Encapsulated papillary carcinoma associated with mucinous carcinoma in the male breast: a case report
- 1Department of Anatomical Pathology, Chiangrai Prachanukroh Hospital, Chiang Rai, Thailand
Abstract
Introduction and importance:: Male breast cancer is rare, accounting for less than 1% of breast cancer cases. The coexistence of encapsulated papillary carcinoma (EPC) and mucinous carcinoma in the same male breast is exceptionally rare.
Case presentation:: A 55-year-old man presented with a long-standing right breast mass. Imaging revealed a subareolar lesion classified as BI-RADS 4C. Histologically, two adjacent tumors separated by a thin fibrous band showed the characteristic features of mucinous carcinoma and EPC. Myoepithelial markers (p63 and SMMS1) were absent within the papillae and at the tumor periphery, supporting EPC. Both components were estrogen receptor- and progesterone receptor-positive and human epidermal growth factor receptor 2-negative, with a low Ki-67 index. No lymph node metastasis was identified (pT2N0).
Clinical discussion:: The coexistence of EPC and mucinous carcinoma in the same male breast is extremely rare and, to our knowledge, has not been previously reported. The distinct histopathological features and immunohistochemical profiles of the two components support their classification as separate tumor entities. However, their close anatomical association raises the possibility of a common neoplastic origin, although the precise histogenetic relationship remains uncertain.
Conclusion:: This case highlights the diagnostic complexity of this rare tumor combination and the importance of careful morphological and immunohistochemical evaluation.
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BibTeX
@article{tragoolwananon2026encapsulated,
title = {{Encapsulated papillary carcinoma associated with mucinous carcinoma in the male breast: a case report}},
author = {Vimpattra Tragoolwananon},
journal = {International Journal of Surgery Case Reports},
year = {2026},
month = sep,
doi = {10.1097/rc9.0000000000001071},
url = {https://doi.org/10.1097/rc9.0000000000001071},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - Encapsulated papillary carcinoma associated with mucinous carcinoma in the male breast: a case report
AU - Vimpattra Tragoolwananon
PY - 2026
DA - 2026/09/29
JO - International Journal of Surgery Case Reports
DO - 10.1097/rc9.0000000000001071
UR - https://doi.org/10.1097/rc9.0000000000001071
AB - Introduction and importance:: Male breast cancer is rare, accounting for less than 1% of breast cancer cases. The coexistence of encapsulated papillary carcinoma (EPC) and mucinous carcinoma in the same male breast is exceptionally rare. Case presentation:: A 55-year-old man presented with a long-standing right breast mass. Imaging revealed a subareolar lesion classified as BI-RADS 4C. Histologically, two adjacent tumors separated by a thin fibrous band showed the characteristic features of mucinous carcinoma and EPC. Myoepithelial markers (p63 and SMMS1) were absent within the papillae and at the tumor periphery, supporting EPC. Both components were estrogen receptor- and progesterone receptor-positive and human epidermal growth factor receptor 2-negative, with a low Ki-67 index. No lymph node metastasis was identified (pT2N0). Clinical discussion:: The coexistence of EPC and mucinous carcinoma in the same male breast is extremely rare and, to our knowledge, has not been previously reported. The distinct histopathological features and immunohistochemical profiles of the two components support their classification as separate tumor entities. However, their close anatomical association raises the possibility of a common neoplastic origin, although the precise histogenetic relationship remains uncertain. Conclusion:: This case highlights the diagnostic complexity of this rare tumor combination and the importance of careful morphological and immunohistochemical evaluation.
SN - 2210-2612
ER -