Mammary mucinous cystadenocarcinoma with long-term follow-up: molecular information and literature review

Abstract

Background Mucinous cystadenocarcinoma (MCA) is a very rare form of breast cancer that was first described in 1998. Only 33 cases of primary MCA, including our present case, have been reported thus far. As a consequence, its molecular features, prognosis and treatment regimen are poorly known. Here, we describe a less common presentation of MCA, detail its molecular features, discuss the major differential diagnosis, and provide a brief review of the literature. Case presentation A 59-year-old woman presented with a breast lump in which mammography showed a well-defined nodule. Core needle biopsy (CNB) revealed several lesions lined by tall columnar cells with stratification and abundant mucinous secretion; excision was recommended for final diagnosis. The resected specimens showed cavities of different sizes without surrounding myoepithelial cells. The cavities were rich in mucus, and the nuclei were located at the base of the cells, containing intracellular mucus. Immunohistochemical analysis revealed that it was triple-negative breast cancer (TNBC). Next-generation sequencing (NGS) revealed pathogenic mutations in the PIK3CA, KRAS, MAP2K4, RB1, KDR, PKHD1, TERT, and TP53 genes. A diagnosis of MCA was rendered. The patient has been followed up for 108 months to date and showed no signs of recurrence or metastasis. Conclusion Our study presents the gene profile of an MCA case with no recurrence or metastatic tendency after 108 months of follow-up, and a review of the literature helps us better understand the clinical, pathologic, and molecular features of this tumor.

Mucinous Cystadenocarcinoma of the Breast with Bone Metastases: First Case Report and Literature Review

“…The extravasation of mucin into the adjacent interstitial tissue is considered a constant feature of breast MCA [4-6, 10, 12, 13, 15, 22, 25-32]. Additionally, in 15 cases (including ours), tumor cells were observed floating singly or in clusters in the mucin, resembling typical breast mucinous carcinoma [4,6,12,13,15,22,[25][26][27][28][30][31][32]. There were 20 cases of ductal carcinoma in situ (DCIS), with or without mucin production, favoring primary carcinoma over metastasis [4-7, 9, 13, 15, 16, 18, 19, 22, 24, 25, 27-31].…”

“…The age of onset of breast MCA has been reported as 41–96 years (average: 61.6 years), and most cases occur in those aged >60 years [3‒32]. The majority of cases of breast MCA were detected early or were locally advanced.…”

Primary Mucinous Cystadenocarcinoma of the Breast Intermixed with Pleomorphic Invasive Lobular Carcinoma: The First Report of This Rare Association

“…Mucinous cystadenocarcinoma (MCA) is an extremely rare variant of invasive breast carcinoma usually presenting as a large (up to 19 cm) multicystic mass, arising in postmenopausal women (average 58 years old) [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ]. As a distinct and well-documented entity, it has been introduced in the recent 5th edition of WHO classification of tumors of the breast, 2019 [ 32 ].…”

“…First described by Koenig C. and Tavassoli in 1998, MCA of the breast is typically characterized by microscopic cystic spaces lined with bland-appearing tall columnar cells with abundant intracytoplasmic and extracytoplasmic mucin; stratification, tufting and papillary formations are also a common feature [ 2 ]. The degree of nuclear cytological atypia can vary, with focal loss of mucinous secretion and transformation in eosinophilic/squamoid cells [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ]. Immunohistochemistry often results in a triple negative immunophenotype; however, the prognosis is generally favorable and nodal metastases are unusual [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ,…”

“…The degree of nuclear cytological atypia can vary, with focal loss of mucinous secretion and transformation in eosinophilic/squamoid cells [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ]. Immunohistochemistry often results in a triple negative immunophenotype; however, the prognosis is generally favorable and nodal metastases are unusual [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , …”