Systematic analysis of post-treatment soft-tissue edema and seroma on MRI in 177 sarcoma patients.

PURPOSE: To assess post-treatment subcutaneous edema, muscle edema, and seroma in MRI after soft-tissue sarcoma (STS) resection with regard to muscle involvement of STS and therapy. METHODS: In all, 177 patients were included and received 1.5-T MRI follow-up examinations after treatment. Post-treatment changes were classified according to type of therapy (therapy 1-surgery; therapy 2-surgery with radiation therapy) and primary tumor localization in soft tissue (localization 1, subcutaneous tissue; localization 2, muscle involvement). Subcutaneous and muscle edema were divided into three grades: grade 0, absence of edema; grade 1, low-to-moderate edema; and grade 2, high-grade edema. RESULTS: The mean age of the patients was 55.7 ± 18.2 years and the mean volume of the resected primary STS was 321.5 cm3. After therapy 1 of a sarcoma in localization 1, patients significantly more often showed low-grade subcutaneous tissue edema and an absence of muscle edema (p < 0.001) than high-grade edema. The risk for grade 2 subcutaneous tissue and muscle edema significantly increased with a tumor in localization 2 (RR = 2.58, p = 0.016 and RR = 15, p = 0.0065/RR = 2.05 , p = 0.021, respectively) and after therapy 2 (RR = 15, p = 0.0087 and RR = 2.05, p < 0.0001, respectively). Of the patients with sarcoma in localization 2, 88% developed grade 2 muscle edema after therapy 2; 40% of the patients developed post-treatment seroma. The risk for seroma is significantly higher after surgery and radiation therapy than after surgery alone (p < 0.001). CONCLUSION: High-grade postoperative subcutaneous and muscle edema are significantly associated with muscle involvement of primary STS both in patients with and without radiation therapy. The risk for seroma is significantly higher after surgery with additional radiation therapy than after surgery alone.

Appearance of recurrent dermatofibrosarcoma protuberans in postoperative MRI follow-up.

PURPOSE: To analyze the appearance of recurrent dermatofibrosarcoma protuberans (DFSP) in postoperative MRI follow-up and to assess the occurrence of postoperative soft tissue changes detected in MRI. METHODS: A total of 464 MRI follow-up scans of 32 patients with histologically proven diagnosis of DFSP were analyzed. MR imaging was performed using a 1.5T MRI system. Recurrent DFSP was examined for signal intensity, contrast behavior, appearance, and extent in MRI. RESULTS: The mean age of the patients was 44,5±17,1 years. Recurrences of DFSP occurred 26±23.3 months after primary tumor resection in the mean (Min.: 9, Max.: 60). In 25% of the patients (n = 8), recurrences of DFSP were detected. Recurrent DFSP most often showed a nodular and homogeneous configuration with well-defined borders and marked contrast enhancement, and a hyperintense signal in PD-weighted and turbo inversion recovery magnitude sequences. All recurrences were well detected in the follow-up MRIs regardless of the performed plastic surgery procedure. Lateral and depth margins had no significant impact on the local recurrence rate. In all, 88% of the patients developed subcutaneous tissue edema (p < 0.01), followed by muscle edema (34%, p = 0.02), and postoperative seroma (22%). CONCLUSION: Recurrent DFSP mainly appear uniform and clearly delimitable on MRI as nodular, homogeneous, and well-defined lesions with marked contrast enhancement. Therefore, MRI is a valuable tool for postsurgical follow-up. Nearly all patients develop subcutaneous edema after the resection of DFSP.

Malignant peripheral nerve sheath tumours in magnetic resonance imaging: primary and recurrent tumour appearance, post-treatment changes, and metastases.

PURPOSE: To analyse the appearance of primary and recurrent malignant peripheral nerve sheath tumours (MPNSTs) in magnetic resonance imaging (MRI) with a focus on configuration, and to assess the occurrence of loco-regional post-treatment changes and metastases during post-treatment follow-up. MATERIAL AND METHODS: Twenty patients with histologically proven MPNST underwent post-treatment 1.5 T MRI. Primary and recurrent MPNSTs were examined for configuration, contrast enhancement, extent, and signal intensity in MRI. Loco-regional post-treatment changes and information on metastases were extracted from the follow-up. RESULTS: MPNSTs occurred most often in the extremities (p = 0.006). Twenty per cent (n = 4) of the patients developed recurrences, with a total of 24 lesions. Recurrent MPNSTs were significantly smaller than primary MPNSTs (p = 0.003). Primary MPNSTs mostly occurred unifocally as multilobulated or ovoid and heterogeneous lesions with mostly well-defined borders. Recurrent MPNSTs purely occurred multifocally as mostly nodular (p < 0.001), multilobulated, or ovoid lesions. 80%, 65% and 30% of the patients showed post-treatment subcutaneous oedema (p = 0.002 to 0.03), muscle oedema (p = 0.02), and seroma, respectively. Twenty-five per cent (n = 5) of patients presented metastases during follow-up. The relative risk in patients with recurrences to develop lung or lymph node metastases is eightfold (p = 0.056). CONCLUSIONS: While primary MPNSTs mostly appear unifocally as multilobulated or ovoid lesions, recurrent MPNSTs purely occur multifocally as mostly nodular lesions. Subcutaneous and muscle oedema are very common loco-regional post-treatment changes. Patients with recurrences have a higher risk for lung and lymph node metastases.