Squamous cell carcinoma of the lung associated with anti-Jo1 antisynthetase syndrome: a case report and review of the literature.

Antisynthetase syndrome is a heterogeneous idiopathic inflammatory myopathy. Anti-Jo1 is the most common antibody found in this condition. Dermatomyositis is known to be associated with malignancy, but the association between antisynthetase syndrome and malignancy is not clearly established. We report a case of an association of squamous cell carcinoma of the lung and anti-Jo1 antisynthetase syndrome. A 67-year-old man presented with polyarthritis, muscle weakness of the pelvic girdle, "mechanic's hands," and weight loss. A diagnosis of antisynthetase syndrome was considered based on the clinical features and the presence of anti-Jo1 antibodies. Positron emission tomography was performed because of weight loss and revealed a pulmonary hypermetabolic lesion. Histological findings revealed squamous cell carcinoma. The patient underwent lobectomy and is currently free of symptoms with regular monitoring. This unusual presentation of squamous cell carcinoma of the lung illustrates the need of a systematic approach to the diagnosis of antisynthetase syndrome. Positron emission tomography can be a useful imaging modality in the diagnosis of paraneoplastic syndromes associated with antisynthetase syndrome especially in the presence of warning signs/symptoms.