Department of Rheumatology, Royal Free Hospital, Pond Street, London and 1Department of Respiratory Medicine, Watford General Hospital, Vicarage Road, Watford, UK
Correspondence to: J. Watkins, Department of Rheumatology, Royal Free Hospital, Pond Street, London NW3 2QG, UK. E-mail: drjennywatkins{at}yahoo.co.uk
SIR, The most common myositis-specific antibody is anti-Jo1, a precipitant antibody against the intracellular enzyme histidyl tRNA synthetase. This is one of the five antibodies associated with polymyositis in the antisynthetase group [1]. This group of antibodies presents with characteristic clinical features known as the anti-synthetase syndrome, which includes myositis, interstitial lung disease, arthritis and Raynaud's phenomenon [2, 3]. Polymyositis and dermatomyositis have an association with malignancy. A large population-based study in Sweden found increased malignancy in 15% of 392 patients with dermatomyositis and 9% of 396 patients with polymyositis [4]. There has been only one report in the literature in which the presence of the Jo-1 antibody is associated with occult malignancy [5]. Here we report the case of a patient with the anti-Jo1 antibody syndrome in association with poorly differentiated adenocarcinoma.
A 58-yr-old male smoker with no significant past medical history presented to the out-patients department with a 10-month history of persistent dry cough and progressive breathlessness. Examination revealed toe and finger clubbing and fine bibasal crepitations in the chest. He was positive for antinuclear antibody nucleolar pattern and for anti-Jo1. Chest X-ray demonstrated fine bibasal reticular shadowing.
Two weeks later the patient presented with increasing breathlessness, painful finger lesions and Raynaud's phenomenon. He had constitutional symptoms with fevers, sweats, malaise and myalgia. Multiple splinter haemorrhages and one Osler's node were noted. He was apyrexial and tachycardic, and had a blood pressure of 98/56 and a respiratory rate of 30. Heart sounds were normal with no murmurs, and chest examination remained unchanged. He had reduced power in the proximal muscles of his upper and lower limbs (4/5, where 5 = normal power and 0 = no power). Urine dipstick was negative. Laboratory tests showed elevated white blood cell count at 18.43^x^109/l (neutrophilia), platelets 438^x^109/l and haemoglobin 10.2 g/dl. Urea and creatinine were normal. The C-reactive protein (CRP) concentration was 33 mg/l and erythrocyte sedimentation rate (ESR) 34 mm/h. Creatinine kinase was elevated at 235 U/l. An urgent transthoracic echocardiogram was normal and three sets of blood cultures were subsequently negative.
In view of his rapid clinical deterioration, he was treated with three pulses of 1 g methylprednisolone and broad-spectrum antibiotic cover. An initial dramatic improvement was noted in the patient's clinical condition over the next 24 h, mirrored by a reduction in the CRP and ESR.
Within 48 h he developed a swollen, tender right leg. Vascular study showed an extensive deep-vein thrombosis. He was given anticoagulation treatment.
On further investigation, formal pulmonary function tests demonstrated a forced expiratory volume in 1 s (FEV1) of 35%, forced vital capacity (FVC) 49%, FEV1/FVC 78%, carbon monoxide transfer factor (TLCO) 39.4% and transfer coefficient for carbon monoxide (KCO) 61.4%. Computed tomography (CT) of the chest showed established pulmonary fibrosis and enlarged lymph nodes in the mediastinum (Fig. 1). Subsequent abdominal and pelvic CT scanning demonstrated extensive para-aortic and coeliac axis lymphadenopathy. There was almost total obstruction of the inferior vena cava with clot extending close to the hepatic veins, and a filling defect in the superior vena cava suggestive of thrombus. CTpulmonary angiography showed multiple pulmonary emboli. Lymph node biopsy showed a poorly differentiated adenocarcinoma. An EMG study was performed following steroid treatment and showed no significant abnormality. Thrombophilia screening, including anti-cardiolipin antibody, lupus anticoagulant and B2-glycoprotein 1, was negative. The tumour markers CEA, CA 153, CA 199 and CA 125 were all elevated. The primary site of the adenocarcinoma remains unknown.
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In summary, polymyositis/dermatomyositis is associated with interstitial lung disease or malignant neoplasms, though rarely in co-existence. There has only been one previous case of Jo-1 syndrome with associated malignancy reported in the literature. In 1992 Iwasaki et al. [5] reported the case of a patient with polymyositis, interstitial pneumonitis and a positive Jo-1 antibody with a left renal clear cell carcinoma. Our patient presented with the clinical features of polymyositis and pulmonary fibrosis with the presence of the Jo-1 antibody. Upon further investigation he was found to have disseminated, poorly differentiated adenocarcinoma complicated by a hypercoagulable state. It is accepted that this could be a chance association.
The authors have declared no conflicts of interest.
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