Recommended Citation
Pekarek SA, Chandrashekar A, Attasi MB, Klosterman EE, Albright J. A Rare Case of Primary Breast Merkel Cell Carcinoma in a Male Gendered Patient. Presented at Scientific Day; May 20, 2026; Milwaukee, WI.
Abstract
Introduction/Background:
Merkel cell carcinoma (MCC) is an aggressive, rare neuroendocrine tumor, typically arising in the skin. However, there are few documented cases of neuroendocrine tumors of breast parenchyma with Merkel cell differentiation. This accounts for less than 0.1% of all breast cancers with almost all cases being described in females.
Description:
We present here a 62-year-old, immunocompetent, Hispanic male with a palpable and painful right sided breast mass, present for three to four months. On the exam, a four-centimeter mass was palpated in the 9 o’clock region of the right breast without associated skin nodularity or dermal attachment. Diagnostic mammography revealed a large irregular mass, with follow up ultrasound-guided core needle biopsy resulting in a high-grade carcinoma with neuroendocrine differentiation and immunostaining favoring Merkel cell carcinoma. Staging work-up with PET CT showed no metastatic disease. The patient underwent a right breast wide-local excision with a sentinel lymph node procedure.
Discussion:
Final pathology revealed a 4.5-centimeter primary breast Merkel cell carcinoma without skin involvement, and all four sentinel lymph nodes were negative for carcinoma. For his Stage IIA (T2N0M0) disease, he will be undergoing adjuvant radiotherapy. Not only is current literature regarding Merkel cell carcinoma of the breast parenchyma extremely limited, but it is also incredibly rare to be found in the male gender. There has only been two other reported case of a male patient developing primary breast parenchymal Merkel cell carcinoma. Awareness of this rare pathology, especially in an atypical population, is important to prevent misleading or delayed diagnosis and treatment.
Presentation Notes
Presented at Scientific Day; May 20, 2026; Milwaukee, WI.
Full Text of Presentation
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Document Type
Poster
Open Access
Available to all.
A Rare Case of Primary Breast Merkel Cell Carcinoma in a Male Gendered Patient
Introduction/Background:
Merkel cell carcinoma (MCC) is an aggressive, rare neuroendocrine tumor, typically arising in the skin. However, there are few documented cases of neuroendocrine tumors of breast parenchyma with Merkel cell differentiation. This accounts for less than 0.1% of all breast cancers with almost all cases being described in females.
Description:
We present here a 62-year-old, immunocompetent, Hispanic male with a palpable and painful right sided breast mass, present for three to four months. On the exam, a four-centimeter mass was palpated in the 9 o’clock region of the right breast without associated skin nodularity or dermal attachment. Diagnostic mammography revealed a large irregular mass, with follow up ultrasound-guided core needle biopsy resulting in a high-grade carcinoma with neuroendocrine differentiation and immunostaining favoring Merkel cell carcinoma. Staging work-up with PET CT showed no metastatic disease. The patient underwent a right breast wide-local excision with a sentinel lymph node procedure.
Discussion:
Final pathology revealed a 4.5-centimeter primary breast Merkel cell carcinoma without skin involvement, and all four sentinel lymph nodes were negative for carcinoma. For his Stage IIA (T2N0M0) disease, he will be undergoing adjuvant radiotherapy. Not only is current literature regarding Merkel cell carcinoma of the breast parenchyma extremely limited, but it is also incredibly rare to be found in the male gender. There has only been two other reported case of a male patient developing primary breast parenchymal Merkel cell carcinoma. Awareness of this rare pathology, especially in an atypical population, is important to prevent misleading or delayed diagnosis and treatment.
Affiliations
Advocate Christ Medical Center