Rectal linitis plastica as the sole manifestation of breast cancer recurrence.

We present the case of a 51-year-old woman with a history of invasive lobular breast adenocarcinoma in remission for six years following surgery, chemoradiotherapy, and hormone therapy. During follow-up, an asymptomatic elevation of CA 15-3 was detected. A CT scan revealed rectal wall thickening suggestive of neoplasia, with no other lesions observed. Colonoscopy demonstrated a congested, thickened, and infiltrative mucosa in the rectal ampulla extending from the internal anal margin, accompanied by an impassable stricture 8 cm from the anal margin. Initial endoscopic biopsies were negative for malignancy. Endoscopic ultrasound (EUS) revealed rectal wall thickening, loss of normal wall stratification, and a regular outer border, findings consistent with rectal linitis plastica. The stricture prevented further advancement of the echoendoscope, but fine-needle biopsies were performed. Histological analysis confirmed adenocarcinoma infiltration of breast origin.