Glomus Tumor as a Rare Cause of Anterior Knee Pain

Abstract

Anterior knee pain is caused by a variety of pathologies or anatomical abnormalities. Soft tissue tumors, although rare, can also be presented with anterior knee pain. A case of a glomus tumor located in front of the tibial tubercle, in a patient being treated for 2 years for chondromalacia of the patella is reported. A 28-year-old man presented to our hospital complaining of pain in the front of his right knee for approximately 2 years with gradually worsening over the recent 8 months. The patient has been treated for chondromalacia of the patella with non-steroidal anti-inflammatory drugs, physiotherapy and home exercises. A detailed physical examination of the knee revealed a painful soft tissue mass in the front of the tibial tubercle. Plain radiographs were normal. Ultrasonography of the right knee revealed an oval-shaped hyper/hypoechoic mass with multiple blood vessels in the surrounding area and clear margins. Magnetic resonance imaging (MRI) confirmed the presence of a small soft tissue mass with intermediate signal intensity similar to muscles on T1-weighted images and also intermediate signal intensity similar to surrounding fat on T2-weighted images. On T1 with fat saturation images the mass had high signal intensity (absence of fat). Finally there was an increased similar intensity of the mass after contrast medium administration (consisted of hypervascularity). The mass was excised, and the histology was characteristic of a glomus tumor. The patient was asymptomatic immediately after the operation. At the 2-year follow-up after the operation no recurrence was seen. J Med Cases. 2015;6(1):36-39 doi: http://dx.doi.org/10.14740/jmc2014w