Expression of hormone receptors in low-grade adenosquamous carcinoma of the breast: A case report

Low-Grade Adenosquamous Carcinoma of the Breast: A Single-Center Retrospective Study and a Systematic Literature Review

(1) Low-grade adenosquamous carcinoma (LGASC) is a rare subtype of metaplastic breast carcinoma (MpBC), accounting for fewer than 0.05% of breast cancer cases. Unlike the typically aggressive nature of MpBCs, LGASC is an indolent tumor with an excellent prognosis. Due to its rarity, LGASC is frequently misdiagnosed, particularly in core needle biopsies. Currently, there are no clear treatment guidelines for LGASC. (2) Methods: This study presents a single-center retrospective analysis and a systematic literature review of LGASC. (3) Results: Three LGASC cases were diagnosed among 6462 breast cancer patients in our center, demonstrating its rarity. LGASC has overlapping features with benign sclerosing lesions and is often initially misdiagnosed. LGASC is often overtreated, as its indolent nature is not recognized. It very rarely presents axillary or distant metastases, and in contemporary data, local recurrences are rare, questioning the need for adjuvant therapy. (4) Conclusions: LGASC is a very rare form of breast cancer with an excellent prognosis despite being MpBC and usually a triple-negative breast cancer. It is often overtreated as its unique nature is not recognized.

Hormone receptor expression in low-grade adenosquamous carcinoma of the breast progressing to high-grade metaplastic carcinoma: A case report

RATIONALE

Breast low-grade adenosquamous carcinoma is an uncommon cancer that has been neglected in genetic and pathophysiological research. Consequently, medical practitioners face challenges in the effective diagnosis and treatment of this condition.

PATIENT CONCERNS

We present the case of a 57-year-old Asian female patient who presented with bilateral breast masses on physical examination. Ultrasound and an MRI revealed a highly suspicious malignant mass in her right breast that was completely removed surgically.

DIAGNOSES

After pathological analysis, the diagnosis was low-grade adenosquamous carcinoma with local high-grade transformation, and some of the tumor components were estrogen receptor positive.

INTERVENTIONS

The patient underwent appropriate postoperative chemotherapy and achieved a favorable outcome.

OUTCOMES

During the follow-up period after surgical resection, the patient did not experience any local recurrence or distant metastasis.

LESSONS

Owing to the rare combination of estrogen receptor positivity and high-grade progression, this patient also required adjuvant chemotherapy. This enhances the essential foundation for diagnosing and treating this rare disease, and facilitates the implementation of treatment plans.

Low-Grade Adenosquamous Carcinoma of the Breast Masquerading as a Fibroepithelial Lesion on Core Biopsy: A Challenging Case

INTRODUCTION

Diagnosing low-grade adenosquamous carcinoma (LGASC) presents significant challenges due to its subtle morphology, variable immunohistochemical expression, and resemblance to benign lesions like radial scar and complex sclerosing lesions.

CASE PRESENTATION

We present a case of a 53-year-old woman with a subareolar mass initially thought to be a fibroepithelial neoplasm on core biopsy. Subsequent wide excision revealed LGASC with oestrogen receptor expression (weak to moderate intensity, 40% of tumour cells).

CONCLUSION

These findings, rarely reported, highlight the difficulty of diagnosing LGASC on small tissue samples.

Metaplastic Carcinoma of the Breast: Case Series of a Single Institute and Review of the Literature

Metaplastic carcinoma of the breast (MpBC) is a very rare and aggressive type of breast cancer. Data focusing on MpBC are limited. The aim of this study was to describe the clinicopathological features of MpBC and evaluate the prognosis of patients with MpBC. Eligible articles about MpBC were identified by searching CASES SERIES gov and the MEDLINE bibliographic database for the period of 1 January 2010 to 1 June 2021 with the keywords metaplastic breast cancer, mammary gland cancer, neoplasm, tumor, and metaplastic carcinoma. In this study, we also report 46 cases of MpBC stemming from our hospital. Survival rates, clinical behavior, and pathological characteristics were analyzed. Data from 205 patients were included for analysis. The mean age at diagnosis was 55 (14.7) years. The TNM stage at diagnosis was mostly stage II (58.5%) and most tumors were triple negative. The median overall survival was 66 (12-118) months, and the median disease-free survival was 56.8 (11-102) months. Multivariate Cox regression analysis revealed that surgical treatment was associated with decreased risk of death (hazard ratio 0.11, 95% confidence interval 0.02-0.54, p = 0.01) while advanced TNM stage was associated with increased risk of death (hazard ratio 1.5, 95% confidence interval 1.04-2.28, p = 0.03). Our results revealed that surgical treatment and TNM stage were the only independent risk factors related to patients' overall survival.

Low-grade adenosquamous carcinoma of the breast: a clinical, morphological and immunohistochemical analysis of 25 patients

AIMS

Due to its rarity and non-specific clinical and pathological features, low-grade adenosquamous carcinoma (LGASC) of the breast continues to pose diagnostic challenges. Unlike other triple-negative breast carcinomas, LGASC tends to have an indolent clinical behaviour. It is essential to recognise this lesion for accurate diagnosis and appropriate management.

METHODS AND RESULTS

Twenty-five cases of LGASC were identified in our archives and collaborating institutes. Cases of LGASC with dominant coexisting other type carcinomas were excluded. We studied the clinical presentation, morphological features, patterns of the commonly used immunohistochemical stains and follow-up. In our cohort, LGASC was commonly located at the outer aspect of the breast and associated with intraductal papilloma. The morphology of LGASC is characterised by infiltrating small glands and nests with variable squamous differentiation. We also found cuffing desmoplastic (fibrolamellar) stromal change in 75% of patients and peripheral lymphocytic aggregates in 87.5% of patients. P63 and smooth muscle myosin (SMM) were the most common myoepithelial markers used to assist in diagnosis. P63 often stained peripheral tumour cells surrounding invasive glands (circumferential staining in 80% of the cases), mimicking myoepithelial cells. It also stained the small nests with squamous differentiation. However, SMM was negative in 63% of the cases. The vast majority of our cases were triple-negative; only a few had focal and weak expressions of ER and PR. One patient who did not have excision developed lymph node metastasis. Most patients underwent excision or mastectomy with negative margins as surgical treatment; there were no recurrences or metastases in these patients with clinical follow-ups up to 108 months.

CONCLUSIONS

LGASC has some unique, although not entirely specific, morphological features and immunohistochemical staining patterns. Fibrolamellar stromal change, peripheral lymphocytic aggregates and variable staining of p63 and SMM are valuable features to facilitate the diagnosis.

Adenosquamous Carcinoma of the Breast: Case Report and Literature Review

Low-grade adenosquamous breast carcinoma (LGASC) is an atypical variant of metaplastic breast cancer. It differs from metaplastic carcinoma and has an indolent behavior. It usually presents as a palpable lump, unlike in our case, which had an incidental presentation. Because of its rarity, it often creates a clinical and diagnostic challenge. With the risk of local recurrence, the current management is aggressive with excision. Chemoradiation has been used in a few cases, but optimal management is unclear. Our manuscript aims to add to the existing knowledge on LGASC.

Adenosquamous carcinoma of the breast: a population-based study

Background

To summarize the clinicopathological characteristics, prognosis, and management of breast adenosquamous carcinoma (ASC).

Methods

A population-based study was performed using retrospectively extracted data from the Surveillance, Epidemiology, and End Results database for breast cancer patients with histological diagnoses of ASC, infiltrating duct carcinoma (IDC) and squamous cell carcinoma (SCC) from 2004 to 2016.

Results

ASC presented similar tumor size but low histological grade and less lymph node metastasis compared to IDC. ASC expressed less positive rate of hormone receptors and barely HER2, which was similar with SCC. ASC patients underwent the similar surgical and systematic treatment as IDC, only with less radiotherapy. Median follow-up data of 78 months showed that the prognosis of IDC patients was better than that of ASC patients (all p < 0.05 for BCSM and OS). ASC was not an independent prognosis factor of breast cancer. After propensity score matching (PSM), no significant difference in BCSM nor OS was observed between ASC and IDC groups. In HR-negative patients, the prognosis of ASC was similar with that of IDC, and both were superior to SCC. In HR-positive patients, the 5-year survival rate of ASC was 63.5%, which was far less than that in ASC of HR-negative (81.0%). Multivariate analysis showed that older age (age > 60) and advanced AJCC-stage were independent factors of poor prognosis in ASC, breast-conserving surgery was also ideally suited for ASC.

Conclusions

ASC has unique clinicopathological characteristics and prognosis. It is imperative to focus on a more precise and personalized treatment management of ASC patients.

A Case of Squamous Cell Carcinoma of the Breast with Low-Grade Adenosquamous Carcinoma

A 68-year-old woman with a breast mass was referred to our hospital. Imaging studies showed an oval well-defined mass, 1.3 cm in size, in her left lower outer quadrant of the breast. Core needle biopsy with immunohistochemical staining showed atypical spindle cells forming solid nests with necrosis and papillary lesions, leading to the tentative and pre-operative diagnosis of invasive ductal carcinoma. Due to the absence of daughter nodules, extensive ductal spread, and lymphadenopathy on imaging evaluation, the patient underwent breast-conserving surgery and sentinel node biopsy, resulting in negative surgical margins and no lymph node involvement. Post-operative pathological examination showed triple negative atypical cells with squamous differentiation, squamous cell carcinoma (SCC), with cystic parts and a small amount of low-grade adenosquamous cell carcinoma (LGASC), both encompassing the cystic parts in a contiguous fashion. No cases with synchronous SCC and LGASC in the breast have been reported to date. An etiologic correlation between SCC and LGASC should be further evaluated.