Bradley Busebee, MD, Daniela Guerrero Vinsard, MD, Clarissa E. Jordan, MD, Roger Moreira, MD, Robert Kraichely, MD Mayo Clinic, Rochester, MN
Introduction: Metastasis of breast cancer to the GI tract is rare and diagnostically challenging. We present a case of metastatic breast cancer causing rectal outlet obstruction.
Case Description/Methods: A 47-year-old woman with a history of ER, PR positive invasive lobular carcinoma (ILC) status post chemotherapy and bilateral mastectomy. She presented two years after curative treatment with fecal impaction and nausea refractory to routine laxative regimens. Endoscopy with biopsy revealed rectal stenosis and chronic inflammation. CT demonstrated circumferential rectal thickening and perirectal inflammation. Imaging and biopsies demonstrated bony metastasis of ILC. The bony lesions were FDG avid on PET, the rectal lesion was not. She was managed for recurrent cancer.
Despite aggressive laxative regimen for maintenance of liquid stools, her severe constipation persisted. Repeat imaging and endoscopy two years later revealed persistent rectal thickening on MR proctogram (Fig. 1a) and inflamed mucosa consistent with prior reports (Fig. 1b). Endoscopic ultrasound was planned for deeper imaging and tissue sampling. However, repeat rectal mucosal biopsy showed definitive metastasis of ILC (Fig. 1c). The patient returned to her oncologist for management.
Discussion: Metastasis of breast cancer to GI luminal sites is quite rare. Lobular carcinoma accounts for a minority of breast cancer but a relatively large proportion of GI metastasis from breast cancer1. The radiologic and histologic characteristics of ILC often complicate diagnosis. ILC can be dispersed throughout the mucosa and deeper luminal tissue. Superficial biopsies of the mucosa may be inadequate1. PET is also less sensitive for ILC metastasis compared to more common breast cancer types2. Metastatic ILC can also be mistaken for primary gastrointestinal carcinomas on pathology though a few cell markers are reliable for this discrimination (Fig 1c). All of these nuances were consequential in the above case. Practitioners who may encounter similar GI complaints in patients with prior ILC should consider metastatic disease even with negative biopsy and PET, especially in presence of bowel wall thickening. This may allow more rapid detection and management of GI metastasis.
Figure: 1a. MR proctogram demonstrating marked circumferential thickening of the rectal wall to the level of the sigmoid colon, limiting rectal compliance and volume. 1b. Rectum with erythematous mucosa without any apparent erosion or ulceration. Not pictured is the associated sharp angulation at the sigmoid colon. 1c. Rectal mucosal biopsy with immunohistochemistry. Neoplastic cells were positive for CK7 (left), GATA-3 (middle), mammaglobin (right), CK7, ER, and GCDFP-15, while negative for CK20, CDX2, TTF-1, PAX8, and p40, consistent with a metastatic carcinoma of breast primary. Original magnification 200x.
Bradley Busebee indicated no relevant financial relationships.
Daniela Guerrero Vinsard indicated no relevant financial relationships.
Clarissa Jordan indicated no relevant financial relationships.
Roger Moreira indicated no relevant financial relationships.
Robert Kraichely indicated no relevant financial relationships.
Bradley Busebee, MD, Daniela Guerrero Vinsard, MD, Clarissa E. Jordan, MD, Roger Moreira, MD, Robert Kraichely, MD. P2310 - Rectal Obstruction in a Patient With Metastatic Invasive Lobular Carcinoma of the Breast, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.