Extreme hyperferritinemia without associated HLH in a patient with T-cell lymphoma.

Extreme hyperferritinemia has historically been associated with a short list of rare diagnoses, including hemophagocytic lymphohistiocytosis (HLH). However, hyperferritinemia is not specific for HLH in the adult population. Among other more common causes, T-cell lymphoma and other malignancies warrant evaluation prior to considering more rare diagnoses.