A rare case of extranasal NK/T cell lymphoma presenting as autoimmune rheumatic manifestations associated with Sjögren's syndrome

Dear Editor, A 75-year-old man visited the outpatient department in our hospital in November 2007 presenting with tender and swollen bilateral metacarpophalangeal joints and proximal interphalangeal joints with low fever. Serological tests revealed positive antinuclear antibody (ANA) of 1:320 (speckled), anti-SSA antibody (2+), positive rheumatoid factor of 53.60 IU/ml, and anti-CCP antibody of 21.54 RU/ml (positive, >5 RU/ml). He was given a presumptive diagnosis of early rheumatoid arthritis. Nine months later, the patient was admitted to the rheumatology department complaining of fever with myalgia. No tender and swollen peripheral joints were palpable. Physical examination for his lung, heart, and abdomen was unremarkable. He had normal muscle strength except dorsiflexion weakness in his left foot. Neurological examination did not show obvious abnormality. Routine laboratory results showed normochromic, normocytic anemia (Hb=79 g/L), mild proteinuria (0.6 g/day) without active urinary sediment. He did not complaint of gastrointestinal disorder and his stool was normal and negative for occult blood. An obviously elevated erythrocyte sedimentation rate at 130 mm/1 h (<20 mm/1 h) was noted, as well as Creactive protein at 95.90 mg/L (<8 mg/L). Mild ground-glass opacities at both lung bases were observed using high-resolution computed tomography. Although the patient had mild cough and his sputum culture was positive for Candida albicans, his fever did not respond to antibiotics therapy and his temperature ranged from 38°C to 39°C. Bone marrow aspirate and biopsy sample did not show any malignancy. There was no evidence for solid tumor. However, repetitive serological tests did indicate some abnormalities, including hypergammaglobulinemia, positive for ANA (1:320) with a speckled pattern, and positive for both anti-SSA antibody (2+) and RF (44.90 IU/ml). Specific autoantibody for SS-B was negative. Although the patient did not have dry eye and dry mouth, he had the objective evidence of dry eye, including Schirmer's test and staining test of the cornea with Rose Bengal which were both positive for bilateral eyes. And his salivary scintigraphy showed significantly delayed excretion of tracer. The salivary gland biopsy also exhibited the characteristic immunohistopathological alterations with a focus score ≥1. As for dorsiflexion weakness in his left foot, electromyography showed peripheral neuropathy with a normal level of creatine kinase. In brief, the patient had the following clinical features involving multisystems such as transient arthritis, fever with myalgia, mild proteinuria, mild interstitial lung disease, and peripheral neuropathy. Combined with his abnormal immunologic results and the objective evidence of his eye and salivary gland involvement, the present case apparently met the criteria for the diagnosis of Sjogren's syndrome. He was treated with prednisone (30 mg/day) and azathioprine (50 mg/day). When he was discharged, his fever resolved, and he was good in general condition. Unfortunately, the patient was readmitted to our hospital 2 weeks later, complaining of hemafecia. A full blood count showed a panhematocytopenia (white blood cell count 1.06×10/L, hemoglobin 37 g/L, platelet count 92×10/L). B. Yan (*) :Y. Liu :D. Hu Department of Rheumatology, West China Hospital of Sichuan University, No. 37, Guoxue Alley, Chengdu, Sichuan Province 610041, China e-mail: yb420@163.com