Mass Compression from Recurrent Lymphoma Mimicking Lower Extremity Cellulitis.

Cellulitis is a common skin and soft tissue infection with substantial misdiagnosis rates due to its nonspecific clinical characteristics. In this report, we present a patient with recurrent metastatic diffuse large B-cell lymphoma (DLBCL) masquerading as a unilateral lower extremity cellulitis. A 62-year-old man with a history of DLBCL, in remission for two years, presented with a two-week history of swelling and erythema of the right thigh and leg. Despite treatment with clindamycin and cephalexin, the redness and swelling continued to progress. On presentation to the emergency department, vitals were within normal limits, laboratory workup was significant only for borderline anemia and thrombocytopenia, and bilateral lower extremity ultrasound was negative for a clot. The patient was evaluated by a dermatologist who recommended further imaging workup for proximal vascular compression given the uniformity of inflammation and edema in the absence of fever or systemic symptoms. Imaging revealed retroperitoneal lymphadenopathy, right pelvic side wall and right inguinal lymphadenopathy, an intramuscular lymphomatous involvement of the right iliopsoas muscle, and mass compression of the right external iliac vein. Bone marrow and soft-tissue biopsies confirmed recurrent and metastatic DLBCL. In this patient, the atypical cellulitis-like features are likely due to venous and lymphatic obstruction secondary to mass effect from metastasis. Going forward, clinicians should consider compression-induced edema as a sign of primary or recurrent malignancy in patients with refractory or atypical cellulitis.