A 52-year-old woman presented with a 4-year history of a palpable and painless mass in the dorsum of the right wrist. She had no history of trauma, and she didn’t refer pain or inflammation.
Ultrasonography revealed a well-defined anechoic mass, with internal septations, located within the first extensor digitorum communis tendon.
MR imaging was performed obtaining T1-weighted images and T2-weighted images on sagittal and axial planes. The scan demonstrated a well-demarcated fusiform cystic lesion located between the fibres of the first extensor digitorum communis tendon. Some internal septations were observed. No signs of haemorrhagic of inflammatory complication were found.
Background
Ganglion cysts are benign lesions that arise in collagenous tissues due to mucinous degeneration produced by persistent irritation, recurrent damage and ischaemia [1]. They are filled with mucinous fluid rich in hyaluronic acid and other mucopolysaccharides, surrounded by dense connective tissue, and lack synovial epithelial layer [1,2].
They are the most common cause of palpable lesions of the hand and wrist [3]. They are traditionally classified according to their origin: tendon sheath, joint, bone or soft tissue. The incidence of an intratendinous ganglion cyst that originates within the tendon substance itself is relatively rare [1].
Clinical Perspective
Ganglion cysts usually present as an asymptomatic palpable mass. Occasionally, depending on their size and location, they may cause pain and mass effect [1]. Due to the rarity of the intratendinous location, it is difficult to suspect it fully based on the physical examination.
Imaging Perspective
Imaging plays an essential role in determining the composition of the palpable mass and its specific location. MRI and ultrasound are highly sensitive and specific methods for determining the cystic nature of the lesion, its size, location and relationship to the surrounding structures [1,3].
Ganglion cysts appear as well-demarcated rounded lesions, filled of fluid and often with sharply defined internal septations. On ultrasound, they appear as a well-defined anechoic mass with posterior acoustic enhancement due to its fluid composition [3].
On MRI they have homogeneous high-intensity signal on T2WI with a thin peripheral rim and often some internal septations. Intensity signal on T1WI is variable, being hyperintense if they have higher proteinaceous or haemorrhagic content. After gadolinium administration, they may show enhancement of the peripheral rim and septations, with no internal enhancement [2].
They might complicate with bleeding or inflammation. Haemorrhagic cysts may show a more heterogeneous appearance with low or bright internal signal intensity depending on the evolution of bleeding. If inflamed or infected, they may have a thickened outer lining or internal septa, as well as some degree of pericystic oedema. However, they should not demonstrate internal enhancement after intravenous contrast administration [2].
Outcome
Surgical excision is usually the first-choice treatment and consists of en bloc resection of the affected tendon to reduce recurrence. Our patient decided to maintain an expectant attitude due to the lack of disabling symptomatology.
Teaching Points
Intratendinous ganglion cysts are rare lesions with difficult clinical diagnoses. Therefore, ultrasonography and MR imaging are essential tools for determining the accurate diagnosis and planning the appropriate treatment.
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Intratendinous ganglion cyst of the first extensor digitorum communis tendon
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Based on the ultrasound and MRI images provided by the patient for the dorsal aspect of the right wrist, the following features are noted:
Considering the patient’s clinical details (52-year-old female with a painless, palpable dorsal wrist mass for 4 years) alongside the imaging findings, the possible diagnoses include:
Taking into account the patient’s age, clinical presentation (long-standing, painless mass on the dorsal wrist tendon area), and the characteristic cystic features on imaging, the most likely diagnosis is:
Intratendinous Ganglion Cyst.
This aligns with the pathological mechanism of a cyst developing within or adjacent to tendon collagen tissue, consistent with both MRI and ultrasound findings. Further confirmation can be achieved through image-guided aspiration or histopathological analysis, though clinical diagnosis combined with imaging is typically adequate.
The choice of treatment will depend on the severity of symptoms and the patient’s preferences.
When the cyst is asymptomatic or following surgery, progressive exercises targeting wrist and forearm muscle strength and flexibility may be beneficial. Adherence to the FIT(T)-VP principle (Frequency, Intensity, Time, Type, Volume/Progression) is recommended:
• Frequency (Frequency): Perform exercises 3-4 times per week, adjusting as tolerated.
• Intensity (Intensity): Begin with low-resistance or low-load activities (e.g., using a grip ball, gentle circular wrist movements) and incrementally increase the load or repetition count.
• Time (Time): Start with 10-15 minutes per session and gradually extend to 20-30 minutes.
• Type (Type): Focus on wrist function movements such as repeated fist/open hand drills, wrist flexion/extension, and forearm pronation/supination, combined with mild stretching.
• Volume/Progression (Volume/Progression): Slowly ramp up exercise volume or load to prevent sudden strain on the tendons or joints.
If the patient has other conditions (e.g., osteoporosis or arthritis), exercise intensity should be adjusted accordingly, with symptoms closely monitored. A rehabilitation specialist or exercise therapist may offer individualized training guidance if necessary.
Disclaimer: This report is based on the currently available information and is provided for reference only. It does not constitute a definitive diagnosis or prescription. If you have questions or if your condition changes, please seek timely medical attention and assessment by a qualified physician.
Intratendinous ganglion cyst of the first extensor digitorum communis tendon
