Acute Upper Extremity Edema in a 10-Year-Old Girl as Presenting Symptom of a Rare Cancer.

Acute onset upper extremity edema can pose a diagnostic challenge for the emergency physician, with conditions ranging from mild local allergic reactions to deep venous thrombosis to underlying life threatening conditions. We discuss a case of a 10-year-old female with upper extremity edema and the diagnostic considerations, which ultimately led to uncovering a malignant etiology. This case represents a rare presentation of her underlying diagnosis, anaplastic large cell lymphoma.