Rectal Metastasis of Breast Carcinoma: Presentation of Two Cases

Introduction

Breast carcinoma is the most common malignancy in women, and is the leading cause of cancer-related mortality. ¹ Distant metastases are present in ∼ 11% of the patients at the time of diagnosis. The most common metastatic sites are lymph nodes, bone, lung, liver, and the central nervous system, whereas gastrointestinal (GI) tract involvement is rare. ² The aim of this article is to report the features of clinical presentation, diagnosis difficulties, and treatment modalities of 2 cases of rectal metastases from breast cancer.

Cases

Results

In Case 1, the chemotherapy was not well-tolerated; thus, the patient received only 4 cycles of the FEC regimen. Her general condition deteriorated, and she died in September 2011. In Case 2, the patient still receives zoledronic acid and tamoxifen. There is no evidence of relapse, and as of her last regular follow-up in November 2011, she was doing well.

Discussion

Metastatic disease originating from breast cancer usually involves lymph nodes, bone, lung, liver, or brain; however the involvement of GI tract is less commonly reported. In this location, the stomach has been more commonly reported to be involved, followed by the colon, whereas rectal involvement is less common. ¹ The real incidence of breast cancer metastatic to the GI tract is unclear. In an autopsy series, its frequency ranged from 8 to 12%. ³ The disease-free interval between primary breast cancer and GI involvement may range from synchronous presentation to as long as 30 years. ⁴ Rectal metastasis revealing breast cancer has been described by others.^5,6 It may be a solitary metastasis or a part of generalized metastatic disease.

Lobular carcinoma is the predominant type prone to metastasize to the rectum, despite a much greater prevalence of ductal carcinomas among all breast cancer primaries.^4,6 These metastases must be differentiated from a GI primary tumor because the treatment is completely different, and misdiagnosis will result in inappropriate management. ⁷ The diagnosis of rectal metastasis from breast carcinoma is not easy because it is infrequent, and the lesion can mimic a primary rectal tumor. The symptoms are nonspecific, and usually attributed to the side effects of chemotherapy or to paraneoplastic syndromes. In such cases, sigmoidoscopy is useful; the macroscopic appearance includes thickening and rigidity of the rectal wall known as linitis plastica. Deep biopsies with IHC are the best modality for establishing the correct diagnosis. ¹ Pathologic criteria include infiltration of the serosal, muscular, and submucosal layers, with small cells with monomorphic, round nuclei and vacuolated cytoplasm, typically arrayed in chords, named "indian files"; this pattern of infiltration provokes an intense fibrous reaction, macroscopically evident as linitis plastica, which occurs both in the stomach and in the rectum. ⁶ Histopathologic comparison of mammary and GI specimens is mandatory. Metastatic breast carcinomas are usually positive for ER, PR, CK7, gross cystic disease fluid protein 15 (GCDFP-15) and negative for CK20.^8,9

The treatment of rectal metastasis is based on hormonal or chemotherapy, whereas palliative surgery is proposed mainly for patients with symptomatic stenosis, complete obstruction, or hemorrhagic complication. ⁵ The prognosis is still poor, with overall response to the different treatment modalities ∼53%, ¹⁰ and a median survival of ∼ 1 year. ⁴

Conclusion

Rectal metastasis of breast cancer may occur early or late in the course of breast cancer. This diagnosis should be suspected whenever a patient with a history of breast cancer experiences GI symptoms, even in the absence of breast metastasis in other common locations.