Solitary fibrous tumors (SFTs) are rare mesenchymal neoplasms predominantly arising from the pleura but occasionally occurring in extrapleural locations. Pulmonary parenchymal SFTs of extreme size are exceedingly uncommon and present diagnostic and therapeutic challenges. We report the case of a 60-year-old female with a 14 x 12 × 23 cm pulmonary SFT presenting with a two-week history of productive cough and significant weight loss. Imaging revealed a massive heterogeneous mass in the left lower lobe, compressing lung parenchyma, causing pleural effusion and atelectasis, and raising concerns for metastatic spread to the liver and spleen. Histological examination confirmed the diagnosis of SFT, with spindle-cell morphology and positive immunohistochemical staining for CD34 and STAT6. Despite the tumor's size and compressive effects, histopathology showed no necrosis, pleomorphism, or high mitotic activity, indicative of a non-aggressive phenotype. The patient underwent successful surgical resection via thoracotomy and is under long-term follow-up. This case highlights the unique diagnostic complexity of SFTs, particularly with tumors of exceptional size. While larger SFTs often suggest malignant potential, the absence of typical markers of malignancy in this case emphasizes the unpredictable behavior of these tumors. Imaging and immunohistochemical evaluation are critical for diagnosis, and surgical resection remains the cornerstone of management. This rare case underscores the importance of thorough diagnostic evaluation and surgical management in addressing giant pulmonary SFTs. Despite their potential for malignant transformation, careful histopathological analysis and multidisciplinary collaboration can guide optimal treatment and long-term surveillance for these unpredictable tumors.

Background: Dermatofibrosarcoma Protuberans (DFSP) is a rare, low-grade soft tissue sarcoma with a low risk of distant metastasis. The fibrosarcomatous variant (DFSP-FS) exhibits more aggressive behavior, an increased potential for metastasis to uncommon sites. Case presentation: We present the case of a 43-year-old African male with a history of resected anterior abdominal wall DFSP-FS, who developed pancreatic metastases ten years postresection. The patient initially presented with a lung mass, which was confirmed as metastatic DFSP-FS after lobectomy. A subsequent cystic pancreatic lesion was incidentally detected during routine imaging. An endoscopic ultrasound-guided biopsy confirmed metastatic DFSP-FS. The patient underwent robotic-assisted distal pancreatectomy, achieving clear surgical margins, followed by adjuvant radiotherapy. Despite declining chemotherapy, he remains disease-free as of September 2024. Discussion: DFSP is associated with a characteristic genetic alteration, the COL1A1-PDGFB fusion gene, driving tumor growth. While typical DFSP rarely metastasizes, DFSP-FS shows a higher incidence of distant spread, reported between 8 and 29 %. Pancreatic metastases are exceptionally rare, with fewer than five cases documented. Wide excision with negative margins remains the cornerstone of treatment, with Mohs micrographic surgery providing optimal local control. Advanced cases may benefit from imatinib, radiotherapy, or multidisciplinary surgical approaches, as demonstrated here. Conclusion: This case highlights the unpredictable metastatic behavior of DFSP-FS and display the importance of advanced diagnostic techniques, vigilant follow-up, and multidisciplinary management in achieving favorable outcomes in rare oncologic scenarios. Highlights: