The patient, a 17-year-old female, noticed a swelling in the right supraclavicular region while taking a selfie. The swelling showed a gradual increase in size in the following months. On examination, she experienced no restricted mobility or pain in the neck and shoulder.
To investigate the lesion, imaging with ultrasound and MRI was performed.
Ultrasound revealed a hyperechogenic, heterogeneous, well-circumscribed mass with a diameter of 6 cm, located retroclavicular and antero-inferior to the trapezius muscle (Figure 1a). The solid lesion showed infraclavicular expansion, although no invasion of the surrounding muscles was observed. Colour Doppler showed limited vascularisation, which was predominantly venous flow. A focal calcification, possibly a phlebolith, was noted (Figure 1b).
T2-weighted images showed a moderate-to-high intense lobulated mass with fibrous septations (Figure 2a). Multiple low-intense structures, presumably phleboliths, were observed within the lesion (Figure 2b). On T1-weighted images, the mass showed discrete adipose septations in the periphery and had surrounding fatty tissue (Figure 2c). Heterogeneous enhancement was observed after administration of gadolinium-based contrast (Figure 2d).
After surgical resection, histopathological examination confirmed the diagnosis of a fibro-adipose vascular anomaly.
Background
Fibro-adipose vascular anomaly (FAVA) is a rare vascular anomaly with distinct radiologic and histopathologic features. FAVA is characterised by fibrofatty infiltration of muscle tissue and abnormally dilated veins (phlebectasia). The lesions most commonly present in the lower extremities and forearms [1–3].
The lesions are sporadic and most often caused by mutations in the PIK3CA gene, which leads to an overgrowth in fibrous and adipose tissue, as well as angiogenesis and lymphangiogenesis [4].
Clinical Perspective
FAVA affects young people, between the ages of 1 and 30, with a female-to-male ratio of 4:1. Patients usually present with constant pain and functional impairment of the affected muscles, such as limited mobility and contractures [2]. However, in our case, the patient was asymptomatic.
Because clinical symptoms are nonspecific, further imaging investigations are needed.
Imaging Perspective
On ultrasound, FAVA appears as a heterogeneous, hyperechogenic mass. Abnormal ectatic veins are frequently observed within the lesion, as well as phleboliths and venous thrombosis. In contrast to venous malformations, FAVA is more solid and has less compressible spaces. Colour Doppler shows minimal venous flow [2,4,5].
MRI can help further differentiate FAVA from other vascular anomalies. Fibrofatty infiltration of the surrounding muscle tissue appears as heterogeneous hyperintense on T2-weighted images, though less intense compared to venous malformations. The fatty component is highlighted on T1-weighted images. After administration of gadolinium-based contrast, the lesions show heterogeneous enhancement [2,4,5].
Contrary to typical presentations described in the literature, the FAVA lesion in our case did not show fibrofatty infiltration of muscle tissue. Furthermore, the neck-shoulder region is quite an unusual location for FAVA.
Because clinical and imaging features can overlap with other vascular anomalies, histopathological examination is often required to confirm the diagnosis.
Outcome
It is important to differentiate FAVA from common venous malformations because the former is associated with more functional impairment if left untreated.
FAVA lesions are benign and often localised. Surgical resection is considered an effective long-term curative option, despite its difficulty with larger, more infiltrative lesions. Other treatment options to reduce symptoms include sclerotherapy, cryoablation, drug therapy and physiotherapy [3,4].
Take Home Message
FAVA is a rare and often misdiagnosed vascular anomaly in young patients. On imaging, it typically appears as a heterogeneous, solid mass with fibrofatty infiltration of muscle tissue. Dilated veins, phleboliths and slow venous blood flow are often observed. Surgical resection is the most effective treatment, though other options are available to reduce symptoms.
All patient data have been completely anonymised throughout the entire manuscript and related files.
Fibro-adipose vascular anomaly
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
From the provided ultrasound images, there is a relatively ill-defined heterogeneous soft tissue lesion in the right supraclavicular area. Internally, the echoes are uneven, and there are localized hypoechoic or mixed echoic zones; on examination, a small number of abnormally dilated veins can be seen. Color Doppler shows weak blood flow signals within the lesion, primarily suggesting chronic venous flow or local blood stasis.
MRI images show the lesion located within the soft tissues of the neck and shoulder. On T2-weighted images, the lesion appears relatively hyperintense, and some areas show high fat content signals; on T1-weighted images, the lesion exhibits slightly high or intermediate-high signal intensity, with heterogeneous enhancement. Compared to typical vascular lesions, this lesion shows more fibrous and fatty infiltration. Overall, the signal differences across different sequences indicate that the lesion contains fibrous, fatty, and vascular components.
Considering the patient’s age, sex, lesion location, imaging characteristics (fibro-adipose components and abnormal vascular dilation), and the clinical presentation of gradual growth without significant functional impairment, the most likely diagnosis is:
Fibro-adipose Vascular Anomaly (FAVA).
If any diagnostic uncertainty remains, further histopathological examination is recommended to confirm the diagnosis.
1. Treatment Strategy Overview:
(1) Surgical Excision: For lesions with well-defined borders or smaller volume that can be completely removed, surgical resection can be considered. This approach can be curative, but the risk of surgical trauma and potential injury to important nerves or vessels must be assessed.
(2) Interventional Treatments and Other Management: This may include sclerotherapy, cryoablation, and medication (such as mTOR inhibitors or PI3K pathway-related drugs). These options can reduce symptoms or slow lesion progression, typically applied in cases with large lesions or when complete resection is not feasible.
(3) Physical Therapy and Rehabilitation: In patients without significant functional impairment or with only mild symptoms, early conservative management includes monitoring disease progression and applying appropriate rehabilitation exercises to maintain shoulder and neck mobility and muscle strength.
2. Rehabilitation/Exercise Prescription (FITT-VP Principle):
(1) Frequency: Perform 2–3 sessions per week targeting light strength and range-of-motion exercises for the neck, shoulders, and upper limbs.
(2) Intensity: Initially, use low resistance and low load or only bodyweight for isometric or small-range movements, with the goal of avoiding significant pain.
(3) Time: Begin each session with a 5–10-minute warm-up that includes active neck and shoulder movements; the main exercise should last approximately 15–20 minutes; conclude with about 5 minutes of stretching or relaxation.
(4) Type: Consider gentle neck and shoulder range-of-motion exercises, such as gentle head and neck rotations, shoulder circles, or band-assisted presses to maintain or slightly increase muscle strength and mobility.
(5) Progression: Once the patient adapts, gradually increase the range of stretches and movements or increase the resistance of the exercise band. Maintain proper form and avoid overload. If there is significant local pain or swelling, seek medical evaluation promptly.
(6) Volume: Divide exercises into 2–3 sets, each set comprising 8–12 repetitions. As tolerance improves, sets or repetitions can be slightly increased.
Throughout rehabilitation, close attention should be paid to the stability of the neck-shoulder region and the local vascular lesion, avoiding high-intensity or extreme joint movements that could cause increased compression or irritation. For those with notable hemodynamic changes or a higher risk of local vascular malformations, careful assessment is required before engaging in more intensive activities.
Disclaimer: This report is based solely on the provided medical history and imaging data. It is not a substitute for an in-person consultation or professional medical advice. If you have any concerns or experience discomfort, please consult a qualified healthcare provider immediately.
Fibro-adipose vascular anomaly
