Mrs B is a lovely, very active, very fit 60-year-old lady who was initially referred to us because of a large ganglion on the dorsum of her right foot. Her main problem was that the ganglion was rubbing on most types of footwear, and it had increased in size over the last few months. There was no history of trauma, nor history of lumps or bumps elsewhere nor any malignant conditions.
Mrs B had seen a podiatrist, who had very appropriately trialled some footwear changes as well as some padding and offloading to the right foot. This had initially relieved her symptoms, but as the ganglion increased in size her pain got worse so she was referred by her General Practitioner for review.
Clinically, there was a large, translucent lesion on the dorsum of the foot but also some sensory changes in the area of the superficial peroneal nerve distribution, on the third, fourth and fifth toes of her right foot. Given the size of the lesion and neurological involvement, an MRI was ordered (see below).
Although extremely rare, a large soft tissue lesion (>5cm) in the deep tissues may be a soft tissue sarcoma. It is important to liaise with an experienced musculoskeletal radiologist as well as a musculoskeletal tumour surgeon if there is any potential for malignancy on imaging or examination.
In the setting of malignancy, a biopsy is required for histopathological diagnosis and staging. If biopsy or surgery is performed and not done in consultation with a tumour surgeon, seeding of the tumour may result and wider excision required when the tumour is eventually excised in entirety. In this instance, it was confirmed that this lesion was a ganglion radiologically and clinically prior to proceeding with the planned aspiration.
A few days after the MRI scan, Mrs B's granddaughter stood directly on her right foot, effectively decompressing the ganglion. This was incredibly painful for Mrs B, but did have the benefit of reducing the size of the ganglion and after the initial trauma resolved the ganglion was much smaller and her neurological symptoms improved.
As the ganglion was effectively mechanically decompressed, an ultrasound guided aspiration was not performed, although an ultrasound guided aspiration is appropriate first-line intervention for this condition.
Unfortunately after a few weeks the ganglion recurred and again increased in size so the decision was made to proceed with surgical excision.
The procedure was relatively uncomplicated, although the ganglion was very serpentine in its anatomical appearance and the superficial peroneal nerve was intimately intertwined with the lesion.
The ganglion was sent for histopathology as well as microscopy and culture with review by a pathologist experienced in musculoskeletal tumours, who confirmed a ganglion.
Mrs B was reviewed 6 weeks following her surgery, and demonstrated complete decompression of the ganglion and resolution of all her symptoms. She was discharged from our care at that stage.
As can occur with large ganglions, Mrs B had a recurrence of the ganglion approximately 9 months following her original surgery. At that stage, it was not bothering her particularly much, so we both decided to treat her recurrence non-operatively.
After a period of months, the ganglion continued to grow in size, so we elected to proceed with revision excision of the ganglion.
The complications continued for poor Mrs B post operatively. She had a lot of neuropathic pain following the revision procedure, and there was some concern that the superficial peroneal nerve may have been caught up in the scar tissue or sutures over the dorsum of the foot. Some local anaesthetic was therefore applied for removal of sutures, but Mrs B then developed an acute hypotensive, potential anaphylactic reaction to the local anaesthetic and an ambulance was called. Adrenaline was not required as she remained conscious, normalised her blood pressure and heart rate, and had a patent airway (although we did have our anaphylaxis trolley containing adrenaline, bronchodilators, large bore IV cannulas, normal saline plus the defibrillator handy!), but she was monitored in the emergency department for several hours after the event.
Despite this, Mrs B recovered well from her surgery and five months following her revision procedure is back to her regular busy life, with no pain in her foot.
Discussion
First line treatment of a ganglion to the foot or ankle should be allied health involvement for simple footwear changes to avoid unnecessary pressure on the lump. An ultrasound guided aspirate is appropriate for initial treatment but an MRI should be considered prior to aspiration for lesions greater than 5cm or in the deep tissues to exclude malignancy. Recurrence after ganglion aspiration is as high as 50%.
Recurrence of a ganglion can still occur after surgical excision in approximately 10% of patients. The inadvertent decompression of the ganglion by the patient's granddaughter may have perforated the capsule of the ganglion making recurrence more likely in this particular case.
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