A case study of a woman, with both breast cancer and sarcoidosis in her breast lymph nodes, highlights the difficulties in distinguishing between these two conditions.
The report, “Sarcoidosis imitating breast cancer metastasis: a case report and literature review,” published in the journal Cancer Biology & Medicine, also again calls attention to an apparent link between sarcoidosis and cancer.
The sarcoidosis-cancer connection has been described by physicians in numerous studies, but proof of a relationship is not considered established. An earlier study of 2,544 sarcoidosis patients found that lymphomas were 11-fold more common in these people than in the general population, and lung cancer was three times as likely to occur.
In another study of 21 patients who developed sarcoidosis after cancer, 10 had been treated for breast cancer. Other studies report similar findings.
Physicians at the Russian Cancer Research Center in Moscow described a woman who sought care at their hospital after discovering a lump in her left breast. A physical examination and mammography scan confirmed an abnormal tissue mass.
An ultrasound examination also showed that several lymph nodes in the area were larger than normal. A needle biopsy revealed that the lump contained abnormal cells, and doctors performed a lymph biopsy to confirm the diagnosis, and to classify the tumor.
To their surprise, they did not find tumor cells in the lymph tissue. Instead, the lymph node contained granulomas. At this point, the team decided to surgically remove the lump, and analyze the surrounding tissue.
It turned out that the lump was indeed a cancer, which was classified as a non-luminal HER-2 and neu-positive tumor. In addition, the doctors found noncaseating epithelioid cell granulomas, indicating sarcoidosis in six of the 15 lymph nodes analyzed. The lymph nodes showed no signs of cancer.
Although positron emission tomography, or PET, is one of the most advanced and precise methods to diagnose breast cancer, the team noted that the technique is not able to distinguish between a tumor and sarcoidosis-affected tissue. When the two diseases are co-occurring, the only way to assess the spread of each one is to analyze the tissue under the microscope.
“This case report emphasizes the importance of differential diagnosis of lymph node involvement in cancer patients,” they concluded. “Although several epidemiological studies reported the association between cancer and sarcoidosis, further studies, including case reports, may represent an opportunity to obtain additional biological and clinical information to clarify the mechanisms underlying the association of cancer and sarcoidosis.”