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CASE REPORT
The 30-year wait for treatment of an acutely
painful knee
Dominic Davenport, Henry B Colaco, Max R Edwards
Department of Trauma and
Orthopaedics, Princess Royal
University Hospital, King’s
College Hospital NHS
Foundation Trust, London, UK
Correspondence to
Dominic Davenport,
dominic.davenport@nhs.net
Accepted 8 September 2014
To cite: Davenport D,
Colaco HB, Edwards MR.
BMJ Case Rep Published
online: [please include Day
Month Year] doi:10.1136/
bcr-2014-206512
SUMMARY
A 63-year-old retired man presented to our clinic
reporting a severely painful, localised knee pain present
for around 30 years and associated with a spontaneous
palpable lump. He was prompted to seek medical advice
at this point because his symptoms were exacerbated
when his young grandchildren bumped into the knee.
While radiographs were unhelpful, ultrasonography
revealed a well-defined, subcutaneous soft tissue mass
at the anterior aspect of the knee. Surgical excision was
performed as a day case. Histological examination of the
mass showed a glomus tumour. This patient had
suffered for many years as a result of this painful mass
but full resolution of his pain occurred immediately after
excision.
BACKGROUND
This is a rare case of a symptomatic glomus tumour
of the knee. There was a delay of around 30 years
until diagnosis but once excised there was immedi-
ate resolution of the pain. We therefore suggest
general practitioners, accident and emergency
doctors and orthopaedic surgeons should consider
a glomus tumour as a differential diagnosis in cases
of painful lumps around the knee. Prompt referral
to an orthopaedic surgeon recommended given the
excellent prognosis following excision.
CASE PRESENTATION
An independent 63-year-old male patient presented
to our clinic for an opinion about his exquisitely
painful knee. He had worked in the financial sector
and had a history of mild hypertension and hyper-
cholesterolaemia controlled on medication.
His knee pain had persisted for around 30 years
but had recently become more troublesome as his
young grandchildren were prone to bumping into
his knee causing severe pain over the lump. The
patient found direct impact to the lump unbearable
even to light touch. There were no mechanical
symptoms of the knee to suggest intra-articular
pathology. Examination revealed a well-defined,
subcutaneous, mobile mass on the anterior aspect
of the knee superficial to the patellar tendon. It
had the clinical appearance consistent with a
lipoma but was exquisitely tender to palpation.
INVESTIGATIONS
Radiographs of the knee in anterioposterior and
lateral were unremarkable, however, ultrasound
scan showed a 2.2×1.1 cm well-defined heteroge-
neous mass with well-defined borders at the
anterolateral aspect of the knee adjacent to the
patellar tendon (figure 1).
DIFFERENTIAL DIAGNOSIS
Given the appearance and examination finding of a
soft, mobile, well-defined lump it would be reason-
able to consider a subcutaneous lipoma as the differ-
ential diagnosis. Differential diagnoses of non-tender
masses around the knee include ganglion cysts which
are commonly found in Hoffa’s fat pad and synovial
cysts, including the commonly known Baker’scyst.
Synovial cysts are lined by synovial tissue unlike other
juxta-articular cysts and occur due to a diverticular
outpouching which is eventually pinched off at the
neck.
1
Both of these cystic masses may present as a
palpable, fluctuant mass around the knee but are
rarely symptomatic with pain.
The presence of exquisite tenderness on palpa-
tion or pressure broadens the differential diagnosis.
While pain from a lipoma is unusual, angiolipomas
and neuromata have been reported as painful.
Previous cases have reported that in the context of
trauma or operative intervention to the medial
aspect of the knee a painful neuroma may arise due
to the subcutaneous course of the infrapatellar
branch of the saphenous nerve.
2
Soft tissue sarcomatous pathology should always
be considered, but in this case the chronicity of
symptoms decreased the likelihood of this diagnosis.
TREATMENT
After investigation, open excision of the mass
under general anaesthetic was performed as a day
case procedure. The procedure showed that the
mass was subcutaneous, well defined and extended
down to the level of the patellar paratenon with no
Figure 1 Ultrasound examination of the mass in the
sagittal plane.
Davenport D, et al.BMJ Case Rep 2014. doi:10.1136/bcr-2014-206512 1
Reminder of important clinical lesson
intra-articular extension. The mass was excised intact with clear
margins on clinical inspection.
OUTCOME AND FOLLOW-UP
The patient returned to clinic 2 weeks later delighted that his
pain had immediately resolved. His wound was well healed and
he had suffered no adverse effects of the surgery. Percussion of
his patellar tendon was pain free for the first time in 30 years.
Histological examination revealed a glomus tumour of the knee
(figures 2 and 3).
DISCUSSION
Glomus tumours are usually benign hamartomatous masses
thought to be of neuromyoarterial origin.
34
Many clinicians
will be aware of these tumours as a differential diagnosis in the
acutely tender subungal mass of the digit. Indeed, glomus
tumours are by far most commonly found in the hand.
5
It has
been estimated that glomus tumours are seen in the lower limb
in only 1.6% of cases
3
and review of the specialist orthopaedic
literature shows only a handful of reports of glomus tumours of
the knee.
6
The first description of the distinct clinical features of these
tumours supported by histological diagnosis was by Masson.
6
Consistent presenting features are acute pain and tenderness
even to light touch, some have a visible reddish blue tinge and
cold exacerbation is commonly reported.
7
The latter feature is
likely to be linked to the role of normal glomus tissue in
cutaneous temperature regulation.
68
Many of the case reports
of glomus tumour of the knee highlight that due to the low clin-
ical suspicion and list of possible differential diagnoses, there is
commonly a delay in the diagnosis, therefore delaying treat-
ment. In one case study the patient underwent diagnostic
arthroscopic surgery as osteoarthritis was thought to be the
cause of the pain. It was only following a negative arthroscopy
and subsequent MRI scan that a glomus tumour was diagnosed
and treated.
9
Clinical tests for glomus tumour reported in the literature
include tenderness on direct localised pressure over the mass,
10
and resolution of tenderness in response to ischaemia with
infiltration of bupivacaine
11
or application of a limb
tourniquet.
12
Imaging via radiograph fails to show glomus tumours and
even ultrasound has been shown to only detect 8 of 17 glomus
tumours in one study.
13
In our case ultrasound scan was effect-
ive in detecting the mass and the reporting radiologist was able
to comment on specific features which were consistent with a
benign mass, however, was not specific for glomus tumour.
Previous case reports of glomus tumours of the knee have
reported that MRI was an effective tool in identifying the
underlying mass but are, like ultrasound scan, non-specific.
14
In conclusion, glomus tumours of the knee are uncommon
and only previous reported in specialist orthopaedic literature.
They are often exquisitely painful and the impact to the patient
of early diagnosis, referral to an orthopaedic knee surgeon and
timely surgical excision cannot be underestimated. We follow
this case report with the patient’s perspective.
Patient’s perspective
In my late 20s a lump appeared below my right knee—for no
apparent reason. It was about 2.5 cm across and 1 cm in depth
and its size remained unchanged for over 30 years. It was
extremely tender and even the slightest touch would cause me
excruciating pain. Rough and tumble games with my small
children were often a very painful experience and even a slight
brush against a plant when gardening would double me up in
pain. I became very aware of my right knee and very defensive
about it. I also occasionally suffered shooting pains up the right
side of my body emanating from my right knee, which occurred
for no discernible reason and usually when I was lying on the
bed.
My general practitioner said that nothing could be done,
because, if the lump was removed, it would only grow back.
I, therefore, developed coping mechanisms to protect my
knee, such as placing my hand over it when commuting in
crowded train carriages or crossing my legs in company—but
not always with success and the air has been known to turn
blue!
Since the lump was removed in 2013 when I was 63, I have felt
no pain when the area below my right knee is touched even
firmly and the occasional shooting pains have stopped.
Psychologically this has improved my life significantly. I have
become much more relaxed, especially in the company of my
small grandchildren and their dog (with a very waggy tail) and
can now enjoy their company without the constant fear that a
stray arm or leg (or tail) will inadvertently double me up in
excruciating pain.
Figure 2 H&E stain.
Figure 3 Immunohistochemistry—Smooth Muscle Actin stain.
2 Davenport D, et al.BMJ Case Rep 2014. doi:10.1136/bcr-2014-206512
Reminder of important clinical lesson
Learning points
▸The knee is an uncommon site for glomus tumour to present.
▸The diagnosis of glomus tumour of the knee may be missed
and therefore remain untreated.
▸Glomus tumours often have a well-described history of
exquisite pain, local point tenderness and cold exacerbation.
▸Case reports have shown that ultrasound scan and MRI are
useful imaging modalities for detecting masses around the
knee but both tools are non-specific for glomus tumour.
▸In this case day case excision resulted in immediate
resolution of symptoms.
Acknowledgements The authors thank Dr Hasina Ahmad, Consultant
Histopathologist at Princess Royal University Hospital, for supplying photogaphs of
the histopatholoy slides.
Contributors All three authors have been involved in; conception and design,
acquisition of data or analysis and interpretation of data; drafting the article or
revising it critically for important intellectual content. Final approval of the version
published.
Competing interests None.
Patient consent Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.
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Davenport D, et al.BMJ Case Rep 2014. doi:10.1136/bcr-2014-206512 3
Reminder of important clinical lesson
