Glomus tumors around or in the knee: a case report and literature review

BACKGROUND

Glomus tumors commonly affect the extremities, especially subungual. And glomus tumors rarely occur around knee, which are often misdiagnosed. A lack of experience with glomus tumors is likely the cause.

CASE PRESENTATION

A 42-year-old female presented with continuous dull pain of right knee for the past 7 years. Severe pain was experienced after walking a few hundred meters or climbing up or down stairs. The patient had a slight limp, and the lateral superior aspect of her right knee was tender to palpation. The range of motion and skin around her right knee were normal. Magnetic resonance imaging revealed a well-defined abnormal lesion confluent with the periosteum on the femoral lateral supracondylar. She was finally diagnosed with glomus tumor according to pathological results. After surgery, the pain disappeared, and the patient was discharged three days postoperatively. At the 18-month follow-up visit, the patient reported sustained pain relief, and regular follow-ups were continued. Additionally, 30 published reports documenting 36 cases of glomus tumors around the knee were reviewed, which showed that 20% of all reported cases of glomus tumor around the knee had a history of trauma. The median age for male with glomus tumor was greater than that of female; however, the median duration of illness between the two groups was equivalent. The mean diameters of glomus tumors ranged from 4 to 65 mm, and locations around the knee included the knee joint cavity, soft tissue (e.g. popliteal fossa, patellar tendon, iliotibial band, and Hoffa's fat pad), distal femur, and proximal tibia.

CONCLUSION

Literature review demonstrated that no significant differences were found between male and female with glomus tumor in regard to location (left or right side) and illness duration. It was noting that a history of trauma may be a cause of glomus tumor and approximate 94.4% of glomus tumors was benign. The most effective therapy accepted for glomus tumors is complete surgical excision, and recurrence was rare after complete surgical excision.

Cutaneous malignant glomus tumours: applicability of currently established malignancy criteria for tumours occurring in the skin

Glomus tumours (GTs) have traditionally been classified into benign GTs, GTs with uncertain malignant potential and malignant GTs, based on a combination of criteria such as size of the tumour, degree of nuclear atypia and the level of mitotic activity. Several of the proposed grading criteria are difficult, or even impossible to apply for GTs occurring in the skin. The aim of the study was to analyse the applicability of the currently established GT malignancy criteria for tumours occurring in the skin and to establish their prognostic significance. A total of 25 benign cutaneous GTs, 11 new cutaneous malignant GTs and 36 cutaneous malignant GTs previously published in the literature were studied. We analysed the following clinicopathological features and correlated them with disease outcome: age, sex, site, size, depth of invasion, degree of nuclear atypia, mitotic activity, growth pattern, vascular invasion, spindle-cell morphology and tumoural necrosis. Of all the clinicopathological parameters analysed, only tumoural necrosis was found by univariate analysis (p = 0.001) to be associated with adverse biological behaviour, and none by multivariate analysis. Multivariate statistical analysis failed to detect any clinicopathological features predictive of the disease outcome (e.g., local recurrence, development of metastatic spread and/or death of disease) in cutaneous malignant GTs. Furthermore, the currently established malignancy criteria for cutaneous GTs can be difficult to apply, mainly due to their smaller size. Likewise, counting mitotic activity per 50 high power fields can often not be accomplished in GTs occurring at superficial locations. Complete excision of these tumours coupled with long-term follow-up is the mainstay of treatment for cutaneous malignant GTs. The results of our study also suggest that cutaneous malignant GTs follow a more indolent clinical course than their deep soft tissue counterparts.