Solitary fibrous tumor arising from stomach: CT findings

Abstract

Solitary fibrous tumors are spindle-cell neoplasms that usually develop in the pleura and peritoneum, and rarely arise in the stomach. To our knowledge, there is only one case reporting a solitary fibrous tumor arising from stomach in the English literature. Here we report the case of a 26-year-old man with a large solitary fibrous tumor arising from the stomach which involved the submucosa and muscular layer and resembled a gastrointestinal stromal tumor in the stomach, based on what was seen during abdominal computed tomography. A solitary fibrous tumor arising from the stomach, although rare, could be considered as a diagnostic possibility for gastric submucosal tumors.

Fig. 1

(A) Endoscopy showed a large submucosal tumor in the gastric body with bleeding from a large central ulceration that contained fluid and residual contrast material from a previous barium study. (B) Endoscopic ultrasound (EUS) also showed a large submucosal mass in the gastric body portion.

Fig. 2

Abdominal computed tomography (CT) demonstrated about 5.5 × 3.2 cm sized, well defined large mass arising from the posterior aspect of the lesser curvature side of the gastric body. (A) The mass showed relative hypoattenuation on the precontrast images. (B) In the portal phase, the mass showed intense heterogeneous enhancement. Ulceration in the luminal side and low attenuation in the central cavity were seen within the mass. (C) In the equilibrium phase, the mass showed prolonged enhancement and the bulk of the tumor was seen in an extragastric location.

Fig. 3

On gross pathology, the specimen was an ovoid, lobulated solid mass, measuring 5.4 × 5.2 × 4 cm, which was attached to the stomach as a portion of the stomach. On sectioning of the specimen, it was a well demarcated and relatively homogeneously yellowish mass involving submucosa and muscular layer.

Fig. 4

Histologic findings by Hematoxylin and Eosin [H-E] stains (A, B) and immunohistochemical findings for CD34 and c-kit. (C, D). (A) Photomicrograph (original magnification, × 100; H-E stain) shows that the patternless proliferation of spindle cells with abundant perivascular and intercellular mature collagen formation. Dilated, thick-walled vessels were common in the lesions. (B) High power photomicrograph (original magnification, × 400; H-E stain) shows that non-atypical, round to spindle-shaped tumor cells have little cytoplasm with indistinct borders and dispersed chromatin within vesicular nuclei. There was rarely mitosis. (C, D) The tumor cells showed strong immunoreactivity characteristic of neoplastic cells for CD34 (immunoperoxidase, × 400) (C) and the tumor was negative for c-kit (× 400) (D).