Glomus tumour of the fourth toe: case discussion and review of literature

Abstract

This is a case report with literature review and discussion of current diagnostic studies and management of a rare case of glomus tumour in the fourth toe of a 36-year-old male patient.

Background

Glomus tumours are rare and mostly benign neoplasms arising from normal glomus bodies, which are contractile neuromyoarterial structures responsible for adjusting blood pressure and temperature within the cutis by controlling peripheral blood flow.^{1 2} Glomus bodies are composed of an afferent arteriole, a Suquet-Hoyer canal, an efferent venule and actin-containing glomus cells surrounding the canal.³

As previously mentioned, this tumour is rare and constitutes 1%–5% of all hand tumours⁴ and less than 2% of soft tissue tumours.⁵ It seems to have an anatomical predilection to fingertips especially in the subungual zone, most probably due to the dense concentration of glomus bodies in this region. Extradigital locations have been reported with lesser frequency, such as the head, neck, stomach, lung, tongue, colon, bladder and coccyx.^{4 6–8}

After a thorough review of the literature, we noticed the paucity of articles reporting this tumour in the toes and even the low frequency of its growth in the lesser toes. To the best of our knowledge, the farthest this lesion has been described was in the third toe^{9 10}; thus, we felt that it could be useful to share this case report of a glomus tumour in the fourth toe.

Case presentation

The patient is known to be a power lifter and has lately reported a change in his shoe wear to a tighter fit sports shoe, which in his opinion would have been the origin of his ailments. He has been seen first by his family physician, who advised him to wear a wider fit shoe box and stopped him from power lifting for a month, assuming that the lesion was a subungeal haematoma resulting from repetitive trauma while exercising.

We herein report the case of a 36-year-old male patient who presented to our clinic for pain in his left fourth toe that started 3 months ago. He had noticed as well the appearance of a small subungeal zone of bluish hue discolouration at the proximal lateral angle of his nail. His pain was triggered by very small trauma on shoe wear and exacerbated by cold temperatures.

Looking at the fact that his pain has not resolved, he took the second opinion of a general surgeon, who suggested it was an ingrown nail and proposed surgery, which he did not proceed with. He took the third opinion of a neurosurgeon, who suggested it was a neuroma and proposed rest and cortisone injection, which he also refused.

He finally came to us for a fourth opinion. On clinical exam, there was a subungual zone of bluish hue discolouration on the left fourth toe (figure 1). We were able to elicit paroxystic pain on touch with a pinhead (positive Love test) and with ice exposure, which were completely abolished with tourniquet inflation (positive Hildreth test).

Figure 1.

Image of the fourth toe with the black arrow pointing to the subungeal blue hue lesion.

Investigations

X-rays of the foot and the fourth toe did not show any signs of bony anomaly (figure 2), so we proceeded with MRI, which showed a well-circumscribed focal mass of 5.6×2.5×4mm in size, with hyperintense signal on T2-weighted and low-intensity T1-weighted images of the nail-bed of the fourth digit (figure 3A–C). Additional T2 Short Tau Inversion Recovery Sequence (STIR) diffusion weighted and T1 fat saturation axial sequences were obtained following contrast administration. The latter showed a well-circumscribed lesion with minimal enhancement without any cortical phalangeal bone involvement, suggesting a differential diagnosis of a glomus tumour or of an organised haematoma (figure 4).

Figure 2.

X-rays of the left foot.

Figure 3.

MRI of the left foot in (A) coronal view T1 sequence, (B) coronal proton density (PD) fat saturation (FS) sequence and (C) sagittal T2 FS sequence.

Figure 4.

MRI of the left foot in coronal T1 postcontrast sequence.

Treatment

We proceeded with excisional biopsy under local digital nerve block, using a dorsal approach through the nail matrix after removing the nail plate (figure 5A,B). We were able, under microscope enhancement, to successfully remove the entire lesion, which was well encapsulated with well-defined margins along normal soft tissue. Pathological examination (figure 6) came back positive for glomus tumour with negative margins.

Figure 5.

Intraoperative image showing (A) the tumour underneath the nail-bed through our median incision and (B) surgical bed following tumour resection.

Figure 6.

Pathology of the resected lesion.

Outcome and follow-up

The patient was seen 2 months following surgery. His pain has totally resolved, enabling him to return to his previous physical activities. The fourth toenail was progressively growing back.

Discussion

Glomus tumours are rare benign neoplasm first reported by Wood in 1812 as ‘painful subcutaneous tubercles’.¹¹ It was first described in 1924 by Barré and Masson and was named after them, the Barré-Masson syndrome.¹² It arises mainly in the fingers, with a female predominance and an age predilection to the fourth decade.^{9 13 14}

The presented case is rare in terms of its location in the fourth toe of a male patient in his 30s, decreasing the level of suspicion and hence delaying time to reach a proper diagnosis. Just as it has been noticed in all large case series,^{9 13 15} our patient has already took multiple opinions from several medical specialties before reaching us with full clinical evidence of a glomus tumour. We believe that sharing our current finding will help raise level of awareness on this rare lesion among clinicians making imaging requests, and make referrals and surgeries more targeted, which in return will decrease patients’ frustration and suffering and overall healthcare cost, looking at the fact that these lesions are usually mistaken for and treated as ingrown nails, neuromas, exostoses or osteoid osteomas, among others.

The classic triad of symptoms, namely pain, point tenderness and cold hypersensitivity, was present. Love and Hildreth tests were also positive. As discussed by Bhaskaranand and Navadgi¹⁶ in their experiment on 18 patients, the cold sensitivity test had the highest specificity, sensitivity and accuracy at around 100%, followed by Love test, which was 100% sensitive and 78% accurate, and Hildreth test, which was 71.4% sensitive, 100% specific and 78% accurate. Combining all three tests was recommended to increase diagnostic accuracy and yield, which has been done in our case.

From a radiological point of view, X-rays may occasionally show some phalangeal bony erosions but might not be helpful in narrowing the differential diagnostic, and such was the case with our patient, where radiographs were completely normal.

Colour duplex ultrasound on the other hand can detect lesions as small as 2 mm with a specificity of around 67% according to the case series of Marchadier et al ¹⁷ and 100% detection rate with no false-negatives in the case series conducted by Chen et al.¹⁸ It has the advantage of being low cost and readily available. It typically shows a hypoechoic mass with hypervascular appearance on power Doppler.

MRI can also detect lesions as small as 2 mm, showing low T1-weighted signal and hyperintense T2-weighted images with enhancement on T1 after gadolinium injection sequence. Al-Qattan et al ¹⁵ found in their case series a sensitivity of 90%, a positive predictive value of 97%, a negative predictive value of 20% and a specificity of only 50%, making this imaging study at the same level or even fall behind sonography in terms of cost-efficacy and practicality. At our centre, MRI is easily accessible, so we went ahead with it.

Histologically, glomus tumours may arise from one or more components that form the normal glomus body as previously mentioned: glomus cells, vasculature or smooth muscles. Thus they are mainly subcategorised into three types. The first type is solid tumours, the most frequent variant representing 75% of cases and containing small amounts of smooth muscles and poor vasculature surrounded by glomus cells set in hyalinised or myxoid stroma.^{1 19} The second type is glomangioma, containing mostly vascular components and representing 20% of cases.¹⁹ The third type is glomangiomyoma, composed of vascular structures and mainly smooth muscles and representing 5% of all cases.¹⁹ Our case could be classified within the solid tumour subtype.

Malignant glomus tumour represents 1% of all glomus tumour cases^{1 19 20} and may probably arise from an exceptional rare dedifferentiation of benign glomus tumour.²¹ Folpe et al,²² in their study of 52 cases in 2001, tried to list histopathological criteria for malignancy: size superior to 2 cm, deep location, moderate to high nuclear grade, increased mitotic rate (>5 per 50 high power field) or presence of atypical mitotic figures. In case these criteria are met, the risk of metastasis is as high as 25%.^{19 22} None of the above features was seen in our case; thus, it was classified as benign.

Concerning our surgical technique, we adopted the approach through the nail matrix after nail plate removal, which gave us maximum exposure and would decrease risk of recurrence.²³ Other approaches have been described in the literature, such as lateral paraungual below the matrix,²³ which is more attractive due to the lower risk of nail matrix regeneration and aesthetic problems, but has higher recurrence rates due to its lower exposure and risk of incomplete tumour removal. According to Lin et al ²³ in their analysis of 75 cases, the two major factors for recurrence are operative approach and skin-coloured tumours, which might lead to incomplete resection. In our case, the mass had a brown-bluish colour well distinct from the rest of the normal soft tissues, which in addition to use of microscope helped us achieve complete resection.

In conclusion, glomus tumours are rare benign neoplasms requiring surgical removal in most cases. They present a clear diagnostic challenge due to their rare occurrence in our practice; thus, clinicians should maintain a high level of suspicion and awareness in order to decrease patients’ suffering and healthcare cost.

Learning points.

• A high level of awareness and suspicion should be maintained in order to diagnose this lesion as early as possible.

• All three clinical tests (triad of symptoms, Love and Hildreth tests) should be combined to increase diagnostic accuracy and yield.

• Ultrasound and MRI are good imaging studies, although the first might be more readily available and cost-effective.

• Trans-nail matrix approach and use of microscope during surgery might help decrease recurrence rate.