Mesenteric desmoid tumor with diagnostic challenge mimicking a malignant small intestinal tumor: a case report

Introduction and importance: Desmoid tumors are histologically benign fibroblastic neoplasms with locally aggressive behavior and no metastatic potential. Intra-abdominal desmoid tumors often lack specific imaging features, and preoperative tissue diagnosis may be difficult, complicating treatment decision-making.

Case presentation: A 66-year-old man presented with a painless abdominal mass sensation. Contrast-enhanced computed tomography revealed a well-circumscribed intra-abdominal mass measuring approximately 12 × 10 cm, adjacent to the small intestine, with heterogeneous enhancement and internal low-attenuation areas, raising suspicion of a malignant small intestinal tumor, particularly a gastrointestinal stromal tumor. Surgical resection was performed without a preoperative biopsy due to persistent symptoms and diagnostic uncertainty. The tumor was located within the small bowel mesentery and was resected en bloc with the adjacent small intestine. Histopathological examination confirmed a mesenteric desmoid tumor. Familial adenomatous polyposis was absent, and the tumor was considered sporadic.

Clinical discussion: Mesenteric desmoid tumors may cause tumor-related symptoms without bowel obstruction or overt invasion, and their nonspecific imaging characteristics may lead to diagnostic challenges. In such situations, diagnostic uncertainty can directly influence surgical decision-making and treatment strategy.

Conclusion: This case highlights the importance of considering desmoid tumors in the differential diagnosis of intra-abdominal masses and demonstrates how diagnostic uncertainty can influence the treatment strategy.

Introduction: Liposarcomas are rare malignant tumors of adipocytic origin with a high propensity for local recurrence. Although desmoid tumors are benign, they may present with clinical and radiological features similar to those of soft tissue sarcomas, which may complicate the differential diagnosis.

Presentation of case: We present the case of a patient who underwent an initial resection of a retroperitoneal liposarcoma. During routine follow-up, imaging suggested a local recurrence. Following a multidisciplinary discussion, a second surgical intervention was performed, revealing histopathological features consistent with a desmoid tumor rather than a recurrent liposarcoma.

Discussion: This case demonstrates that a lesion initially suspected to be recurrent liposarcoma may actually be a desmoid tumor. It highlights the importance of a thorough multidisciplinary evaluation and histological confirmation prior to planning further treatment, given that management strategies differ significantly between these conditions.

Conclusion: This observation highlights that lesions following abdominal liposarcoma resection do not always represent tumor recurrence, and that biopsy remains essential for accurate diagnosis and optimal management.

Desmoid tumors are rare, locally aggressive neoplasms that can develop in various anatomical locations. Accurate diagnosis requires a high level of suspicion, as these tumors can resemble other soft tissue sarcomas. This case report discusses a 23-year-old male with a symptomatic thigh mass, highlighting the importance of biopsy and immunohistochemical staining to distinguish desmoid tumors from malignant tumors. We also examine genetic predispositions, evolving management strategies, and the potential of novel therapies such as nirogacestat. Due to the high recurrence rate and unpredictable nature of desmoid tumors, long-term monitoring and a multidisciplinary approach are essential for achieving optimal patient outcomes.

Desmoid fibromatosis is a rare, benign but aggressive tumor of mesenchymal origin. Its main characteristic is local infiltration and a high likelihood of recurrence. Desmoid tumors can occur either sporadically or in a familial form (familial adenomatous polyposis (FAP)). Depending on their location, they are classified as superficial or deep, such as masses in the abdominal wall, extra-abdominal, or intra-abdominal tumors. Rarely, they can be found in the axillary area. We describe a case of a 69-year-old female presenting with a mass in her left axilla that was biopsy-proven to be a desmoid tumor.

This review analyzes the evolving therapeutic landscape of desmoid tumors (DTs) through a comprehensive evaluation of clinical trials registered on ClinicalTrials.gov from 1978 to 2025. A total of 62 DT-related studies were identified, including 23 completed interventional trials investigating systemic and locoregional therapies. Most studies focused on treatment efficacy and safety, with increasing interest in targeted therapies such as tyrosine kinase inhibitors, γ-secretase inhibitors, Wnt/β-catenin pathway inhibitors, and mTOR-targeted agents. Among the most promising therapies, nirogacestat, pazopanib, sorafenib, and imatinib demonstrated meaningful clinical activity and favorable progression-free survival outcomes in patients with progressive or unresectable disease. Locoregional approaches, including radiotherapy and cryoablation, also showed beneficial tumor control and symptom relief. Despite the expanding therapeutic armamentarium, only a small proportion of trials reported published results, highlighting a persistent knowledge gap in DT management. The study emphasizes the need for individualized, multidisciplinary treatment strategies and further molecularly driven research to optimize outcomes for patients with desmoid tumors.

Pediatric fibrous and adipocytic soft tissue masses represent a heterogeneous group of lesions with distinct epidemiology, histology, and clinical behavior. Ultrasonography is the first-line imaging modality, offering rapid, cost-effective evaluation with high diagnostic accuracy, without ionizing radiation or sedation. However, imaging findings are often nonspecific, posing diagnostic challenges. This review highlights benign fibrous lesions (fibromatosis colli, infantile myofibroma, fibrous hamartoma of infancy, desmoid-type fibromatosis, Gardner fibroma, plantar fibromatosis, calcifying aponeurotic fibroma, lipofibromatosis) and adipocytic lesions (subcutaneous fat necrosis of the newborn, lipoma, angiolipoma, lipoblastoma) encountered in the pediatric population.