Glomus Tumors: A Clinical Study of 143 Patients

One hundred and forty-three patients with glomus tumors were diagnosed between 1991 and 2024. Glomus tumors (GTs) were painful to pressure in 81.1% of cases and to cold in 10.5%. Most lesions were non-subungual (103/143, 72%). In females, glomus tumors were usually located in the subungual region of the fingers, while in males, they were more common in non-digital regions of the extremities. Compared with GT developed in other sites, subungual GTs are more frequently painful to pressure and to cold, and they are often correctly diagnosed before histological confirmation. GTs are relatively common neoplasms that belong to the group of painful cutaneous tumors. GTs frequently occur in the subungual region, where they may be particularly bothersome to patients. Approximately 1% of GTs are considered malignant (glomangiosarcoma), and 40% may produce metastasis [1]. We retrospectively analyzed the clinical features of 143 GTs diagnosed between 1991 and 2024 (73 women and 70 men, mean age 54.36, standard deviation [SD] 16.646). Clinical features are summarized in Tables 1 and 2. In 116 patients, the lesions were painful to pressure (81.1%), and in 15 cases, they were also painful to cold (10.5%). Most lesions were non-subungual (103/143, 72%). Subungual lesions (40/103, 28%) were more frequent in the fingers (37/40, 92.5%) and in females (33/40, 82.5%). The proportion of erythematous lesions and lesions painful to cold was higher in the subungual location (p = 0.005 and p = 0.032, respectively). In four patients, the GTs were considered malignant (glomangiosarcoma) (2.8%), and their median diameter was greater than that of benign GT (19.5 mm, interquartile range [IQR] 24 vs. 5 mm, IQR 4, p = 0.022). Four patients had neurofibromatosis type 1 (2.8%). One patient presented with multiple lesions (two lesions, one on each leg). Treatment was surgical excision in most patients. Excision was complete in 95 of the 123 cases where this information was available. Only seven patients with benign GTs (5%) developed local recurrence, all of which had been incompletely excised. The earliest descriptions of GT considered the most frequent site to be the digits, particularly the subungual region [2]. However, in recent series, subungual GT represents only 33%–39% of cases [2, 3], 28% in the present study (40/143). In our patients, subungual GTs were much more common in the fingers than in the toes (37/3) and were mostly observed in women (33/40, 82.5%). This may suggest that some unknown sex-related factors may predispose patients to preferential GT development in different locations. Subungual GTs were more frequently painful than in other sites, and the presumptive clinical diagnosis of subungual lesions was correct in most cases (37/40, 92.5%). Possibly due to the limited space under the nail plate, our subungual GT showed a smaller median diameter at diagnosis compared to non-subungual tumors (4 vs. 5.5 mm, p < 0.001). Although initially GTs were not considered associated with any systemic disease, it has been estimated that 5% of patients with neurofibromatosis type 1 develop GT due to biallelic inactivation of the NF1 gene within the tumors [4]. In our series, four of 143 patients (2.8%) with GT had neurofibromatosis type 1, but none of them had multiple lesions. One of our 4 glomangiosarcomas developed local recurrence after complete excision, and another patient, regional metastases. Recently, BRAF V600E mutation has been identified in a proportion of malignant GTs, suggesting that BRAF inhibitors could represent a promising therapeutic option for metastatic cases [5]. Limitations of this study include its retrospective observational design, the fact that it was conducted at a single center, and the relatively small number of patients. In summary, although the typical clinical presentation is more frequent in subungual GT, most of the included tumors were located in non-subungual sites (72%). In women, GTs had a predilection for the subungual region of the fingers, whereas in men, they were more frequent in extradigital extremity sites and rarely involved the subungual region. Compared with GTs developed in other sites, subungual GTs were more often painful to pressure, more frequently cold-sensitive, had a smaller diameter at diagnosis, were more often erythematous, and were more likely to be clinically diagnosed before histological confirmation. The work is original and is not under review by any other journal. The signing authors meet the authorship requirements. The study protocol was reviewed by the Research Ethics Committee of Bellvitge University Hospital: reference PR 281/24. The authors declare no conflicts of interest. The data that support the findings of this study are available on request from the corresponding author.