Presentation
Lower abdominal pain of 4 days' duration, more severe on right, with signs of localized peritoneal irritation - appendicitis +/- perforation?
Patient Data
Subcecal appendix of normal width, containing several gas bubbles.
Elongated, craniocaudally oriented soft tissue mass in center of abdomen, most of it immediately right of midline, measuring ~10 cm in length, having maximum width of 3.2 cm at its center, insinuating between ileal loops and mesenteric vessels. Its widest portion shows lobulated borders, with appearance of cluster of rounded nodules. The mass's slender inferior portion borders on the terminal ileum. Mild fat stranding surrounds the bottom 2/3 of the mass.
No enlarged intra-abdominal, pelvic or inguinal lymph nodes.
Lumbosacral transitional vertebra - lumbarization of S1.
Impression:
The differential diagnosis for the the mesenteric mass includes, but is not restricted to, inflammatory myofibroblastic tumor and solitary fibrous tumor, with desmoid tumor of the mesentery a less likely candidate. Recommend excision, to the extent possible, for a definite diagnosis by histopathology.
At laparoscopy, the lesion had the appearance of clusters of small round nodules embedded in the ileal mesentery, separated by a thin "neck" of twisting vessels.
Case Discussion
Pathology report:
Mesentery of terminal ileum:
All slides show a lobulated and nodular mass that is unencapsulated and shows a hypocellular spindle cell proliferation embedded in dense collagenous stroma. The collagen is arranged in whorls and spindle cells are bland. There are scattered calcifications, many of which are psammomatous. There is abundant surrounding reactive tissue composed of myofibroblasts, chronic inflammatory infiltrate, blood vessels and myxoid stroma. Part of the lesion seems to have undergone torsion with thrombosed and congested blood vessels.
Immunostains show:
CD45 - positive in lymphocytes; c-Kit - positive in scattered mast cells; calretinin - positive in mesothelium; AE1/AE3, pankeratin - positive in mesothelium and myofibroblasts; desmin - focally positive in scattered cells; OCT3/4, HCG, CK5/6, CD99, S100, actin, EMA, CD31, CD34, CD68, HMB45, NSE, synaptophysin, chromogranin, WT1, GFAP, B-catenin, PLAP, S10, ALK, IgG4, caldesmon, DOG1, MUC4 - negative.
Conclusion:
The histological features and stains are consistent with a benign lesion and most compatible with calcifying fibrous tumor 1,2.
Calcifying fibrous tumor is a very rare lesion that has been reported in many locations throughout the body. It is usually asymptomatic and is therefore usually discovered incidentally at imaging. In this particular case of calcifying tumor of the mesentery 3, it was perhaps the vascular torsion seen at laparoscopy and on histopathology that elicited the abdominal pain.
Laparoscopy photo courtesy of Dr. Arie Pelta.
Unable to process the form. Check for errors and try again.