A 50-year-old patient with suspected carpal tunnel syndrome had an MRI performed. A soft tissue mass involving the median nerve and the flexor retinaculum was reported.
The ultrasound revealed an hypoechoic lesion at the volar side of the hand surrounding the flexor tendons, and Doppler colour showed rich vascularisation of the lesion (Fig 1).
An MRI was performed demonstrating a rounded lesion surrounding the flexor tendons of the hand and also the median nerve. At the T1-weighted image it proved to be little hyperintense compared to the muscle (Fig. 2), and hyperintense at T2 Fat-sat weighted image (Fig 2). After injection of gadolinium the lesion showed avid peripheral enhancement (Figs. 4 and 5), maybe due to the myxoid component located in the middle of the lesion. All these findings suggested a soft tissue tumour or a tumour-like lesion, therefore a biopsy was recommended.
Nodular fasciitis is the most common benign tumour or tumour-like lesion of fibrous tissue. It usually affects adults between 20-40 years-old and the most common location is the upper extremity, particularly the volar aspect of the forearm. This benign entity is a common pseudosarcomatous fibroblastic proliferation of unknown origin, probably representing a reactive lesion secondary to trauma and recently proved to be a true neoplastic origin due to a chromosomal mutation [1-3].
Pathological diagnosis of nodular fasciitis can be challenging, as these lesions, with their rich cellularity, high mitotic activity, and rapid growth, can mimic aggresive tumours as soft tissue sarcomas [1, 3, 4]. Histologically it can be categorised as myxoid, cellular, or fibrous, according to the predominant histologic feature of the lesion.
There are three described subtypes of nodular fasciitis based on the location of the lesion: subcutaneous, intramuscular, or fascial. The most frequent location of nodular fasciitis is the subcutaneous region being usually fascial lesions with well circumscribed margins easy to biopsy or excision. Lesions of the intramuscular and some fascial subtypes are usually larger, tend to be deeper and have poorer delimited margins conferring an aggressive appearance and mimicking soft-tissue malignancies [1, 3, 4].
As nodular fasciitis can present with a wide range of histological features, these lesions have variable MR imaging appearances, but are usually isointense to the skeletal muscle on T1-weighted images and hyperintense to adipose tissue on T2-weighted images.
Lesions with a predominant fibrous component may have a hypointense signal on all MR images. Postcontrast sequences show typically diffuse enhancement but it may be peripheral in lesions with myxoid matrix or a central fluid-filled component [1, 3, 4].
Surgery is almost curative in all cases only being reported a 1% incidence of recurrence [1, 3, 4]. Involution and spontaneous regression has also been described as the natural history of the disease [3] of nodular fasciitis in response to steroid injections have also been reported [5].
Finally the patient of our case underwent surgery with total excision and reconstruction. No recurrence has been reported since surgery.
Fascial nodular fasciitis
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The patient is a 50-year-old female who underwent MRI examination due to suspected carpal tunnel syndrome. The images demonstrate a soft tissue lesion on the palmar side of the wrist (near the median nerve and flexor retinaculum). MRI sequences show the overall signal and enhancement characteristics as follows:
Based on the imaging features and clinical symptoms, the following differential diagnoses should be considered:
Considering the patient’s age (50 years old), clinical presentation (compression symptoms of the median nerve at the wrist), growth pattern of a benign fibrous lesion in the soft tissue, any pathological findings (if biopsy or surgical pathology is available), and corresponding imaging features, the most likely diagnosis is:
Nodular Fasciitis.
If there is still diagnostic uncertainty, an intraoperative frozen section examination or complete excision followed by further pathological assessment may be performed to rule out other malignant or aggressive lesions.
Treatment Plan:
Rehabilitation Program (FITT-VP Principle):
Please note that exercise progression should consider the patient’s overall condition (e.g., bone density, cardiopulmonary health). Always adhere to safety guidelines and consult with a rehabilitation physician or therapist if there are any concerns.
This report is a reference based on the current clinical and imaging data and does not replace in-person consultation or professional medical advice. In case of any doubts or changes in the patient’s condition, please consult a specialist promptly.
Fascial nodular fasciitis
