Title

An extraordinary case of dermatofibrosarcoma protuberans with recurrent pancreatic metastases

Authors

Nouman Aziz¹, Yasmine Elsherif², Waseem Nabi¹, Ahmad Basharat³, Adnan Bhat4, Reddy Ramachandra¹ :: ¹Wyckoff Heights Medical Center ²Zayed Military Hospital, UAE ³Marshfield Clinic Health System 4University of Florida, Gainesville

Introduction

Dermatofibrosarcoma protuberans (DFSP) is a rare, low-grade skin tumor classified as a soft tissue sarcoma, with an annual prevalence of 0.8–4.5 cases per million. Originating in the dermis, it gradually invades the subcutaneous fat and is most commonly found on the trunk (42%), followed by the limbs (21%) and head and neck (13%). While DFSP occurs equally among genders, some studies suggest a slight male predominance, and it is more prevalent in individuals of black ethnicity. The fibrosarcomatous variant (DFSP-FS), described by Mentzel et al. in 1998, is a high-grade subtype associated with increased recurrence, a higher risk of distant metastases (8–29%, typically to the lungs), and a more aggressive clinical course. Metastases to the pancreas are exceedingly rare. We report a case of DFSP-FS metastasizing to the pancreas 10 years after resection of the primary tumor in the anterior abdominal wall.

Case Presentation

A 43-year-old male with history of resected anterior abdominal wall mass in 2013, diagnosed as dermatofibrosarcoma protuberans with focal fibrosarcomatous transformation (DFSP-FS), presented in July 2021 with a dry cough. Imaging revealed a right lower lung lobe mass. Following lobectomy in August 2021, pathology confirmed metastatic DFSP-FS. During routine follow-up, a CT scan revealed a cystic lesion in the pancreatic body measuring 25 × 31 × 29 mm, abutting the splenic artery. MRI showed progression to 50 × 33 × 44 mm without biliary obstruction. Laboratory findings, including liver function tests and CA 19-9, were normal. Endoscopic ultrasound-guided biopsy revealed spindle cells positive for CD34 and negative for CD117 and pancytokeratin, consistent with metastatic DFSP-FS. PET/CT ruled out additional metastases. Following tumor board discussion, the patient underwent robotic-assisted distal pancreatectomy. Pathology confirmed clear margins, and no lymph node metastases were identified. The patient completed radiotherapy in January 2024. As of September 2024, he remains clinically recurrence-free, opting for observation over further imaging.

Discussion

This case highlights the aggressive nature of DFSP-FS, which has a higher metastatic potential compared to classic DFSP. While lung metastases are well-documented, pancreatic involvement, as observed here, is exceedingly rare. The nearly decade-long delay in metastasis emphasizes the indolent but unpredictable progression of DFSP-FS. Surgical excision remains the cornerstone of management. In this case, robotic-assisted distal pancreatectomy achieved clear margins, underscoring the role of meticulous surgical planning. While tyrosine kinase inhibitors like imatinib are effective in unresectable disease, their post-surgical role in DFSP-FS is not well-defined. Chemotherapy, although considered, was not pursued due to limited evidence and patient preference. This case emphasizes the importance of long-term surveillance for DFSP-FS patients and awareness of atypical metastatic patterns. Multidisciplinary care and individualized treatment strategies remain critical to optimizing outcomes in such rare and challenging presentations.

References

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