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

Imaging Features and World Health Organization Classification of Rare Breast Tumors

Breast radiologists encounter unusual lesions, which may not be well described in the literature. Previously based on histologic and molecular classifications, the World Health Organization (WHO) classification of tumors has become increasingly multidisciplinary. Familiarity with imaging features and basic pathology of infrequent breast lesions, as well as their current classification according to the WHO, may help the radiologist evaluate biopsy results for concordance and help direct the management of uncommon breast lesions. This review article provides a case-based review of imaging features and WHO histologic classification of rare breast tumors.

Tremendous and infrequently adenoid cystic carcinoma of the breast without any metastasis for more than 20 years: A case report

RATIONALE

Breast adenoid cystic carcinoma is an extremely rare tumor that is incompletely understood, accounting for less than <0.1% of all breast cancers, with an average diameter of 3 cm, and it is extremely rare to see a large, non-metastatic breast adenoid cystic carcinoma with a diameter of about 30 cm. Since this disease is extremely rare, there are few reports in the literature and limited data on clinical diagnosis and treatment. We present a case of a 71-year-old woman with a large, non-metastatic adenoid cystic carcinoma of the left breast and share our opinion on the diagnosis and treatment of this case.

PATIENT CONCERNS

A 71-year-old woman with a 20-year-old left breast mass with local bleeding and rupture for 1 hour presented to our hospital for further diagnosis and treatment. A computed tomography scan showed a large soft tissue mass shadow in the left breast and malignancy was considered. Subsequently, tissue aspiration pathology was performed and the results confirmed adenoid cystic carcinoma of the breast.

DIAGNOSIS

Intraoperative pathology results of radical mastectomy for left breast cancer diagnosed adenoid cystic carcinoma of the breast and immunohistochemistry results of triple-negative breast cancer.

INTERVENTIONS AND OUTCOMES

Treatment of adenoid cystic carcinoma of the breast included neoadjuvant chemotherapy for breast cancer, radical mastectomy of the left breast, and postoperative chemotherapy. Initially, neoadjuvant chemotherapy for breast cancer was performed, and the TAC regimen was used to successfully reduce the size of the tumor and gain access to surgical treatment for breast cancer. The patient has recovered well after the surgery, with no wound infection or ulceration, and is now waiting for the patient's physical function to recover for postoperative chemotherapy, with no obvious discomfort.

LESSONS

Adenoid cystic carcinoma tumors are usually around 3 cm; such a huge 30 cm adenoid cystic carcinoma of the breast is extremely rare, and it is extremely rare to find a breast malignancy that has not developed regional lymph node and distant metastases for more than 20 years. Clinicians must remain vigilant for early breast malignancies at a high age of incidence and conduct further research for diagnosis to avoid delays.

Adenoid Cystic Carcinoma of the Breast: Two Case Reports

In this series of case reports, we present two women diagnosed with rare cancer, adenoid cystic carcinoma (ACC) of the breast. Though this neoplasm has a relatively favorable prognosis, more information regarding its pathophysiology, response to variable treatments, and long-term prognosis is needed. The objective of our case series is to present the medical decisions and clinical courses of a 50-year-old female and a 79-year-old female with ACC of the breast. Through ongoing shared knowledge from cases like ours and further experimental research, a more reliable diagnostic and treatment algorithm can be substantiated.

Adenoid cystic carcinoma of the breast with late recurrence and high-grade transformation

Breast cancers have broad histological subtypes with varied molecular expression, which determines the management. Although ductal and lobular breast carcinomas constitute the significant 90% of these tumours, other subtypes constitute about 10% of breast cancers. Adenoid cystic carcinoma (AdCC) is a salivary gland-type tumour described in breast, constituting less than 1% of all breast carcinomas. These tumours have a favourable prognosis and are surgically managed by either lumpectomy or mastectomy. Solid-basaloid and AdCC with high-grade transformation are the sporadic subtypes of AdCC, in addition to the classic type. We report a case of recurrent AdCC which was surgically managed by modified radical mastectomy initially and presented with recurrence and high-grade transformation 11 years later.

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 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.

Treatment response to eribulin and anlotinib in lung metastases from rare perianal adenoid cystic carcinoma: a case report

Adenoid cystic carcinoma (ACC) is a rare salivary glands tumor and often displays aggressive behavior with frequent relapse and metastasis. The terminal ACC lacks standard treatment guidelines and is always accompanied by poor prognosis. Here, we report a case of rare perianal ACC who received resection and palliative adjuvant radiation. Five years later, PET-computed tomography (CT) showed perianal recurrence and multiple pulmonary metastases. Combined chemotherapy with doxorubicin, carboplatin and cyclophosphamide was applied for two cycles but ineffective. Further next-generation sequencing analysis of perianal tissue demonstrated the v-myb avian myelobastosis viral oncogene homolog and nuclear factor I/B fusion gene and two novel BCL-6 corepressor (BCOR) mutations (p.F1106Tfs*5 and p.L1524Hfs*8). The therapy was switched to eribulin and anlotinib and has been performed for eight cycles. At recent follow-ups, MRI and CT examinations revealed the diminishing perianal and pulmonary lesions. This study presented the first case of perianal ACC with multiple pulmonary metastases and particular BCOR mutations, who presented a durable response to eribulin and anlotinib, providing a potential therapeutic option for advanced refractory ACC.

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.

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.