[A pseudotumoral cutaneous form of sarcoidosis associated with non-Hodgkin lymphoma]

Sarcoidosis may be revealed by a variety of cutaneous signs, occasionally atypical. It may also be associated with a lymphoma. Herein we report an original case of pseudotumoral cutaneous sarcoidosis associated with malignant non-Hodgkin's lymphoma (MNHL).

A 64-year-old man was hospitalised for follicular and diffuse large B-cell MNHL localised in the cervical, subclavicular and inguinal lymph nodes. The skin examination revealed a bulky, erythematous, purple, infiltrated mass in the right lumbar region and two similar but smaller plaques in the dorsal region. The lesions were asymptomatic, present for six years, and stable. Histological examination of a skin biopsy sample revealed an epithelioid giant-cell granuloma without caseous necrosis. Bacteriological and mycobacteriological samples were sterile. Mediastinal adenopathies and pulmonary micronodules were found on CAT scan. A diagnosis of cutaneous and pulmonary sarcoidosis associated with the lymphoma was made. Polychemotherapy using CHOP combined with rituximab resulted in remission of the lymphoma but was ineffective against the sarcoidosis.

Pseudotumoral forms of sarcoidosis are rare and have a misleading clinical aspect. In our case, the cutaneous mass was evocative of a secondary lymphoma site. The diagnosis of sarcoidosis was based on clinical and laboratory findings and after elimination of other potential causes of granuloma. The appearance of a lymphoma in a patient with a history of sarcoidosis is rare but not fortuitous, since the notion of "sarcoidosis-lymphoma syndrome" exists. The incidence of lymphomas is 5.5-fold higher in patients presenting sarcoidosis than among the general population. Their time to onset is around 7 years after the discovery of sarcoidosis. The most common forms involve Hodgkin's disease. The efficacy of therapy on the blood disease underlying the sarcoidosis is variable.