Evidence of hydroxyurea activity in children with pretreated desmoid-type fibromatosis: A new option in the armamentarium of systemic therapies.

The treatment paradigm in desmoid-type fibromatosis (DF) has changed in recent years from a surgery-based strategy to a multidisciplinary approach that includes systemic therapies. Among various medical therapies, hydroxyurea has been considered of potential interest. This case series summarizes the experience gained at four centers using hydroxyurea in relapsing DF. Hydroxyurea was given orally at an initial dose of 20 mg/kg/day (escalated up to 30 mg/kg/day as necessary, if well tolerated). The response rate was 18.7% major partial remissions, 37.5% considering any amount of shrinkage, 68.7% considering symptom response or signs of tissue response as well. In patients with no progression, the treatment was continued for 9-24 months. The response rate was moderate, but similar to that reported for other medical therapies currently considered as treatment options in this disease. Though further, larger series are needed to confirm as much, hydroxyurea has potential as an effective alternative therapy for DF.

A giant desmoid tumour required full thickness excision of the lower abdominal wall. The resultant massive defect was closed with reconstructive tissue matrix (Strattice). The mesh acted as successful scaffold for regenerative repair enabling skin grafting of a stable granulation bed giving a satisfactory mechanical and cosmetic result. This mesh should be explored further as a simpler alternative to complex plastic reconstructive techniques for large abdominal soft tissue defects.

A 17-year-old male reported swelling of his abdomen and abdominal pain. He was referred to our hospital with no history of surgery, trauma, or familial adenomatous polyposis. A large tumor in the abdominal cavity was detected by computed tomography, and surgical resection was performed. The tumor was thought to have developed from the anterior lobe of the transverse colon mesentery. It weighed 5.9?kg. Tumor cells with collagen fibers were observed in histopathological examination, but heteromorphism and the nuclear fission image were not apparent. Immunostaining revealed beta-catenin expression in the tumor cell nucleus. Diagnosis was an intra-abdominal desmoid tumor. Currently, there are no signs of recurrence. In this case, preoperative diagnosis was difficult, but surgery was the optimal treatment according to the symptoms.

Here we report the case of a 46-year-old patient with a desmoid-type fibromatosis (DF) mimicked a large cystic tumor in the retroperitoneum. Ultrasonography and computed tomography were performed in order to search for localizations and characteristics of the cystic tumor. Radiological findings showed an oval cystic mass with a relatively thick wall, measuring 18.3?×?12.3?×?21.5 cm in the left upper abdomen. Laparoscopic spleen-preserving distal pancreatectomy was performed and histopathological examination by immunohistochemical study enabled us to diagnose a DF invading the pancreatic parenchyma. The patient remained asymptomatic during an 8-month follow up period. DF can manifest as a mainly cystic mass with a thick wall, as in our case, which makes the correct diagnosis difficult. DF should be included in the preoperative differential diagnosis of a cystic retroperitoneal mass, regardless of its rarity.

This study was designed to evaluate the prevalence of CTNNB1 (beta-catenin) mutations in cases of papillary thyroid carcinoma with desmoid-type fibromatosis (PTC-DTF) expressing aberrant nuclear and cytoplasmic immunoreactivity for beta-catenin. Eight cases of PTC-DTF were available for this study. Immunohistochemistry for beta-catenin and BRAFV600E was performed. CTNNB1 and BRAFV600E mutations were also evaluated by direct sequencing. For beta-catenin, although we could demonstrate aberrant nuclear and cytoplasmic immunoreactivity in DTF components in all cases, suggesting activated Wnt signaling, direct sequencing revealed a missense mutation, c.121A>G (p.T41A), in exon 3 in only one case, and no mutations in exons 3, 4, and 5 in the other cases. In the BRAFV600E analyses, immunohistochemistry revealed positive staining in the carcinoma cells but not DTF components of all cases. These findings were subsequently validated by direct sequencing. This study suggests the significance of the BRAFV600E mutation and activation of Wnt signaling pathway in the carcinoma cells and DTF components, respectively. We believe that the CTNNB1 mutations are not the major factor behind beta-catenin translocation indicating Wnt pathway activation. Further study is required to evaluate whether molecular abnormalities other than the CTNNB1 mutation cause activation of Wnt signaling in DTF components of PTC-DTF.

Mesenteric fibromatosis (MF) is a locally aggressive proliferative spindle cell lesion of the mesentery. A 34-year-old male presented with increasing abdominal pain and constipation. On workup, patient was found to have a large pelvic mass on CT A/P concerning for cancer. The patient underwent surgical excision of >15 cm intra-abdominal tumor along with adherent small bowel section. Histology of the tumor showed a spindle cell lesion consistent with MF. Previous reports have shown association of MF with Gardner syndrome and familial adenomatous polyposis. We present the first reported case of MF in a patient with previous neuroblastoma.