, the natural history of the disease is not fully understood. This study was undertaken to examine the clinico-pathological characteristics of the disease and to evaluate the outcome of surgical intervention in a tertiary referral care centre.

MATERIALS AND METHODS

A retrospective analysis of all patients diagnosed and treated for ACC Breast in our hospital over the past 10 years was carried out (2005-2015). A database of the characteristics of these patients was developed. In all, 14 patients were identified. The investigations performed included routine blood investigations, chest X-ray, bone scan and either an ultrasound or a CT scan.

RESULTS

During the time period of 10 years, of 2347 with breast malignancy admitted to our department, only 14 were diagnosed as having ACC (3.15%). All patients were women (100%). The patients had a median age of 60.7 years (range 37-81). The most common symptom was lump in the breast. Two patients (14.2%) presented with nipple and skin retraction and two patients (14.2%) were asymptomatic with the diagnosis made by an incidental finding on routine examination. The CT and/or magnetic resonance imaging (MRI) showed the typical features of carcinoma breast. All the 14 patients were taken up for surgery. Nine patients underwent Modified radical mastectomy and five patients underwent Breast conservation surgery. Axillary lymph node dissection was carried out in seven patients and sentinel lymph node biopsy in the remaining. Tumor cells had a characteristic histologic pattern of ACC of the breast. Perineural invasion was present in six cases.

DISCUSSION

ACC of the breast is a very rare malignancy, accounting for less than 0.1% of all breast neoplasms. It affects the left and right breasts equally and tumors arise irrespective of the breast quadrants. However, in about 50 percent of patients, lesions are found in subareolar region. Pain or tenderness described in the minority of cases has not been correlated with histologically-confirmed perineural invasion. ACC is categorized as a basal-like subtype of breast carcinoma. Most cases are macroscopically well-circumscribed. Occasionally, pink, tan, or gray microcysts are evident. A tumor typically consists of a dual-cell population of luminal and myoepithelial-basal cells which may be arranged in one or more of three architectural patterns: tubular-trabecular, cribriform, and solid-basaloid. There is no consensus on the optimal management for patients with ACC of the breast. Based on its indolent clinical course and favorable outcome, ACC of the breast is generally cured by breast-conserving surgery, such as wide excision or quadrantectomy with or without radiotherapy.

CONCLUSION

Breast-ACC among women is characterized by ER-negative/PR-negative expression, rare regional lymph node involvement, a favorable prognosis with excellent survival, and absence of associated cancers. These findings reinforce the importance of tailored treatments for breast-ACC and the apparent heterogeneity of basal-like breast cancers.

Similar outcomes between adenoid cystic carcinoma of the breast and invasive ductal carcinoma: a population-based study from the SEER 18 database

Adenoid cystic carcinoma of the breast (breast-ACC) is a rare and indolent tumor with a good prognosis despite its triple-negative status. However, we observed different outcomes in the present study. Utilizing the Surveillance, Epidemiology, and End Results (SEER) database, we enrolled a total of 89,937 eligible patients with an estimated 86 breast-ACC cases and 89,851 invasive ductal carcinoma (IDC) patients. In our study, breast-ACC among women presented with a higher proportion of triple-negative breast cancer (TNBC), which was more likely to feature well-differentiated tumors, rare regional lymph node involvement and greater application of breast-conserving surgery (BCS). Kaplan-Meier analysis revealed that patients with breast-ACC and breast-IDC patients had similar breast cancer-specific survival (BCSS) and overall survival (OS). Moreover, using the propensity score matching method, no significant difference in survival was observed in matched pairs of breast-ACC and breast-IDC patients. Additionally, BCSS and OS did not differ significantly between TNBC-ACC and TNBC-IDC after matching patients for age, tumor size, and nodal status. Further subgroup analysis of molecular subtype indicated improved survival in breast-ACC patients with hormone receptor-positive and human epidermal growth factor receptor 2-negative (HR+/Her2-) tumors compared to IDC patients with HR+/Her2- tumors. However, the survival of ACC-TNBC and IDC-TNBC patients was similar. In conclusion, ACCs have an indolent clinical course and result in similar outcomes compared to IDC. Understanding these clinical characteristics and outcomes will endow doctors with evidence to provide the same intensive treatment for ACC-TNBC as for IDC-TNBC and lead to more individualized and tailored therapies for breast-ACC patients.