Triple negative invasive lobular carcinoma of the breast presents as small bowel obstruction

A Rare Case of Triple-Positive Breast Cancer With Eventual Triple-Negative Small Bowel Metastasis

Invasive lobular breast cancer (ILBC) is a common cause of breast cancer. Prognosis is dependent on many factors such as metastasis location and hormone receptor positivity. A 59-year-old postmenopausal African-American female who was referred to our clinic in May of 2022 presented with a suspicious small bowel lesion seen on surveillance imaging. The patient was diagnosed 15 years prior, with hormone receptor triple positive ILBC of the left breast, T1N2M0. In March of 2021, the patient was admitted to the hospital for rectal bleeding and was also found to have an elevated carcinoembryonic antigen (CEA) level. Computed tomography of the abdomen and pelvis was performed, which revealed a 4 cm segment of proximal ileum that was indeterminate for inflammation, neoplasm, or focal ischemia. The patient ultimately agreed to proceed with a diagnostic laparoscopy to further identify this area and underwent a small bowel resection. The final pathology of this specimen revealed a poorly differentiated, diffuse-type carcinoma with a focal mucinous matrix. The tumor involved the submucosa, serosa, and pericolonic adipose tissue. The morphology was consistent with metastatic carcinoma originating from ILBC. The hormone receptors for this specimen revealed estrogen-receptor (ER) negative, progesterone-receptor (PR) negative, and human epidermal growth factor receptor-2 (HER-2) negative. Lobular breast cancer metastasis to the small bowel as well as triple positive to triple negative conversion is exceedingly rare. The recurrence and metastasis of breast cancer are considerably high and the survival rate for these individuals has shown little improvement throughout the last decade. Defining relevant prognostic markers is crucial for improved management with known metastasis and triple negative receptors.

Gastrointestinal Metastases From Lobular Breast Carcinoma: A Literature Review

Invasive lobular carcinoma (ILC) represents a rare subtype of breast carcinoma, originating from the lobule. Unlike ductal carcinoma, ILC does not express E-cadherin and thus can metastasize to uncommon sites. We aimed to investigate the clinicopathological characteristics of the rare subgroup of ILC patients with gastrointestinal (GI) metastases. A PubMed search was undertaken using the terms "Lobular Breast Carcinoma" AND "Gastrointestinal Metastasis." We identified 169 cases, with metachronous GI metastatic disease being approximately twice as common as synchronous GI metastases. The median age at initial diagnosis was 56.7 years (24-88). The majority of patients were hormonal receptor-positive and only a small minority was HER2-positive. The appearance of a gastrointestinal lesion was often the mode of revelation of ILC. Differential diagnosis from primary gastrointestinal cancer is sometimes challenging, especially in the case of signet-ring cell carcinoma. The median time from breast cancer diagnosis to GI metastases was 6.5 years (0-33). Most common metastatic sites include the stomach, colon, and rectum, in order of decreasing frequency, whereas metastases were found in every part of the digestive tract. In conclusion, metastases of ILC can arise in the gastrointestinal tract and they should be managed similarly to metastatic breast cancer.

To Identify Small Bowel Metastasis From Lobular Breast Cancer on 18 F-Fluoroestradiol PET/CT : Necessary to Adjust the Background Uptake Level

ABSTRACT

A 61-year-old woman was incidentally found to have small bowel metastasis from an undiagnosed lobular breast cancer in a workup for her acute presentation of small bowel obstruction. However, outside-hospital mammogram and breast ultrasound failed to reveal primary breast cancer. At 3.5 months postsurgery, the patient transferred her care to our hospital and received initial staging 18 F-fluoroestradiol (FES) PET/CT. The occult primary right breast cancer and previously biopsied right axilla lymph node were visualized on FES PET/CT. The intense small bowel uptake of FES was initially considered as physiological; however, after readjusting the background FES level on PET, an intense focus at small bowel anastomosis site became obvious.