Invasive mucinous carcinoma of the breast

Area of Science:

• Oncology
• Radiology
• Pathology

Background:

• Mucinous carcinoma of the breast is a rare subtype, comprising 1-7% of all breast cancers.
• It generally presents with a better prognosis and lower metastatic potential compared to other invasive breast carcinomas.
• Typical imaging findings include lobulated, well-circumscribed masses on mammography, sonography, and MRI.

Purpose of the Study:

• To report an atypical case of mucinous carcinoma.
• To describe a unique presentation of intramammary lymph node metastasis from an occult breast primary.
• To highlight the diagnostic challenges and findings in a mixed mucinous neoplasm with a micropapillary pattern.

Main Methods:

• Review of a clinical case presentation.
• Analysis of imaging findings from mammography, sonography, and gadolinium-enhanced MRI.
• Histopathological examination of percutaneous biopsy specimens.

Main Results:

• A palpable intramammary lymph node was identified as a metastasis from an unknown breast primary.
• Imaging studies revealed findings consistent with a mucinous neoplasm.
• Biopsy confirmed a mixed mucinous neoplasm with a micropapillary pattern.

Conclusions:

• Mucinous breast carcinoma can present atypically, including with isolated intramammary lymph node metastasis.
• Advanced imaging and histopathology are crucial for diagnosing unusual presentations of mucinous neoplasms.
• This case underscores the importance of considering rare presentations even in generally prognostically favorable cancer types.