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

[Rare tumours of the breast]

Breast tumours are the most common tumours in women but represent a very heterogeneous group. On the one hand, there are ductal and lobular carcinomas of the breast, representing 90% of tumours, whose clinicopathologic characteristics are well known. On the other hand, there are rare breast tumours, each of which represents less than 1% that limits their study through large cohorts. The objective of this work was to collect, update and synthesize knowledge on these rare tumours. A literature review was performed on the Medline and Google Scholar databases. We present here a selection of several rare tumours, providing updated data at the epidemiological, histopathological, genetic, clinical and radiographic, prognostic and therapeutic levels, taking into account the place of radiotherapy. Each tumour histology is unique and has its own characteristics, the management must therefore be adapted as much as possible and decided in a multidisciplinary meeting.

Oncological outcomes for encapsulated papillary carcinoma of the breast: Multicentric study of Turkish Society for Radiation Oncology breast cancer study group (TROD 06-014 study)

BACKGROUND

Encapsulated papillary carcinoma (EPC) is a rare malignant papillary breast cancer accounting for approximately .5%-2% of all breast tumors. The aim of this multicenter study was to evaluate clinicopathologic features of EPC in addition to oncological outcomes and radiotherapy (RT) details.

METHODS

From 10 different academic hospitals in Turkey, we obtained pathology reports of 80 patients with histologically confirmed EPC between 2005 and 2022. Demographic, diagnostic, and treatment data were collected from medical records, retrospectively. Local failure, distant progression, toxicity-adverse effects, overall survival (OS), and disease-free survival were evaluated, and survival analyzes were performed using the Kaplan-Meier method.

RESULTS

Eighty patients with the diagnosis of misspelled sorry (ECP) were retrospectively evaluated. The median age of the patients was 63 (range, 35-85). After a median follow-up of 48 (range; 6-206) months, local recurrence was observed in three patients (4%). Local recurrence was less common in the patients who received whole breast RT with a tumour bed boost (p = .025). There were not any distant metastasis or disease-related death. RT was applied to 61% of the cases, and no treatment-related grade 3 or higher toxicity was reported in any of the patients. Five year OS, cancer-specific survival (CSS), and  were observed as 85%, 100%, and 96%, respectively.

CONCLUSIONS

ECP is a rare, slow-progressing breast carcinoma associated with good prognosis, it is a disease of elderly patient, and usually occurs in postmenopausal women. It responds extremely well to optimal local treatments and appropriate adjuvant treatments on a patient basis, and has excellent OS and CSS ratios.

Encapsulated papillary carcinoma of the breast: A single institution experience

Encapsulated papillary carcinoma (EPC) is a relatively rare form of breast cancer. To date, no evidence-based guidelines for the treatment of EPC have been established. Between January 2015 and December 2021, patients with histologically confirmed EPC of the breast were recorded in a database by The Third Hospital of Nanchang City (Nanchang, China). A total of 46 patients with EPC were retrieved from the database. Age at diagnosis ranged from 41-88 years (median age, 62 years). A total of 21 of these patients had pure EPC, 6 patients had EPC associated with ductal carcinoma in situ and 19 patients had EPC associated with invasive carcinoma. The majority of EPC cases were low nuclear grade, hormone receptor-positive and human epidermal growth factor receptor-2-negative. Additionally, myoepithelial cells were always absent in the papillae of the EPC. All patients underwent lumpectomy or mastectomy with sentinel lymph node biopsy, and almost all of the patients received adjuvant hormonal therapy. Adjuvant chemotherapy was only suggested to 4 patients who were diagnosed with axillary lymph node involvement. Subsequently, the clinicopathological features of non-invasive EPC were compared with invasive EPC. The results indicated that larger tumor sizes and axillary lymph node metastases were more common in invasive tumors. During the follow-up, only 2 patients with invasive EPC experienced recurrence or metastasis. In conclusion, a substantial proportion of invasive EPC cases display aggressive characteristics and metastatic potential, despite it being considered a subtype of carcinoma in situ with excellent prognosis, and local surgical resection is the initial method of treatment. Therefore, adjuvant endocrine therapy, radiotherapy and chemotherapy should be considered in select patients, especially in those diagnosed with invasive EPC tumors.

Contrast-enhanced ultrasound combined with ultrasonic elastography to diagnose encapsulated papillary carcinoma: A case report

Encapsulated papillary carcinoma is a rare malignant breast tumor with low malignancy, and is most commonly found in postmenopausal women. On ultrasound, encapsulated papillary carcinoma has an envelope, and anechoic areas inside the lesion. Contrast-enhanced ultrasound shows marked enhancement without size expand, and ultrasonic elastography suggests soft parenchyma in the lesion. However, it is often challenging to differentiate between encapsulated papillary carcinoma and other breast tumors, especially some benign lesions. Here, we reported a case of encapsulated papillary carcinoma in a 65-year-old female patient who discovered a breast mass three years ago and presented with nipple discharge and pain six months before. This case report demonstrated the ability of multimodal ultrasound to diagnose encapsulated papillary carcinoma.

A Case Report on Apocrine Encapsulated Papillary Carcinoma of the Breast with Frank Invasion: A Diagnostic Quandary

Encapsulated papillary carcinoma is a special type of breast cancer defined in the fifth edition of the World Health Organization breast tumor classification guidelines. Apocrine encapsulated papillary carcinoma is extremely rare, and only 10 cases have been described previously. We encountered a case of apocrine encapsulated papillary carcinoma with frank invasion. The patient was a 77-year-old woman with a painless mass in her right breast. Core needle biopsy revealed that the tumor cells had voluminous eosinophilic cytoplasm and enlarged nuclei with prominent nucleoli. We diagnosed this lesion as carcinoma with apocrine differentiation and suggested the possibility of an encapsulated papillary carcinoma. The patient underwent a right-sided mastectomy. Gross examination of the resected specimen revealed a multilobulated tumor. Microscopically, the tumor cells, which had voluminous eosinophilic cytoplasm and enlarged nuclei with prominent nucleoli, proliferated in papillary fashion with fibrous stalks in the cystic space. Myoepithelial cells were not observed around the cystic space. Frank invasion was also observed around the encapsulated papillary carcinoma. Immunohistochemistry analysis revealed that the tumor cells were negative for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 and positive for androgen receptor and gross cys­tic disease fluid protein 15. Based on these findings, we diagnosed this lesion as an apocrine encapsulated papillary carcinoma with frank invasion.

Encapsulated Papillary Carcinoma: A Case Report and Review of the Literature

Papillary neoplasms are a distinct assemblage of breast lesions whose main characteristic is the presence of fibrovascular cores which are surrounded by epithelial cells. Papillary lesions are of heterogenous nature, with similar clinical behavior and histomorphologic characteristics. Their biological patterns, however, can be quite different. According to the World Health Organization (WHO) (2019), breast tumors have been recently classified into five subdivisions of papillary neoplasms. They are namely: intraductal papilloma, papillary ductal carcinoma in situ, encapsulated papillary carcinoma (EPC), solid-papillary carcinoma and invasive papillary carcinoma. Despite the papillary architecture being easily recognized, histological variations are diagnostically challenging. The presence or absence of myoepithelial cells in the papillary cores can distinguish the malignant from the benign lesions respectively. EPC is a rare, histologically unique carcinoma type whose main characteristic is a thick fibrous capsule at the periphery and a prolific cell structure with fibrovascular stalk support. A characteristic feature is the absence of myoepithelial cells at the surrounding thick fibrous capsule. Usually, EPC maintains a slowly developing tumor despite the absence of myoepithelial cells. An EPC case presents diagnostic difficulties since it bears close resemblance to malignant and benign papillary breast lesions. Upon a clinical and radiological evaluation, EPC commonly appears as a benign lump. In mammography, the tumor is frequently found in a retroareolar position as a well-defined mass. On the other hand, in an ultrasound, the tumor will appear as a cystic lesion characterized by solid components. The clinical picture of EPC is usually an asymptomatic benign mass which at times can be felt through auto-palpation or screening mammography. A bloody nipple discharge is regarded as a common symptom. We report a case of an EPC of a 81-year-old woman who presented with a mass in the left breast.

Encapsulated Papillary Carcinoma of Breast: Clinicopathological Features and Prognostic Parameters

Introduction Encapsulated papillary carcinoma (EPC) is a rare malignant papillary breast tumor that, despite a lack of distinct myoepithelial layer, is considered an in situ carcinoma unless associated with a frank invasive component. Data regarding clinicopathologic features of rare breast tumors like EPC are especially scarce. Therefore, in this study, we evaluated the clinicopathologic features of EPC and performed a clinicopathological comparison with conventional invasive ductal carcinoma (IDC). Methods It was a retrospective study conducted in the Department of Pathology, Liaquat National Hospital and Medical College, from January 2013 to December 2019 over a period of seven years. During this period, 16 cases were diagnosed as EPC, and 634 cases were labeled as IDC. Estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2/neu) immunohistochemical (IHC) stains were performed on both EPC and IDC cases. Moreover, myoepithelial IHC stains were performed on all cases of EPC. Clinicopathologic features of EPC were compared with IDC. Results The mean age of the EPC patients was 51.81±13.94 years, with a mean tumor size of 2.97±2.46 cm. The majority of cases were grade II, and axillary metastasis was present in 18.8% of cases. About 56.3% of cases were in situ, and 43.8% showed foci of invasion in the form of IDC. Recurrence was noted in 12.5% of cases with a survival rate of 93.8%. ER, PR, and HER2/neu positivity was noted in 81.3%, 75%, and 12.5% cases, respectively. EPC was significantly noted to have lower tumor grade and pathological T-stage than IDC. Similarly, a lower frequency of axillary metastasis was noted in EPC than IDC.  Conclusion EPC is a rare distinct subtype of papillary breast tumors with overall good survival and low recurrence rate. Compared to IDC, we found EPC to be associated with better prognostic parameters such as lower tumor grade and T-stage and lower frequency of axillary metastasis.