A comparative study of esophageal stromal tumors and smooth muscle tumors.

OBJECTIVE

To explore the clinicopathological, immunohistochemical, and molecular biologic characteristics of esophageal stromal tumors and smooth muscle tumors.

METHODS

Twenty four cases of esophageal mesenchymal tumors were reclassified by a panel of antibodies such as CD117, CD34 etc. The sequence of 11 exon of c-kit gene were detected in some cases.

RESULTS

There were 3 cases of esophageal stromal tumors, 20 leiomyomas, and 1 leiomyosarcoma. The 3 esophageal stromal tumors occurred in 3 men aged 71, 56 and 60 years respectively. The tumors originated from muscularis propria with the size of 4 cm, 8 cm and 14 cm in diameter. Microscopically, the tumor cells were spindle and epithelioid shaped with slightly basophilic appearance, arranged in intersecting fascicles, diffusing and palisading patterns. Immunohistochemically, the tumors were positive for CD117 and CD34. The mutation of 11 exon of c-kit gene was detected in one case. In comparison, esophageal leiomyomas occurred in a younger population. The age ranged from 30 to 60 years (mean age 41.6 years), 12 male cases, 8 female cases. 15 cases of esophageal leiomyomas were intramural tumors with a diameter of 0.8 - 10.5 cm (mean 4.5 cm) originating from muscularis propria and 5 cases which were intraluminal polyps with a diameter of 0.2 - 1.0 cm originating from muscularis mucosae. Leiomyomas were strongly eosinophilic in appearance, diffuse positivity for alpha-SMA, MSA, and desmin, and no c-kit gene mutation. One male case of leiomyosarcoma had a diameter of 5 cm and originated from muscularis mucosae and displayed a sausage-shaped polyp.

CONCLUSIONS

Leiomyoma is still the most common mesenchymal tumor of the esophagus, the stromal tumor can be similar to gastrointestinal stromal tumors. Typical esophageal leiomyosarcoma is very rare and has different clinicopathologic and molecular biologic features.