[Interstitial granulomatous dermatitis and paraneoplastic rheumatoid polyarthritis disclosing cancer of the lung].

INTRODUCTION

Interstitial granulomatous dermatitis is a histological entity usually associated with systemic auto-immune conditions or malignant lymphoproliferation. Its spontaneous regression after surgical treatment of a lung cancer suggests an eventual paraneoplasic variant.

OBSERVATION

A 62 year old male patient, a smoker, was hospitalized for weakness, pruritus and symmetrical arthritis of small and large joints. Numerous rheumatoid nodules were located on the extensor aspects of the involved joints. During hospitalization, he developed an inflammatory plaque located on a thigh, which showed histologic features consistent with the diagnosis of interstitial granulomatous dermatitis. He had elevated E.S.R., blood eosiniphilia, and the search for antinuclear antibodies and antineutrophilic leukocyte cytoplasm antibodies (ANCA), of the p-ANCA type, was positive. A lung C.T. scan showed a cavitary tumor. Surgical removal of this tumor evidenced a bronchial squamous cell carcinoma. Four week after surgery, clinical signs and eosinophilia disappeared. After 6 months, ANCA became undetectable.

DISCUSSION

Parallelism between the evolution of the cutaneous and articular symptomatology and of the cancer are diagnosis of paraneoplastic rheumatoid arthritis and paraneoplastic interstitial granulomatous dermatitis. Paraneoplastic rheumatoid arthritis is very unusual and this is the first reported case of simultaneously occurring paraneoplastic interstitial granulomatous dermatitis.