Characteristics of glomus tumors in the hand not diagnosed on magnetic resonance imaging.

PURPOSE

To determine whether the diagnosis of hand glomus tumors by magnetic resonance imaging (MRI) is associated with tumor size, tumor pathology, tumor location, and/or clinical suspicion.

METHODS

We reviewed our pathology database for patients with hand glomus tumors diagnosed between 2006 and 2013 and included those patients who had preoperative MRI at our institution. We excluded patients with recurrent and persistent tumors. Magnetic resonance imaging reports were reviewed for clinical history, tumor location, and associated bone erosion. Pathology reports were reviewed for diagnosis and tumor size. We classified MRI studies as positive (glomus tumor diagnosis), negative (no mention of glomus tumor as possible diagnosis), or indeterminate (glomus tumor mentioned as possible differential diagnosis). Fisher exact test was used to compare positive studies and those that were nondiagnostic (ie, either negative or indeterminate).

RESULTS

Of the 46 patients who had pathologically confirmed hand glomus tumors, 38 had preoperative MRI studies. A total of 24 MRI studies were positive, 5 were indeterminate, and 7 were negative. Five patients had atypical pathology, 1 had a multifocal tumor, and 2 had extra-digital hand glomus tumors. Failure to diagnose glomus tumors on MRI was associated with atypical pathology, atypical location (ie, not located in the subungual region), absence of bone erosion, and lack of clinical suspicion. Tumor size was not associated with MRI diagnosis.

CONCLUSIONS

In this series of 36 hand glomus tumors, one-third of MRI studies were nondiagnostic. Occurrence of nondiagnostic MRIs was more likely when glomus tumors were pathologically and/or anatomically atypical, without bone erosion, and with no or unrelated clinical history provided. These findings highlight the continued importance of clinical suspicion in glomus tumor diagnosis.

TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic IV.