Radial nerve entrapment caused by a desmoid tumor :A case report and literature review [Full Article]

We report a case of a 45 year’s old woman with a radial nerve entrapment caused by a desmoid tumor involving the right forearm. This case is outstanding because of the posterior interosseous nerve is entrapped inside the tumor. The marginal excision of the mass while preserving the intratumoral radial nerve was laborious. The radial nerve entrapment caused by a desmoid tumor is very rare and intratumoral radial nerve entrapment is also exceptional. The surgical treatment was challenging and the prognosis is uncertain because of the high rates of recurrence of the desmoid tumor.

This report presents a case of rare right shoulder desmoid type fibromatosis in a 48-year-old male that was missed on an initial workup including EMG/NCS and shoulder MRI, and demonstrates the importance of revisiting the diagnostic process if a former workup has yielded an unclear clinical picture.

Herein, we present a rare case of chest wall desmoid-type fibromatosis (DF) in a 43-year-old female, which was discovered accidentally due to a thoracic wall mass that extended outward from the sternum. Computed tomography scans revealed a subcutaneous soft tissue mass anterior to the sternum, which was considered to be a mesenchymal tumor or an inflammatory lesion. The patient underwent surgical excision of the mass. The mass was completely removed and all margins were negative. According to the pathological results, the patient was finally diagnosed as DF. Postoperative radiotherapy was suggested subsequently, especially considering the locally aggressive and infiltrative nature of the tumor. However, this was rejected by the patient, and biannual re-examination was recommended instead. Despite the absence of postoperative radiotherapy, there was no evidence of local recurrence 2 years later.

The majority of desmoid-type fibromatosis (DTF) tumors harbor a beta-catenin mutation, affecting specific codons in CTNNB1 exon 3. S45F tumors are reported to have a higher chance of recurrence after surgery and more resistance to systemic treatments compared to wild-type (WT) and T41A tumors. The aim of this pilot study was to examine the genome-wide DNA methylation profiles of S45F and T41A mutated DTF, to explain the observed differences in clinical behavior between these DTF subtypes. This study demonstrated that S45F and T41A DTF tumors did not exhibit gross differences in DNA methylation patterns. This implies that distinct DNA methylation profiles are not the sole determinant for the divergent clinical behavior of these different DTF mutant subtypes.

We present the multidisciplinary treatment of 20 patients with resectable desmoid tumors, reconstruction method, and experience in managing recurrences. After institutional board review approval, the clinical course of 20 patients diagnosed with desmoid tumors and treated by the University of Texas Southwestern multidisciplinary team were retrospectively reviewed over an 8-year period to analyze patient characteristics and surgical outcomes. Patient, tumor, treatment, and outcome data were compared between patients who underwent surgical resection with formal reconstruction and patients who underwent resection with primary closure. Twenty patients were included in our study. Of those 11 (55%) underwent reconstruction, whereas 9 (45%) underwent primary closure. Primary closure patients were more likely to have positive marginal status post resection (55.6% versus 9.09%; P = 0.050) and higher rate of recurrence (66.6% versus 0%; P = 0.0012) than patients who underwent reconstruction. No recurrences occurred in the reconstructive group; the reconstructive group had significantly higher rates of desmoids located in the abdominal wall than those who underwent primary closure (72.7% versus 11.1%; P = 0.009). Reconstructive surgery was not found to be a risk factor for recurrence. In fact, primary closure was associated with higher reoccurrence and positive margins. This might suggest that during resection, surgeons are focusing more on primary wound closure versus insuring negative marginal status. Collaboration between reconstructive and oncologic surgeons is necessary in the management and potential treatment of desmoid tumors.

Herein, we report a unique case of an 11-year-old boy who presented with a rapidly growing soft-tissue mass after biopsy of a stable fat-rich lesion present in the calf muscles since infancy, with Magnetic resonance imaging findings suggesting an intramuscular adipocytic tumor. The resection showed gardner fibroma (GF) and desmoid fibromatosis (DF). DF arising from a preexisting GF (the so-called “GF-DF sequence”) is a well-documented phenomenon. Although immunohistochemistry was negative for nuclear beta-catenin expression, a CTTNB1 S45F mutation, which has been associated with aggressive behavior in DF, was identified in both components using a next-generation sequencing-based molecular assay. This is the first time a mutation in CTNNB1 has been identified in GF and the GF-DF sequence, thus expanding our knowledge of the molecular pathogenesis of the GF-DF sequence and highlighting the role of molecular testing in pediatric soft-tissue tumors.