Unusual Pattern of Invasive Lobular Carcinoma Metastasis: A Case Report.

BACKGROUND Metastasis of breast cancer to the gastrointestinal (GI) tract is not common, however, invasive lobular carcinoma is more likely to metastasize to the GI tract than ductal carcinoma. The simultaneous metastasis of invasive lobular carcinoma to the GI tract and ovaries is an extremely uncommon presentation, which may mimic another rare entity that is peritoneal carcinomatosis secondary to breast cancer. Diagnosis of this entity is difficult as it can masquerade as a primary disease process instead of a secondary one. Treatment is even more difficult due to the sparsity of guidelines regarding this presentation. CASE REPORT A 58-year-old female with a history of invasive lobular carcinoma of the left breast treated 5 years prior to presentation with GI symptoms. Workup revealed a stenosis of the sigmoid colon; however, colonoscopy and biopsy did not show signs of malignancy. The patient was initially diagnosed with diverticulitis and given appropriate treatment which mildly improved her symptoms but did not eradicate them. Continued symptoms and failed attempts at diagnosis prompted the decision to perform an exploratory laparotomy which revealed metastasis of invasive lobular carcinoma to the sigmoid colon, appendix, and ovaries. CONCLUSIONS GI metastasis of breast cancer is a difficult entity to diagnose and treat. Concomitant metastasis to the GI tract and genitourinary system is even more challenging to diagnose and treat. These variable metastasis presentations of breast cancer indicate a need for more specific modalities for follow-up of breast cancer patients especially those with the invasive lobular subtype which tends to metastasize to unusual distant sites and present years after diagnosis and treatment of the primary disease.