[A boy with cervical focal myositis].

[focal myositis]

Focal myositis is a rare idiopathic pseudotumour that mostly occurs in the extremities in adults .An 8 -year -old boy presented with a few months history of swelling in the neck and fever . Ultrasound investigation revealed an inhomogenous mass consistent with lymphadenitis . After nine days of antibiotic therapy , the clinical picture of fever and swelling was unchanged . MRI imaging revealed continuity of the swelling in the sternocleidomastoid muscle and a malignant process was suspected . Microscopy showed no malignant cells , however , but a lymphoplasmocytic infiltration with fibrosis and degeneration of muscle fibres , consistent with focal myositis . No intervention was undertaken and one year after presentation the tumour had regressed almost entirely .Focal myositis can present as a cervical tumour . On ultrasound , the condition is hard to distinguish from lymphadenopathy or malignancy . In cases of insufficient response to empirical antibiotic therapy , focal myositis should be considered .