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Is Neoadjuvancy with Imatinib Useful Before Mohs Surgery in Locally Advanced Dermatofibrosarcoma Protuberans?
A Bota-Llorca1,2, B Llombart-Cussac1,2, C Serra-Guillén1,2
1Doctoral School, Catholic University of Valencia San Vicente Mártir, 46001 Valencia, Spain.
Abstract:
Dermatofibrosarcoma protuberans (DFSP) is a rare cutaneous sarcoma in which complete surgical excision is standard treatment, although some tumors are initially unresectable. Neoadjuvant imatinib has been proposed in these cases, but data on its histopathological and molecular effects and long-term outcomes remain limited. To evaluate the clinical, histopathological and molecular impacts of neoadjuvant imatinib prior to modified Mohs surgery (MMS) in locally advanced DFSP. Single-center, retrospective study. After a mean of 10 months of neoadjuvant imatinib, partial tumor size reduction was observed in 60% of patients (mean reduction 37.8%), while the remaining cases showed disease stabilization; no complete responses were recorded. All tumors exhibited marked volumetric and consistency reduction, with histology revealing extensive hypocellular hyaline regression and attenuated CD34 and nestin expression. Persistence of COL1A1-PDGFB fusion transcripts was detected in post-treatment samples. Following MMS, local recurrence occurred in 30% of patients at long-term after a mean of 10.8-year follow-up since the last surgery. Neoadjuvant imatinib in locally advanced DFSP results in tumor volume reduction without decreasing the final surgical defect. The histological response is typically patchy and may compromise detection of residual disease, potentially increasing the risk of local recurrence.
Insights
Neoadjuvant imatinib reduced dermatofibrosarcoma protuberans (DFSP) tumor size but did not eliminate it. Histological changes may increase local recurrence risk after surgery.
Area of Science:
- Oncology
- Dermatology
- Surgical Pathology
Background:
- Dermatofibrosarcoma protuberans (DFSP) is a rare skin cancer.
- Complete surgical excision is the standard treatment.
- Some DFSP tumors are unresectable and may benefit from neoadjuvant therapy.
Purpose of the Study:
- To assess the clinical, histopathological, and molecular effects of neoadjuvant imatinib before modified Mohs surgery (MMS) in locally advanced DFSP.
- To evaluate long-term outcomes after this treatment approach.
Main Methods:
- Single-center, retrospective study.
- Patients received neoadjuvant imatinib for a mean of 10 months prior to MMS.
- Clinical, histological, and molecular analyses were performed.
Main Results:
- 60% of patients showed partial tumor size reduction (mean 37.8%); others had stable disease.
- Tumors exhibited significant volume and consistency reduction with hypocellular hyaline regression.
- CD34 and nestin expression attenuated; COL1A1-PDGFB fusion transcripts persisted.
- Local recurrence occurred in 30% of patients after a mean 10.8-year follow-up.
Conclusions:
- Neoadjuvant imatinib reduces DFSP tumor volume but not the final surgical defect size.
- Histological response is patchy, potentially hindering residual disease detection and increasing recurrence risk.
