Extradigital glomus tumour of the thigh causing 8 years of undiagnosed debilitating pain

Abstract

A woman in her mid-50s was referred to a plastic surgeon with an 8-year history of undiagnosed, localised severe, reproducible pain of the right thigh. Treatment with oral and topical analgesics, corticosteroids, acupuncture and physiotherapy did not provide symptom relief. She was referred to multiple specialists over the preceding 8 years including chronic pain physicians, physiatry, orthopaedic surgery and plastic surgery. Investigations including sonographic and MRI eventually revealed a non-specific soft tissue abnormality in the area of tenderness, which was excised en bloc. Histopathology revealed an extradigital glomus tumour. The patient’s symptoms immediately and permanently resolved postexcision.

Physicians seeing patients suffering from undiagnosed focal, reproducible pain should consider extradigital glomus tumours in their differential diagnosis. Workup for extradigital glomus tumour includes focused sonographic or MRI over the area of pain. Additionally, local injection of an anaesthetic agent can be used to assist with diagnosis.

Background

Accurate and detailed pain reporting was critical to correctly diagnosing the cause of our patient’s pain. This report describes the management of a woman with a rare pathology that caused her to live in excruciating pain for nearly a decade. Her pain was eventually cured through a simple surgical intervention.

Glomus tumours are vascular hamartomas that arise from neuromyoarterial cells, known as the glomus body, and account for less than 2% of all soft tissue tumours.¹ The classic presentation consists of severe focal paroxysmal pain and hypersensitivity to cold.² Glomus tumours are commonly thought to only be found in the subungual tissue of the distal phalanges. However, extradigital glomus tumours can arise anywhere in the skin and soft tissue, and are in fact more common than subungual glomus tumours.³ Given the perception that glomus tumours are confined to the digits, accurate diagnosis of an extradigital glomus tumour can be significantly delayed, leading to prolonged pain and suffering. Therefore, we argue that extradigital glomus tumours should be on a clinician’s differential diagnosis for patients who present with persistent and reproducible focal pain.

In this report, we describe a rare case of an extradigital glomus tumour of the thigh that went undiagnosed for 8 years, resulting in severe and debilitating pain affecting ambulation and activities of daily living. Several specialists were involved in this patient’s care prior to receiving the correct diagnosis. Here, we provide a summary of the literature on glomus tumours of the thigh (table 1), and outline recommendations for diagnostic testing and surgical intervention. This case also highlights the psychological impact of prolonged exposure to pain, and the importance of validating a patient’s pain experience.

Table 1.

Demographics of reported cases of glomus tumours in the thigh

Paper	Age/sex	Duration of symptoms prior to diagnosis	Differential diagnosis	Ultrasound findings	MRI findings	Tumour size	Area
Amillo et al8	38 F	18 years	Idiopathic myalgia	Well-defined, hypoechoic oval mass	Well-delineated nodule. T1-weighted images were hypointense ovoid tumour, which was enhanced by gadolinium injection. T2-weighed images were hyperintense.	3 cm in length	Right vastus lateralis
Beksaç et al9	39 M	2 years	Synovial sarcoma	N/a	N/a	1×1x1.2 cm	Left posterolateral thigh
Kloping et al10	56 M	6 years	Haemangioma	Partly cystic subcutaneous mass. Doppler showed blood flow in the cystic lesion.	N/a	15×10×5 mm yellowish-white thin encapsulated tumour	Posteromedial region of the left distal/left thigh
Lee et al11	66 F	8 years	None mentioned	Oval hypoechoic subcutaneous nodule. Colour Doppler showed subtle flow signals within the hypoechoic area.	Tiny soft tissue mass with intermediate signal intensity on T1-weighted images, hyperintensity on T2-weighted images and homogeneous enhancement after injection with gadolinium	5×5×2 mm	Right hamstring
López-Ríos et al12	56 M	6 months	None mentioned	N/a	N/a	0.8 cm in diameter	Right thigh
Luis et al13	74 M	2 months	None mentioned	N/a	N/a	1×1 cm	Right thigh
Sbai et al14	25 F	15 months	None mentioned	Fluid mass consistent with hydatid cyst of the soft tissue.	Rounded formation well-demarcated, with high signal intensity on T2 weighted images, low intensity on T1 weighted images.	3×2×2 cm	Left posterior (biceps femoris)
Sbai et al15	65 M	6 months	None mentioned	Echogenic, heterogenous, rounded soft tissue mass, well demarcated.	N/a	17 mm diameter	Right lower leg
So et al16	65 M	15 years	Complex regional pain syndrome and neuropathic pain	0.8×0.6 cm hypoechoic subcutaneous cyst	Non-specific	0.8×0.6 cm	Left anterior thigh
Sraj et al17	48		Glomus tumour, Schwannoma, traumatic neuroma, haemangioma, leiomyoma cutis, dermatofibrosarcoma protuberans	None	Subcutaneous lesion with intermediate intensity of T1-weighted images. T1-weighted image after gadolinium contrast injection showed the lesion enhanced. T2-weighted images showed a lesion of increased signal intensity.	1×1 cm	Medial region of the left knee/adductor canal

F, female; M, male; N/a, not available.

Case presentation

This is a case of a woman in her 50s who was referred to our plastic surgery clinic for persistent localised right anterolateral mid-shaft thigh pain that had gone undiagnosed for 8 years. The patient first presented to her family physician, and was diagnosed with right greater trochanteric pain syndrome (GTPS), formally known as trochanteric bursitis, despite no abnormal findings on MRI of the right trochanteric region. After 4 years of trialling various medical therapies directed at treating GTPS with no resolution of symptoms, the patient was referred for a bone scan of the right hip and femur, which also yielded no abnormalities. This prompted a referral to a physiatrist who again diagnosed the patient with right GTPS. It is important to note that at this point, the patient had seen several physicians and allied healthcare providers, all of whom diagnosed the patient with GTPS, despite consistent failure of standard therapy and no pathology seen on imaging. As the patient had already undergone a thorough trial of pharmaceutical optimisation and rehabilitation therapy for GTPS, the physiatrist recommended referral to a pain specialist for an ultrasound guided corticosteroid injection directly into the bursa. The injection was extremely painful for the patient, and provided her with no relief of her symptoms. A second corticosteroid injection was planned, this time at the site of pain (over the distal thigh); however, the procedure was aborted after the bedside ultrasound demonstrated a ‘non-compressible hypoechoic area between the muscle and fascia’ of the right anterolateral thigh. Due to the uncertainty of the diagnosis, the patient underwent an MRI scan (3.0 Tesla) of the right thigh, which showed ‘a focal nodular abnormality related to the deep fascia over the lateral aspect of the right thigh (measuring 1.1×1.1 cm), with associated soft tissue oedema’ (figure 1). The report noted that the appearance of the mass was non-specific, and radiology suggested a differential diagnosis of fat necrosis if there was a history of trauma, which there was not. The chronic pain specialists discharged the patient back to their primary care provider and recommended referral to an orthopaedic surgeon; no further local or regional blocks were attempted. After an initial consult with an orthopaedic surgeon, the patient was again discharged back to their family physician, and it was recommended that a referral be sent to a plastic surgeon specialising in nerve surgery (based on the history of neuropathic pain).

Figure 1.

MRI of the left thigh. (A) Axial view showing a focused area of hyperattenuation along the vastus lateralis, measuring 10.3×11.0×13.6 mm, with a high intensity T2 image with fat saturation (arrow). (B) Coronal view showing low signal intensity (arrow).

The patient was seen in our plastic surgery clinic, now 8 years after her initial onset of pain. Up to this point, she had tried several oral analgesics with minimal to no relief of her symptoms, including celecoxib (max dose 200 mg orally twice daily), gabapentin (max dose 300 mg orally three times daily), tramadol (dosing unknown) and naproxen (dosing unknown), as well as topical diclofenac (applied three times daily). Acupuncture, massage therapy, and physiotherapy also provided minimal benefit. At her initial visit, a detailed history was taken, which included administration of a self-reported pain questionnaire.⁴ The patient had no preceding trauma, and described a slow, progressive onset of focal discomfort. The pain was burning in nature with intermittent sharp pin-like sensations. There was no associated paresthesia, tingling, weakness, oedema, erythema, skin changes or radicular symptoms. The pain was constant—most severe in the morning, and aggravated by cold weather and movement (particularly knee flexion and prolonged ambulation). The pain made it difficult for her to ambulate and initiate sleep.

On a Visual Analogue Scale, the patient described severe pain (9/10) localised to the right thigh. The pain led to severe sadness (9/10), depression (8–9/10), anger (7–8/10), frustration (10/10) and stress (9–10/10). The pain symptoms affected her intimate personal relationships; however, she did not receive psychiatric or psychological treatments for the pain. Of note, her medical history was unremarkable.

On physical exam, there was a 2 cm area of focal tenderness over the distal anterolateral thigh, at the posterior border of the iliotibial band, which elicited reproducible pain on deep palpation. Sensation and strength testing was normal in the lower extremity.

Treatment

As the pain was focal and neuropathic in nature, but we could not definitively conclude that the symptoms were arising from the lesion, we injected 5 cc of 0.25% bupivacaine under ultrasound guidance to target the area. While this technique has been used to treat postsurgical neuromas,^{5 6} we are unaware of previous reports of using bupivacaine to diagnose the presence of a nerve tumour. At her follow-up 2 weeks later, the patient reported near-complete symptom relief for 10 hours following the local field block, after which her symptoms returned to baseline. After discussion of the risks, benefits and alternatives, the patient was consented for operative exploration of the area with possible neurectomy, and possible excision of lesion. The patient underwent surgical exploration of the area, including dissection down to the iliotibial band where a spongy, well-demarcated 2 cm vascular mass was identified. This was excised en bloc with a cuff of the surrounding iliotibial band. Subsequent pathology revealed the mass to be an extradigital glomus tumour (figure 2).

Figure 2.

Low (A) and high powered (B) views by routine histology shows a cellular tumour comprised of banal cuboidal cells condensing around admixed blood vessels consistent with glomus tumour. (C) The diagnosis is confirmed by immunohistochemical positivity of lesional cells for smooth muscle actin.

Outcome and follow-up

At her follow-up appointment 2 weeks postsurgery, she reported that the pain had completely resolved, and that she was ‘unbelievably happy.’ One year later, she remains symptom free, aside from some occasional scar tenderness at the surgical site.

Discussion

This case describes the clinical presentation of a woman in her mid 50s with an extradigital glomus tumour of the anterolateral thigh. While often considered to be rare, a study by Heys et al reported that extradigital glomus tumours account for 63% of all glomus tumours, with 14% of those being found in the leg.¹ Despite this, most patients with extradigital glomus tumours are commonly misdiagnosed, and suffer with pain symptoms for an average of 7 years prior to receiving curative surgical treatment.⁷ Of the extradigital glomus tumour cases found in the literature, all cases report a similar story—a patient with a long-standing history of undiagnosed focal pain (table 1).2 3 8–17 Oral and topical analgesics, as well as physical therapy, do not provide patients with adequate symptom relief. While histopathological findings provide the definitive diagnosis, medical imaging can be helpful in suggesting a diagnosis. Glomus tumours can be seen on ultrasound imaging as hypoechogenic, fluid-filled or cyst-like structures. If Doppler imaging is performed, it often demonstrates blood flow to the lesion.^{10 11} On MRI T1-weighted images, glomus tumours appear as low intensity subcutaneous tissue masses that enhance with gadolinium. On T2-weighted images, glomus tumours appear as high signal intensity masses.^{8 11 14}

Extradigital glomus tumours have a classic presentation of persistent and reproducible sharp, focal pain with associated cold sensitivity. When patients present with these symptoms, we recommend asking the patient to fill out a pain questionnaire to better characterise their pain symptoms. Ultrasound and MRI can be powerful diagnostic tools to help identify the presence of an underlying soft tissue mass. In addition, observing a patient’s response to injection of local analgesia at the site of pain can be informative—temporary relief of symptoms would support the diagnosis of a glomus tumour.¹¹ Definitive treatment of glomus tumours is en bloc surgical excision, which results in complete resolution of pain symptoms.

In this case, several healthcare providers persisted on a diagnosis of GTPS, despite no imaging findings to suggest the diagnosis and no symptom relief with standard GTPS therapy. It is important for care providers to maintain a wide initial differential diagnosis for causes of pain and to take a thorough pain history. Lastly, clinicians must validate a patient’s pain experience. Our patient felt her physicians did not take her complaints seriously, which added to the psychological distress she experience. To this day, despite expressing extreme gratitude for having her pain symptoms relieved, she still reports serious trauma from her experience.

Patient’s perspective.

In regards to the pain symptoms the patient endured for eight years, she said: ‘[the pain] was horrible. I didn’t want to wake up in the morning because I had pain non-stop. [It was] a nightmare for me, all of these years. No one believed me, not even my family doctor at first. They said I had arthritis. I know I’m not a doctor, but I have arthritis elsewhere and I knew that it wasn’t that. I knew something was wrong, I knew. The pain was non-stop for so long, but no one believed me.

Everything was difficult. Every single thing was difficult. The whole day was pain, non-stop. I had to walk to work, because I don’t drive. I used to love walking, and I was trying to walk with my pain. I would spend the whole day holding my leg. When I would take the bus, I would hold my leg, so that it wouldn’t hurt as much when the bus moved. I never took a day off. I was working with kids, bending and lifting all day. It was horrible. More than horrible. Almost ten years with this pain. Every 2–3 s I would have sharp pain, I couldn’t breathe. I don’t want to remember the pain that I had anymore. I don’t want anybody to go through what I went through.

I had a little pain after the surgery for 48 hours, which was normal, and then that’s it.

Now I am born again. When I walk, I am not walking, I am flying. Now I am more than happy.

Learning points.

• Extradigital glomus tumours are often misdiagnosed, which can lead to years of unnecessary suffering.

• Take a thorough pain history, (we recommend using a self-reported pain questionnaire to aid with this) and pay particular attention to localised, reproducible pain, as this points to an underlying anatomic pathology.

• Maintain a wide differential diagnosis, and reconsider your working diagnosis if symptoms are not improving with treatment. Consider extradigital glomus tumours on your differential if the pain is localised, reproducible and persistent.

• Use focused imaging of the affected region to search for underlying aetiologies. Ultrasound imaging (with or without Doppler) is an excellent first line tool for assessing soft tissue involvement. It is readily accessible, inexpensive, non-invasive and non-harmful. MRI is also an excellent imaging tool that can assist in diagnosis of glomus tumours.

• If a lesion is seen on imaging, refer to a surgeon.

Ethics statements

Patient consent for publication

Consent obtained directly from patient(s).