Incidental 18F-Fluciclovine Uptake in a Desmoid Tumor Detected in a Patient Undergoing PET/CT Imaging for Prostate Cancer

A 74-year-old man with biochemical recurrent prostate cancer underwent 18F-fluciclovine PET/CT for restaging to determine subsequent treatment strategy. 18F-fluciclovine PET/CT imaging demonstrated incidental focal heterogeneous increased 18F-fluciclovine uptake corresponding to a soft tissue nodule within the musculature of the left anterior abdominal wall. Subsequent ultrasound-guided biopsy of the lesion revealed histopathology compatible with a desmoid tumor. Consequently, the patient underwent surgical resection with wide local excision of the lesion.

Mesenteric fibromatosis-desmoid tumor of mesentery is a rare benign soft tissue tumor of mesentery. On CT, it mimics gastrointestinal stromal tumor (GIST). A 44-year-old female with small intestinal mass, preoperatively diagnosed radiologically and pathologically as GIST. Mesenteric fibromatosis is a rare tumor often mistaken for GIST. Histopathology and immunohistochemistry is the key as management of both the tumors differs.

Desmoid type fibromatosis is a benign neoplastic process non-encapsulated locally invasive and aggressive, which arises from a proliferation of bland-looking fibroblasts and myofibroblasts. The most frequent location of fibromatosis is extraabdominal (60%), abdominal wall (25%) and intra-abdominal (8-15%), rarely can originate in the viscera (0.73%), such as the pancreas, gastroesophageal junction, diaphragm and appendix. In this article, we report a case of unusual presentation, originated in the cecal appendix. A 41-year-old female patient with acute pelvic pain, admitted to surgical ward with a clinical and ultrasound diagnosis of probably ovarian pedicle tumor. An explorative laparotomy revealed a solid mass of 15 cm in diameter arising from the cecal appendix, with the anatomopathological study corresponding to a desmoid tumor of the cecal appendix. The desmoid tumor can arise from several extra and intra-abdominal locations, the latter being the rarest and most aggressive. Accurate preoperative diagnosis is very difficult and almost always patients enter to surgery with suspected diagnosis of intraabdominal tumor of unknown etiology. The risk factors associated to its appearance are not yet characterized. The complete surgical resection of the tumor -with free surgical margins (R0)- is the treatment of choice; however, the risk of recurrence is high even with optimal tumor removal.

A 65 years old, heathy female patient, presented to our Emergency Medicine Department with severe lower abdominal pain of acute onset, associated with nausea and recurrent vomiting. Abdominal examination upon her admission revealed diffuse peritonitis, with a tender palpable mass on the mid abdomen. Per rectum exam was normal. A contrast enhanced computed tomography (CT) scan showed large space occupying lesion of 10*12 cm at left mid-lower abdomen, penetrating into small bowel loop, with free intra-abdominal air and fluid. On exploratory laparotomy, large amount of purulent fluid was demonstrated, along with a large (about 12 cm diameter) soft tissue tumor attached to several bowel loop with small intestine perforation due to tumor penetration. Resection of the tumor with long segment of small bowel, along with primary anastomosis was completed. Her post-operative period (POD) was uneventful, and she was discharged home on POD 6. Histopathological exam of the specimen with hematoxylin and eosin stain showed Mesenterial tumor of Intraabdominal fibromatosis (desmoid), invading to the wall of small intestine with perforation and peritonitis. Surgical margins of mesenterium are free of tumor. Reactive lymph nodes seen in mesenterium.

We report the case of a 55-year-old man with a surgical history of distal gastrectomy with Roux-en-Y reconstruction performed 3 years prior to the present episode. During the follow-up, a newly developed, rapidly growing intraabdominal mass was detected in the mesentery of the small intestine. Although the patient had been asymptomatic, surgical resection was planned with the suspicion of malignancy, especially lymph node recurrence of the gastric cancer, owing to its rapid growth. Laparotomy showed that the tumor was located in the mesentery of the small intestine near the Roux-en-Y limb, and due to the involvement of the feeding vessels to the Roux-en-Y limb, the anastomotic site was resected en bloc with the tumor, and the whole Roux-en-Y limb was reconstructed. The histopathological finding was compatible with desmoid-type fibromatosis of the mesentery of the small intestine. Here we report our case and discuss the previously reported literature, especially related to gastric cancer.

We report the case of a 55-year-old man with a surgical history of distal gastrectomy with Roux-en-Y reconstruction performed 3 years prior to the present episode. During the follow-up, a newly developed, rapidly growing intraabdominal mass was detected in the mesentery of the small intestine. Although the patient had been asymptomatic, surgical resection was planned with the suspicion of malignancy, especially lymph node recurrence of the gastric cancer, owing to its rapid growth. Laparotomy showed that the tumor was located in the mesentery of the small intestine near the Roux-en-Y limb, and due to the involvement of the feeding vessels to the Roux-en-Y limb, the anastomotic site was resected en bloc with the tumor, and the whole Roux-en-Y limb was reconstructed. The histopathological finding was compatible with desmoid-type fibromatosis of the mesentery of the small intestine. Here we report our case and discuss the previously reported literature, especially related to gastric cancer.