Is Calcifying Fibrous Pseudotumor a Late Sclerosing Stage of Inflammatory Myofibroblastic Tumor?

Abstract

Calcifying fibrous pseudotumor is a recently described distinctive lesion, characterized by the presence of abundant hyalinized collagen with psammomatous or dystrophic calcifications and a lymphoplasmacytic infiltrate. The cause and pathogenesis are unclear, but a possible relationship with other pseudotumors, like nodular fasciitis or inflammatory myofibroblastic tumor, has been proposed by some authors. However, cases with overlapping histologic features have not been reported. A 17-year-old girl with multiple peritoneal calcifying fibrous pseudotumors and inflammatory myofibroblastic tumors (inflammatory pseudotumors) is described. Some multinodular lesions showed calcifying fibrous pseudotumors next to inflammatory myofibroblastic tumors. Transitional stages between calcifying fibrous pseudotumor and inflammatory myofibroblastic tumor were also present. This case clearly illustrates a histogenetic relationship between calcifying fibrous pseudotumor and inflammatory myofibroblastic tumor, and it suggests that calcifying fibrous pseudotumor is a late sclerosing stage of inflammatory myofibroblastic tumor, at least in some cases.

Calcifying Fibrous Tumor of the Gastrointestinal Tract

“…Immunohistochemically, the spindle cells stain strongly and diffusely for vimentin 7,17 and factor XIIIa ( Figure, D). 7,8,15 Reactivity with other immunostains, including smooth muscle actin, CD68, desmin, and CD34, is variable and often patchy.…”

“…The most commonly involved sites are the stomach [3][4][5][6][7][8][9][10][11][12][13][14][15][16] and small intestine. 3,4,6,14,[17][18][19][20][21][22][23][24][25] Three examples in the large intestine exist 14,17,26 and a single case in the esophagus. 27 Patient age ranges from 5 to 77 years, with a mean of 40.8 years; no sex predilection is evident.…”

“…Multiple lesions were documented in 11 of 43 patients, many of which had concurrent extra-GI involvement, with the most common site being the mesentery. 14,17,19,20,[22][23][24][25] One author reported GI CFTs occurring in siblings. 19 Although most are discovered incidentally, CFTs in the GI tract can present in unique ways.…”

“…[11][12][13] Three patients with small intestinal CFTs and concurrent mesenteric nodules were seen with obstruction. 17,19,24 Two other small intestinal cases presented with intussusception. 20,21 Some simply manifest as abdominal or epigastric pain.…”

“…The collagenous matrix often exhibits a whorled or storiform pattern but may be haphazard or patternless (Figure, A). 3,6,17,21 Bland spindle cells are embedded within the abundant collagen. The spindle cells exhibit ovoid, vesicular nuclei with fine chromatin and inconspicuous nucleoli and abundant eosinophilic to amphophilic cytoplasm.…”