Spontaneous Metastatic Angiosarcoma of the Tongue in a Wistar Rat

Abstract

A primary angiosarcoma was found in the tongue of a six-week-old female Wistar rat, sacrificed for humane reasons during the course of a four-week toxicology study. At necropsy, a nodule protruding from the dorsal part of the tongue was found. The nodule displayed microscopically, irregularly shaped vascular spaces separated by collagenous stroma. The spindle-shaped endothelial cells showed pleomorphism, hyperchromatism, and low mitotic activity; large nuclei with one or more nucleoli were present. Multiple metastases were found in the lungs, and the morphology of the cells resembled that of the primary tumor. Immunohistochemically, the primary tumor and the lung metastases were positive for von Willebrand factor and vimentin. The diagnosis of tongue angiosarcoma metastasizing to the lungs was made on the basis of microscopic and immunohistochemical findings.

Spontaneous hemangiosarcoma in the spleen and liver of a young rat

“…The morphological features of these case reports, including this case, reflect the unique characteristics of hemangiosarcoma in young SD rats: extremely undifferentiated histological images without formation of clear vascular structures. In other cases of a young Wister rat 7 and older SD rats 6 , comparatively mature blood vessels were observed, which supports this hypothesis.…”

“…In addition, it has been reported that spontaneous hemangiosarcoma is commonly found in rats aged 91 weeks or older 6 . Only a few cases have been reported in young rats [7][8][9] . In this report, we elucidate the occurrence of spontaneous hemangiosarcoma in the spleen and liver of young rats and describe the histological, immunohistological, and ultrastructural features of this tumor.…”

Metastatic hemangiosarcoma of the liver in a young rat

“…Spontaneous hemangiosarcoma is a rare tumor, and its incidence in Sprague-Dawley rats is reported to range from 0.3% (female) to 0.4% (male) 7 . There are only a few case reports 8 , 9 on young rats. Although the spleen is reported to be the most frequent site of the primary lesion in rats 7 , the tongue 8 , pancreas 10 , lung 11 , and mesenteric lymph node 12 have also been reported as sites of primary lesions.…”

“…Although the spleen is reported to be the most frequent site of the primary lesion in rats 7 , the tongue 8 , pancreas 10 , lung 11 , and mesenteric lymph node 12 have also been reported as sites of primary lesions. Metastasis is often present 1 , and cases of distant metastasis have also been reported 8 , 9 . In this paper, we report a spontaneous case of metastatic hemangiosarcoma in a young rat and describe histopathological and immunohistochemical features of the tumor.…”