Images in pathology. GIST versus inflammatory fibroid polyp

Clinicopathologic features of inflammatory fibroid polyp of the esophagus

AIM: To explore the clinical and pathological features of inflammatory fibroid polyp (IFP) of the esophagus and to discuss its diagnosis, differential diagnosis, treatment and prognosis.

METHODS: A case of IFP of the esophagus was investigated by light microscopy and immunohistochemistry. A literature review was then performed to summarize the clinical and pathological features of the disease.

RESULTS: A 71-year-old man presented with epigastric/retrosternal pain and dysphagia for 3 months. Endoscopy revealed a hemispheric lesion, 2.5 cm in size, in the esophageal mucosa about 35 cm from incisors. On EUS, the lesion (13.2 mm x 11 mm) was hypoechogenic and inhomogeneous, and was located under the mucosa of the esophagus, with a clear boundary. Surgical resection of the esophageal mass was performed, and the final pathologic diagnosis was IFP of the esophagus.

CONCLUSION: IFP of the esophagus is an extremely rare mesenchymal tumor with benign behavior and good prognosis. A correct preoperative diagnosis is difficult and relies on postoperative pathological examination. Surgical excision is the preferred treatment for IFP.

Reactive nodular fibrous pseudotumors of the gastrointestinal tract: report of 8 cases

Eight cases of reactive nodular fibrous pseudotumor of the gastrointestinal tract are presented. The patients included 6 males and 2 females between the ages of 1 and 68 years (mean age 41.5 years). Three tumors involved the small intestine, and 5 of the investigated lesions were located in the large bowel. Of these, 2 originated in the sigmoid colon, 1 in the cecum, 1 in the appendix, and 1 in the large bowel not otherwise specified. The tumors' size varied from 3 to 10 cm in the greatest diameter (mean 6.2 cm). Histologically they were composed of stellate or spindle shaped cells resembling fibroblasts arranged haphazardly or in intersecting fascicles, embedded in a collagen-rich stroma, with sparse intralesional mononuclear cells frequently arranged in lymphoid aggregates. Immunohistochemically, the lesions were positive for vimentin (7/7), smooth muscle actin (8/8), muscle-specific actin (5/7), cytokeratins AE1/AE3 (6/7), and CAM 5.2 (1/7), and antigen CD68 (1/7). No case (0/8) reacted positively with antibody to CD117 (c-kit). Genetically no substitutions, deletions, or insertions occurred in exon 11 in all analyzed samples. Likewise, no deletions or insertions in part of exon 9 were observed. Ultrastructurally the tumor cells revealed features typical of myofibroblasts. According to the morphologic, immunohistochemical, and ultrastructural features mentioned above, especially to the positivity of low-molecular-weight cytokeratins, we propose this lesion to be related to a proliferation of multipotential subserosal cells rather than ordinary myofibroblasts or fibroblasts.

Vanek's tumor (inflammatory fibroid polyp). Report of 18 cases and comparison with three cases of original Vanek's series

Eighteen cases of Vanek's tumors are presented. The patients included nine men and nine women between the ages of 45 and 93 years (mean, 66.2 years). Nine cases were clinically diagnosed as polyps of the gastric antrum, five cases as polyps of the stomach (not otherwise specified), one polyp was located in the ileum and the three remaining polyps in the small intestine (not otherwise specified). The thirteen polyps with available size information measured from 0.4 to 5 cm in the greatest diameter (mean, 2.2 cm). Immunohistochemically, the affections were positive for vimentin (18/18) and CD34 (15/18). All the cases negative for CD34 also lacked concentric onion skin-like formations of the spindle cells around glands and vessels. The different immunophenotype and absence of concentric formations could be explained by the existence of two different lesions commonly designated as Vanek's tumor (inflammatory fibroid polyp) or by the hypothesis of various evolutional stages. In the differential diagnosis, it is important to distinguish namely eosinophilic gastroenteritis, gastrointestinal stromal tumor, inflammatory pseudotumor, hemangioendothelioma, and hemangiopericytoma. In contrast to gastrointestinal stromal tumors, genetically no substitution, deletion, or insertion occurred in c-kit exon 11 in all analyzed samples. Likewise, no deletion or insertion in part of c-kit exon 9 was observed.