LAUSR

Rationale: Calcifying fibrous tumors (“CFT”) are recognized as extremely rare mesenchymal tumors with benign biological behavior and low rates of recurrence are seen after removal. The first case of a CFT was reported in 1988 as a possibly inflammatory triggered pseudotumor in deep soft tissue of children. Histologically, the tumor is typically composed of dense hyalinized collagen with paucicellular infiltration of lymphocytes and fibroblasts as well as psammomatous or dystrophic calcifications. It can affect soft tissue in very different anatomical locations, also intrathoracic and intra-abdominal, mimicking various different diagnoses. The etiology is understood to be unclear. Asymptomatic CFTs can be found incidentally on medical images. Patient concerns: We present the case of a calcifying tumorous lesion found incidentally in the mesentery of the terminal ileum of a 34-year-old male patient in February 2016 undergoing a computed tomography for a urinary tract infection. Diagnosis: Histopathological and immunhistochemical examination after surgery revealed a CFT. Interventions: Our patient underwent lower abdominal median laparotomy for tumorectomy. Outcomes: Two years after surgery the patient is free of a recurrence. Lessions: We add another case of intra-abdominal CFT to medical literature to provide more information about this very seldom tumor. While the etiology of CFT should be further investigated, diagnosis and therapy seem clarified. CFT should be kept in mind as a rare differential diagnosis of calcifying tumors also in the abdominal cavity. Immunohistological work-up is important for finding the diagnosis and may also help solving pathogenetical questions.