Glomus tumours of the knee: a case series

To review clinical and magnetic resonance imaging (MRI) features of patients with glomus tumour of the knee, and compare the present findings with cases from the English literature.

The orthopaedic oncology and pathology databases at The University of Chicago were reviewed for cases of glomus tumour and small subcutaneous anterior knee masses. For all glomus tumours, the site of the tumour and age and sex of the patient were recorded. For those tumours arising in the knee, the symptom profile and MRI characteristics were recorded. The English literature was reviewed for cases describing glomus tumours in the knee.

Thirty-four patients with glomus tumour were recorded. Five glomus tumours occurred in the anterior knee, all in men aged ≥30 years, four of whom had a several-year history of pain prior to diagnosis. MRI showed small (<2 cm) nodular enhancing masses. Review of the English literature supports the anterior knee as a common location for lower-extremity glomus tumours, with a male predominance and several years of pain preceding diagnosis.

Although rare, glomus tumours occur in the knee. Unlike the classic description of glomus tumours occurring in the fingers most typically in women <30 years of age, those that occur in the knee tend to do so in men >30 years, and many years of pain can precede diagnosis. The astute radiologist may be the first to suggest this diagnosis if a small, painful, enhancing, nodular subcutaneous mass is noted on knee MRI examinations.