[Febrile cellulitis surrounding a scar revealing a large immunoblastic B-cell lymphoma].

BACKGROUND: Secondary skin sites of lymphoma appear in the advanced stages of the disease. We report the first case of a pericicatricial skin infiltration, mimicking febrile dermohypodermitis, revealing diffuse immunoblastic large B-cell non-Hodgkin's lymphoma. PATIENTS AND METHODS: Four months after decompressive cervical laminectomy, a 56-year-old man presented an inflammatory pericicatricial patch evoking cellulitis in a setting of hyperthermia and lymphadenopathy. Blood cultures and bacteriological analysis of skin biopsy samples were negative. The images showed infiltration of the soft subcutaneous areas and polyadenopathy. Two weeks later, several subcutaneous nodules appeared on the trunk. Histological analysis and immunolabelling pointed to immunoblastic large B-cell non-Hodgkin's lymphoma. A clone of B lymphocytes CD45+, CD20+, CD79a+, Bcl2+, CD5+, MUM1+, CD3-, CD10-, CD23- and Bcl6- was seen. The remainder of the extension examination was negative. CHOP-rituximab polychemotherapy resulted in complete regression of all lesions, notably the inflammatory cervical plaque. DISCUSSION: Secondary skin manifestations of lymphoma are generally non-specific (pruritus, ichthyosis, purpura, etc.) rather than specific in terms of lymphoid infiltration. As in our patient, certain cutaneous sites of lymphoma may have a misleading clinical presentation, histological analysis alone was able to provide a conclusive diagnosis. In our patient, the highly specific infiltration seen around the entire scar could either suggest a Koebner phenomenon or point to a role of the cutaneous aggression within the development of an inflammatory process contributing to pericicatricial infiltration by lymphoid cells. Locoregional invasion from the osseous part of the cervical spine and not macroscopically diagnosed during neurosurgery could also be responsible.