Ganglion cyst of Hoffa's fat pad of knee-a rare cause of knee pain and swelling-a case report and literature review.

Ganglion cysts around knee joint are uncommon and that from Hoffa's fat pad are even rarer. We present a case of 30 year old male patient with complaint of pain and swelling in left knee joint. Radiograph did not show any bony abnormality. MRI showed large tubulocystic lesion within Hoffa's fat pad which showed low signal intensity on T1-weighted images and high signal intensity on T2-STIR images. Open excision of the lesion was done. Histopathology of the specimen confirmed the diagnosis of the ganglion cyst. In follow-up, patient had asymptomatic left knee with full range of motion and did not show any sign of recurrence. Ganglion cysts from fat pad though very rare but should be considered in differential diagnosis to have an early diagnosis and management. Symptomatic ganglion cyst should be excised by open procedure or arthroscopically depending upon the size and extent of the lesion.