Desmoid-type fibromatosis in the setting of malignant peritoneal mesothelioma: a case report of two rare diseases

Desmoid-type fibromatosis (DTF) is a rare benign lesion that usually arises from the abdominal wall or extremities and rarely from the mesentery or intrabdominal organs. Malignant peritoneal mesothelioma is also a rare, yet aggressive disease. To our knowledge, this is the first case report of desmoid-type fibromatosis in the setting of malignant peritoneal mesothelioma. Case presentation: An early 30-year-old female was referred to our center for large intra-abdominal mass concerning for recurrent malignant peritoneal mesothelioma after previous cytoreductive surgery with hyperthermic intraperitoneal chemotherapy and adjuvant chemotherapy. Further investigation revealed a large mesenteric mass, which was resected en bloc with the cecum and terminal ileum. Pathologic findings confirmed a surprising diagnosis of desmoid-type fibromatosis. Conclusions: No adjuvant therapy was offered to this patient due to negative tumor margins; however, close follow-up will be provided for recurrence of both malignant peritoneal mesothelioma and desmoid-type fibromatosis, which can be differentiated in the future via biopsy in this patient.

Mesenteric fibromatosis (desmoid tumor) is a locally aggressive fibroblastic lesion, characterized by a high recurrence rate that makes treatment challenging. Currently, there is no evidence-based treatment approach. We report the case of a female patient with a history of neuroendocrine tumor, who underwent 68Ga-DOTATOC positron-emission tomography/computed tomography (PET/CT), showing increased focal abdominal uptake suggestive of disease relapse. Histological examination revealed typical findings of fibromatosis. These findings indicate the expression of staining for somatostatin receptors (SSTRs) on fibromatosis cell surface and suggest to include fibromatosis among the potential causes of false-positive results at 68Ga PET/CT. Moreover, SSTRs expressed in desmoid tumors could be further investigated as a therapeutic target.

Meckel’s diverticulum (MD) is among the many known congenital malformations of intestine. It is seen in approximately 2% of the population. Desmoid tumors are unusual. They are unique, well-differentiated, and fast-growing musculoaponeurotic fibromatosis tumors, contemplated as Grade 1 fibro sarcoma. They offer exclusive management challenges to surgeons. The most common presentation of desmoid tumors is of painless masses with sluggish growth. Rarely, they may present as intestinal obstruction leading to surgical emergency. We present the only case in history till date along with review of the relevant literature of a 65-year-old gentleman who presented to us with features of intestinal obstruction who successfully underwent elective segmental resection of ileum containing MD with its desmoid tumor. A multimodality approach is needed to tackle such kind of diseases with a team comprising oncosurgeons, oncophysicians, and radiation oncologist to design a standard treatment protocol.

Background: The role of both hormonal contraception and pregnancy on the outcomes of desmoid-type fibromatosis (DF) is debatable. Materials and methods: In the present study, we selected female patients of childbearing age from the prospective ALTITUDES cohort. The primary study endpoint was event-free survival (EFS), with an event defined as relapse or progression. We estimated the risk of events according to the use of hormonal contraception [estrogen-progestin (EP) and progestin] and pregnancy status using multivariate time-dependent models, controlling for major confounders. Results: A total of 242 patients (median age, 34.7 years) were included in the present study. The abdominal wall was the most common tumor site (51%). Patients were managed by active surveillance (80%) or surgery (20%). Pregnancy occurred within 24 months before, at the time of, and after DF diagnosis in 33%, 5%, and 10% of the cases, respectively. Exposure to hormonal contraception was documented within 24 months before, at the time of, and after diagnosis in 44%, 34%, and 39% of the cases, respectively. The 2-year EFS was 75%. After adjusting for DF location, tumor size, front-line treatment strategy, and hormonal contraception, we observed an increased risk of events occurring at 24 months after pregnancy [hazard ratio (HR) = 2.09, P = 0.018]. We observed no statistically significant association between the risk of events and current EP exposure (HR = 1.28, P = 0.65), recent EP exposure (within 1-24 months, HR = 1.38, P = 0.39), current progestin exposure (HR = 0.81, P = 0.66), or recent progestin exposure (HR = 1.05, P = 0.91). Conclusions: In our study, a recent history of pregnancy was associated with an increased risk of progression/relapse in patients with newly diagnosed DF, whereas hormonal contraception did not demonstrate an association with progression/relapse.

Rationale: Desmoid fibromatosis is a rare benign tumor, but due to its rarity and diverse clinical course, treatment guidelines have not been established. However, since a good prognosis can be expected, an accurate diagnosis and appropriate treatment are required. We describe a rare case of desmoid fibromatosis on young female that presented as huge abdominal mass. Patients concerns: A 28-year-old female with left upper abdominal pain 1 month ago was referred. Diagnoses: Abdominal computed tomography and magnetic resonance imaging revealed a heterogeneous soft tissue mass approximately 29 × 17 cm in size in the left abdomen with abdominal wall invasion and pathological fracture in costochondral junction of the left 8th to 10th ribs. Interventions: Surgical resection was performed. Outcomes: 33 × 23 × 6 cm sized tumorous mass showed proliferation of bland fibromatosis and myofibroblast with nuclear ?-catenin expression on pathological examination. Desmoid fibromatosis arising from intra-abdominal soft tissue with ribs and pericardium invasion was diagnosed. Lessons: The mainstay of treatment of symptomatic desmoid fibromatosis is surgical resection, and in the case of abdominal tumor, it can be more dangerous when it invades adjacent organ. We report a case that required additionally multidisciplinary approach for surgery and postoperative treatment of huge abdominal desmoid tumor which infiltrate bone and pericardium beyond abdominal cavity.

Rationale: Desmoid-type fibromatosis is a rare benign mesenchymal neoplasm. Only 8% of desmoid-type fibromatosis develops in the abdominal cavity. The mesentery is seldom affected and gastrointestinal stromal tumors need to be considered in the differential diagnosis, particularly when imaging examination shows a tumor containing gases in the abdominal cavity. Only a few cases of gas-containing mesenteric desmoid-type fibromatosis have been reported in the literature. Patient concerns: A 69-year-old male patient presented with hematochezia and intermittent upper abdominal pain. Diagnosis: Contrast-enhanced computed tomography revealed a 3.9 × 3.6 cm gas-containing mass infiltrating the third portion of the duodenum. The tumor was heterogeneous, with cysts and air bubbles. It showed heterogeneous weak-to-mild enhancement in the solid part. Postoperative pathological examination confirmed a final diagnosis of mesenteric desmoid-type fibromatosis. Interventions: The patient underwent surgical resection of intra-abdominal lesion. Outcomes: No evidence of local recurrence was noted during the 6 months of follow-up. Lessons: Accurate preoperative diagnosis is difficult for an intra-abdominal gas-containing mass on computed tomography scan. The appearance of spiculated infiltrative margin suggests the diagnosis of desmoid-type fibromatosis. Further investigation of imaging evidence and treatment methods is necessary.