Inflammatory myofibroblastic tumor of the appendix

Abstract

Inflammatory myofibroblastic tumor (IMT), also called inflammatory pseudotumor is a rare disease of mesenchymal origin, first described in 1937. Cases of IMT involving the appendix are exceptional, and they can mimic malignant appendicular tumors. Case report: A 25-year-old woman presented to the emergency department with pain in her right lower abdomen for three days. This was associated with increased body temperature and nausea. Other clinical findings included acute abdomen and laboratory analysis with mildly elevated inflammatory markers. No past history of serious illnesses or abdominal surgery. Because of the lack of specific clinical or imaging signs, IMT still offers a great deal of diagnostic challenge. The macroscopic examination of the appendix revealed a surgical specimen of 5.0x2 cm. The tip of the appendix was distended by mucinous material and had signs of acute appendicitis. Histological examination of the specimen stained with hematoxylin and eosin, revealed a mass showing fibroblastic proliferation accompanied by a dense inflammatory infiltrate in the mucosa and a clear widening of the submucosa. A few areas showed myxoid changes with spindle cells, alternating with polyclonal plasma cells and lymphocytes. Immunohistochemical analysis showed positivity for vimentin and partial positivity for CD68, SMA and desmin. Conclusion: Awareness of this type of tumor in the differential diagnosis of appendiceal masses, avoids overtreatment, and highlights the need of long-term follow-up regarding the tendency for local recurrence and small risk of distant metastasis.