Secondary Hemophagocytic Lymphohistiocytosis as the Initial Presentation of Metastatic Carcinoma of Likely Colorectal Origin

Hemophagocytic lymphohistiocytosis (HLH) is a potentially fatal hyper-inflammatory syndrome, often secondary to an underlying trigger in adults. Among secondary causes, malignancy-associated HLH carries the poorest prognosis, though association with solid tumors is rare. We describe a patient with metastatic carcinoma of probable colorectal origin who initially presented with back pain and findings suggestive of infection involving the lower spine. He was later diagnosed with HLH, but owing to poor performance status, he was not eligible for chemotherapy and was managed with dexamethasone. He progressively declined, and died on day 54 of hospitalization. To date, this represents the third reported case of HLH as the presenting feature of colorectal cancer, and the second case in which diagnosis was established through immunophenotyping. The rapid course underscores the aggressive nature of malignancy-associated HLH and the importance of considering occult cancer when evaluation for secondary HLH does not reveal an obvious cause.