20-year-old female patient with a history of soft tissue mass in the posterior forearm for one year showing no change on size. On examination it was not movable and there was overlying skin discoloration.
MRI shows a dermal nodular mass extending to the skin surface, measuring 1 x 1 cm. The lesion is isointense relative to muscle on T1WI and isointense/intermediate signal relative to muscle on fluid-sensitive sequences.
On post-contrast images the lesion demonstrates moderate enhancement.
Superficial soft-tissue masses are common in clinical practice, and the expanding availability of the radiologic imaging has increased radiologists' familiarity with these entities [1].
Dermatofibrosarcoma protuberans is an uncommon spindle cell tumour, which typically arises in the dermis as a nodular mass, which then can spread into the subcutaneous tissue and muscle [2].
Dermatofibrosarcoma protuberans accounts for about 6% of all soft-tissue sarcomas [1, 3]. This lesion occurs between the third and the fifth decade of life. Lesions most commonly involve the trunk; up to half occur in this location. The extremities followed by the head and neck are the next most common sites, but tumours may occur on any part of the body [2, 3].
Patients often ignore these tumours because of their slow growth [2].
MR imaging is not routinely performed as part of the workup of patients with these neoplasms because of their characteristic appearance and superficial location [2, 3].
MR imaging is used to evaluate larger or atypical primary lesions or recurrent disease [3]. The lesions usually are manifested at MR imaging as unmineralised nodular masses with nonspecific signal intensity and moderate enhancement [1-3]. Areas of haemorrhage may be seen within the tumour [1].
Dermatofibrosarcoma protuberans has an excellent prognosis after complete resection but has a marked tendency to recur locally if inadequate surgical resection margins are obtained. Metastases are rare [2]. In our case the lesion was completely removed, histology was performed and established the diagnosis.
In conclusion, dermatofibrosarcoma protuberans is a rare, usually superficial soft-tissue sarcoma, which may be suspected on the basis of the tumour's clinical appearance. MR imaging helps to characterise atypical or difficult cases and may be important for pre-surgical planning.
Dermatofibrosarcoma protuberans
Based on the provided MRI images (axial and sagittal views) and histological slides, a soft tissue mass can be observed in the subcutaneous tissue of the posterior forearm:
Considering the patient’s young age, the slow growth of the mass, and its radiological and histological features, the following potential diagnoses are suggested:
Based on:
The final diagnosis is: Dermatofibrosarcoma Protuberans (DFSP).
The first-line treatment is complete surgical excision with adequate safety margins to minimize the risk of local recurrence. In confirmed cases, if pathological findings indicate positive or suspicious margins, a wider excision or combination therapy (e.g., radiotherapy) may be considered.
In this case, the patient has already undergone a complete surgical resection with a favorable prognosis. Regular postoperative follow-up is essential for early detection of any local recurrence.
Postoperative rehabilitation and exercise should be individualized and gradually progressed. The FITT-VP principle (Frequency, Intensity, Time, Type, Progression, Volume) is recommended:
If the patient has bone fragility, limited cardiopulmonary function, or other issues, exercise intensity should be reduced under the guidance of a physician or rehabilitation therapist, and the patient’s response should be closely monitored.
This report is a reference analysis based on the currently available information and cannot replace an in-person consultation or professional medical advice. For specific treatment and rehabilitation plans, please consult a specialist or qualified healthcare professional.
Dermatofibrosarcoma protuberans
