GLOMUS TUMOR – DERMOSCOPY AND SURGERY

Background. Glomus tumors are rare and mostly benign lesions of the subcutaneous tissue. Single lesions are preferably located on the acral parts of the body, including the subungual nail apparatus. Observations. We analyzed our files for glomus tumors of the last 10 years and found four tumors, with an equal gender distribution. The patients’ age ranged from 41 to 78 years. The dominant site was subungual on fingers. Advanced and long-standing tumors tend to destroy the overlying nail plate. Another tumor was found on the plantar heel. All patients had a delayed diagnosis between 3⁄4 of a year to three years. Nail plate dermoscopy is a useful tool for diagnosis of early subungual lesions. All tumors were successfully treated surgically with rapid and complete pain relief. Histologically, all four tumors were of the glomangioma subtype with predominant vascular structure. No relapse occurred within a follow-up of up to nine years. Conclusions. Glomus tumors are rare. In case of subungual localization, nail plate dermoscopy is a useful non-invasive diagnostic tool. The treatment of choice is complete tumor removal by surgery. A better knowledge of this tumor will help to reduce the time to final diagnosis and treatment. Cite this article: Uwe Wollina, Jacqueline Schönlebe. Glomus tumor – dermoscopy and surgery. RoJCED 2018;5(2):64-xx. Open Access Article https://doi.org/10.26574/rojced.2018.5.2.64


Introduction
Glomus tumors are rare mostly benign lesions occurring typically on the acral body parts but may occur in various localizations and organs (1).They can develop subungual in the lateral or central nail bed of fingers and toes.Here, the typical symptoms are subungual circumscribed purple erythema, paroxysmal pain and hypersensitivity to cold and pressure.Clinical diagnosis is possible by Love's pin test (severe pain when the nail plate above the lesion is pressed with a pin head), Hildreth's test (disappearance of pain and tenderness after application of a tourniquet cuff proximally on the same arm), and cold test (increased pain intensity with temperature drop).In typical cases, magnetic resonance imaging and ultrasound are not necessary for diagnosis and treatment planning (2).

Case series
We present a series of four patients with benign solitary glomus tumors of different localization (two females and two males).Their age ranged from 41 to 78.The symptoms were present for ¾ of a year to three years.The patients had consulted between two and four medical doctors before the final diagnosis, and treatment could be realized.The diagnosis was confirmed in all cases by histology and immunohistology.All patients underwent surgery and remained relapse-free.We observed no malignant glomus tumor.

Uwe Wollina, Jacqueline Schönlebe
Cases 1-3 -subungual lesions A 41-year-old male patient presented with a painful subungual lesion on his 3 rd left finger for about 12 months.He did not remember any recent trauma.Medical history was unremarkable.
On examination, a single erythematous subungual lesion of about 2 mm diameter was noted (Figure 1).For dermoscopy we used a DermLite 3 Gen Cam (DermLite; San Juan Capistrano; USA).On dermoscopy with polarized light, the lesion was clearly visible within the distal nail bed, with discrete ramified telangiectasias (Figure 2).Love's pin test and cold test were positive.The suspected diagnosis was a glomus tumor.The tumor was surgically removed by transungual approach with block anesthesia under tourniquet control.The nail plate was sutured above the resulting defect as a biologic protective dressing.The patient was painless after surgery.No relapse occurred.
Histologic examination showed a tumor with dilated vascular channels with lining CD34-and smooth-muscle actin-positive glomus cells, which confirmed the diagnosis of a subungual solitary glomangioma (Figure 3 a and b).
When subungual tumors enlarge, the nail plate becomes spliced as seen in a 58-year-old female patient and a 78-year-old male patient.In those cases, a similar surgical approach was used, and the patients became pain-free.No relapse occurred in the follow-up period of nine years (Figure 4 a and b).

Case 4 -a lesion on the plantar heel
A 59-year-old female with a history of cutaneous melanoma presented with a painful subcutaneous nodule on her right heel.Clinically, the lesion was palpable but not visible.
We performed minor surgery to remove the painful lesion (Figure 5

Discussion
Glomus tumors are rare.They represent less than 2% of benign soft tissue tumors.These tumors are composed of glomus cells, blood vessels, and smooth muscles.Benign glomus tumors can be differentiated into three subtypes, i.e. glomangiomas (vessels are predominant), solid glomus tumors (glomus cells are dominant), and glomangiomyomas (with a predominance of smooth muscles).Although the majority of glomus tumors of skin are benign, only 1% of all glomus tumors are malignant (3).Deep-seated tumors bear a higher potential risk of malignant transformation and metastatic spread.Five-year cumulative metastatic risk increased significantly for tumors with a size of more than 2 cm and with atypical mitotic figures (4).
Glomus tumors can occur as single or multiple lesions.Single lesions are more commonly seen in adolescents and adults and represent 90% of all   (5).However, the pain sensations are stronger in solitary lesions.Glomus tumors belong to the painful skin tumors under the mnemonic "Blue ANGEL" or "BENGAL": Blue rubber bleb nevus, Angiolipoma/Angioleiomyoma/Angiosarcoma, Neuroma/Neurilemmoma, Glomus tumor, Eccrine spiradenoma, and Leiomyoma.Due to the common symptomatology, these tumors need to be considered in the differential diagnosis of a glomus tumor.For the subungual lesions the following entities should also be evaluated: exostosis (6, 7), digital mucoid pseudocyst (8), and acquired digital arterio-venous malformation (ADAVM) (9).
The diagnosis of glomus tumor is primarily clinical for cutaneous and subungual lesions (Table 1) (10,11).Unfortunately, diagnosis is often delayed even after consultation with multiple medical disciplines (12).
For subungual tumors, this can lead to secondary nail plate destruction as seen in cases # 2 and #3.In other localizations chronic pain syndromes may develop (13,14).We observed chronic plantar heel pain as an uncommon presentation of a solitary glomus tumor in a 59-year-old female.
Nail plate dermoscopy is a non-invasive tool for diagnosis.The technique can reveal the presence of vascular structures: Sometimes these structures can be very discreet or even absent (discreet linear vascular structures or ramified telangiectasias) (15).We used nail plate dermoscopy for patient #1, where the lesions had not been long-standing.The nail plate was untouched.We identified ramified telangiectasias.
Surgery is the only effective method for glomus tumor treatment.For subungual lesions, both transungual and lateral subperiosteal (periungual) approach have been used successfully (16,17).Transungual surgery is the preferred method for tumors located medially, while perinugual surgery is preferred for lateral tumor position (18).

Conflicts of interest: none declared. Financial statement: none declared.
This work is licensed under a Creative Commons Attribution 4 .0Unported License.The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material.To view a copy of this license, visit http://creativecommons.org/licenses/by-nc/4.0/Uwe Wollina, Jacqueline Schönlebe a and b).On histology, the vascular tumor was positive for smooth-muscle actin and CD34 (Figure6a and b) and final diagnosis was glom angioma.After suturing the defect, wound healing was unremarkable.No relapse occurred during a five-year follow-up.

Figure 1 .
Figure 1.Clinical presentation of subungual glomus tumor in a 41-year-old male

Figure 5 .Figure 4 .
Figure 5. Glomus tumor of the heel in a 59-year-old female.(a) Excision of the subcutaneous lesion; (b) Surgical specimen

Table 1 .
Clinical tests for subungual and cutaneous glomus tumor glomus tumors, with a preference for acral body regions.Multiple glomus tumors are bluish deepseated nodules of childhood without acral dominance.They are also called glomuvenous malformations and are caused by mutations in the glomulin gene