Surreal illustration of breast tissue with subtle gastric cancer cells.

Rare Case: When Breast Lumps Aren't Always What They Seem

Reese Marlowe in Health & Wellness November 2025 • 4 min read.

"Unveiling the Unusual: A Gastric Cancer Masquerading as Normal Breast Tissue"

Breast metastases from cancers originating outside the breast are rare. While metastatic lesions can show diverse radiological features, instances where they mimic normal breast tissue on ultrasound are even less common. This diagnostic challenge can lead to delays in treatment and poorer outcomes for patients.

Several studies highlight the high negative predictive value of combined normal ultrasound and mammography findings when a palpable lump is present. This means that if both imaging tests appear normal, the likelihood of cancer is low. However, follow-up is still recommended, especially if the physical examination raises suspicion. This recommendation acknowledges the limitations of imaging and the importance of clinical judgment.

This article presents a case of a 26-year-old woman with breast metastasis from a known gastric adenocarcinoma. Her initial mammogram and ultrasound showed no suspicious features, highlighting the potential for metastatic breast cancer to evade early detection. This case underscores the need for heightened awareness and comprehensive evaluation in patients with a history of cancer.

The Case: A Diagnostic Puzzle

Surreal illustration of breast tissue with subtle gastric cancer cells.

A 26-year-old woman, previously treated for gastric adenocarcinoma with peritoneal seeding metastasis, was referred for evaluation of a palpable lump in her left upper-inner breast. She had been undergoing chemotherapy for the past year. Her medical history was notable for the absence of any prior breast imaging or gynecological malignancies, and there was no family history of breast or gynecological cancer. The physical examination revealed an irregular, lumpy growth with tenderness at the 10 o'clock position. No axillary or supraclavicular lymph nodes were palpable.

Initial ultrasound examinations showed normal fibroglandular tissue with heterogeneous echotexture and no evidence of an abnormal mass lesion. The findings were symmetric with the corresponding area of the contralateral breast. Due to the negative imaging findings despite the palpable lump, digital mammograms were performed. The breast tissue was extremely dense, with no definite areas of mass lesions or microcalcifications. The challenge lay in distinguishing between normal tissue variations and subtle signs of malignancy.

Initial Assessment: Normal ultrasound, dense breast tissue on mammogram.
Follow-Up: Palpable lump enlarged within a month, prompting a repeat ultrasound.
Key Finding: Targeted ultrasound revealed heterogeneous echotexture with large areas of decreased echogenicity and skin thickening.
Lymph Node Involvement: Ipsilateral axillary lymph node showed eccentric cortical thickening.
Confirmation: Ultrasound-guided core needle biopsy confirmed adenocarcinoma, consistent with metastasis from the stomach.

Despite undergoing several cycles of chemotherapy with paclitaxel and cisplatin, the patient's condition deteriorated, and she passed away one year later. This outcome highlights the aggressive nature of metastatic cancer and the challenges in achieving long-term remission.

The Importance of Vigilance

This case serves as a crucial reminder that breast metastasis from extramammary malignancies can sometimes mimic normal breast tissue on sonography. In patients with a history of cancer and a palpable breast lesion, clinicians should maintain a high index of suspicion. Prompt tissue sampling is essential when physical examination findings raise concerns, irrespective of negative sonographic and mammographic results. Continued research and awareness are necessary to improve early detection and outcomes in such challenging cases.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.3348/jksr.2015.73.6.393, Alternate LINK

Title: Breast Metastasis From Gastric Adenocarcinoma Mimicking Normal Breast Parenchyma On Ultrasound: A Case Report

Subject: Radiology, Nuclear Medicine and imaging

Journal: Journal of the Korean Society of Radiology

Publisher: The Korean Society of Radiology

Authors: Jihyun Lee, Jin Hwa Lee, Min Kyoung Park, Young Mi Park, Dae Cheol Kim, Miri Lee, Se Heon Cho

Published: 2015-01-01

Everything You Need To Know

How often do cancers from outside the breast spread to the breast, and what makes them hard to spot?

Breast metastases from cancers originating outside the breast are rare, particularly when they mimic normal breast parenchyma on ultrasound. This can lead to significant diagnostic challenges, potentially delaying appropriate treatment and worsening patient outcomes. Instances where metastatic lesions resemble normal breast tissue on ultrasound make detection more difficult. The high negative predictive value of combined normal ultrasound and mammography findings may provide false assurance, especially when a palpable lump is present.

Can you describe the diagnostic journey of the 26-year-old woman in the case, from initial presentation to final diagnosis?

A 26-year-old woman with a history of gastric adenocarcinoma presented with a palpable lump in her left breast. Initial imaging, including mammogram and ultrasound, showed no suspicious features, resembling normal fibroglandular tissue. Further investigation, prompted by the persistence and enlargement of the lump, revealed heterogeneous echotexture and skin thickening on targeted ultrasound. A biopsy confirmed adenocarcinoma, consistent with metastasis from the stomach. Despite chemotherapy, the patient's condition deteriorated, and she passed away one year later.

In patients with a cancer history, what level of suspicion should clinicians have for breast metastasis, and what steps should they take if they find a lump?

Clinicians should maintain a high index of suspicion for breast metastasis from extramammary malignancies in patients with a history of cancer who present with a palpable breast lesion. Prompt tissue sampling, such as a core needle biopsy, is essential when physical examination findings raise concerns, irrespective of negative sonographic and mammographic results. This vigilance is crucial because metastatic breast cancer can sometimes mimic normal breast tissue on sonography, delaying diagnosis and treatment.

What does the case reveal about the limitations of relying on imaging, like mammograms and ultrasounds, and the importance of clinical judgment?

The case highlighted the limitations of relying solely on imaging techniques like mammography and ultrasound, especially when physical examination findings raise suspicion. Despite initial normal imaging results, the palpable lump in the patient's breast warranted further investigation due to her history of gastric adenocarcinoma. This case emphasizes the importance of integrating clinical judgment with imaging findings to avoid delays in diagnosing metastatic breast cancer. The initial assessment showed normal ultrasound and dense breast tissue on mammogram.

What does this case indicate about the aggressive nature and the challenges of treating metastatic cancer, even with chemotherapy?

The case of the 26-year-old woman underscores the aggressive nature of metastatic cancer and the challenges in achieving long-term remission. Despite undergoing chemotherapy with paclitaxel and cisplatin, the patient's condition deteriorated, leading to her death within a year. This outcome highlights the need for continued research and awareness to improve early detection and outcomes in such challenging cases. It also demonstrates the potential for aggressive disease progression despite treatment efforts, emphasizing the importance of early and accurate diagnosis.