An unusual cause of massive rectal bleeding.

Area of Science:

• Gastroenterology
• Oncology
• Hematology

Background:

• A 76-year-old female patient with a history of multiple myeloma, treated with Lenalidomide-Dexamethasone since 2018, presented with significant rectal bleeding.
• Previous medical history included angiodysplastic lesions in the right colon treated with argon plasma coagulation (APC) and a normal colonoscopy in 2019 for chronic diarrhea.

Observation:

• The patient presented with massive rectal bleeding, leading to a hemoglobin decrease to 9 g/dL.
• Colonoscopy revealed significant edema of the cecal-ascending colon and rectosigmoidal mucosa.
• Additional findings included important submucosal hematomas and bleeding mucosal tears, with mild erythema in the remaining colon mucosa.

Findings:

• The observed colonic mucosal edema, submucosal hematomas, and bleeding tears in a patient with multiple myeloma on Lenalidomide-Dexamethasone treatment are indicative of a potential drug-induced gastrointestinal toxicity or a severe complication.
• Differential diagnoses should consider medication side effects, particularly related to Lenalidomide, and other causes of lower gastrointestinal bleeding in immunocompromised patients.

Implications:

• This case highlights the critical need to consider medication side effects, especially Lenalidomide-induced gastrointestinal complications, in patients with multiple myeloma presenting with severe rectal bleeding.
• Prompt diagnosis and management are essential to prevent further complications and improve patient outcomes in this vulnerable population.