Nasopharyngeal nephroblastoma in a 3-month-old Boer goat

A 3-mo-old, female Boer goat was presented because of respiratory difficulties. Tachypnea and inspiratory dyspnea were noted during physical examination. Thoracic radiographs were unremarkable; however, upper airway and nasal passage radiographs revealed a soft tissue mass within the nasal passages. The patient underwent cardiorespiratory arrest and did not respond to resuscitation efforts during endoscopy. A large, pedunculated, semi-firm mass originated from the soft palate and obstructed 90% of the nasopharynx on autopsy. Histologically, the mass was composed of primitive cells that multifocally formed tubules and glomeruloid structures intermingled with areas of fusiform and blastemal cells. The neoplastic cells were positive for cytokeratin (tubular and glomeruloid cells), vimentin (fusiform population and blastemal cells), and Wilms tumor 1 protein (glomeruloid structures) on immunohistochemistry, consistent with a triphasic nephroblastoma. To our knowledge, nasopharyngeal nephroblastoma has not been reported previously in any species.

Angioarchitecture of Tumors Induced by Two Different Cloned Cell Lines Established from a Transplantable Rat Malignant Fibrous Histiocytoma

Angiogenesis, a biologic process whereby endothelial cells divide and migrate to form new blood vessels, is a key step in tumor growth, invasion, and metastasis. In the present study, we investigated the differences in angioarchitecture between two different tumors induced by cloned cell lines (MT-8 and MT-9), derived from a transplantable rat malignant fibrous histiocytoma, by scanning electron microscopy of vascular corrosion casts. During a 3-week observation period after implantation, the growth of MT-8 tumors appeared to be faster than that of MT-9 tumors. Histologically, MT-8 tumors were of the uniformly undifferentiated sarcoma type arranged in characteristic organoid structures, and MT-9 tumors showed a storiform growth pattern. In MT-8 tumors, neovascularization occurred by sprouting at postimplantation (PI) week 1, and the newly formed capillaries gradually became more tortuous. In MT-9 tumors, at PI week 1, the corrosion casts of newly formed capillaries mainly showed a wavy course but no fingerlike outgrowths of capillaries were seen. At PI weeks 2 and 3, the sprouting was seen specifically in MT-9 tumors, forming basketlike structures and glomeruloid structures of capillaries. These results indicate that angiogenesis or angioarchitecture of MT-8 tumors is different from that of MT-9 tumors, depending on the differences in their tumor histology and by the features like absence or presence of basketlike structures and glomeruloid structures of capillaries.

Nephrogenic Rest in a Crl:CD (SD)IGS BR Rat

A nephrogenic rest was found in the kidney of an 11-week-old male Crl:CD (SD)IGS BR rat. Histologically, the rest was within the renal cortical interstitium and consisted of glomeruloid structures (primitive glomeruli) and inconsistently distinct basophilic tubules lined by a single layer of cuboidal to columnar cells and variably bordered by blastemal cells. Nephrogenic rests have not been reported previously in this rat strain.

Adult Extrarenal Wilms Tumor Occurring in the Uterus

Five previous cases of extrarenal Wilms tumor (EWT) occurring in the uterus have been reported. The oldest patient was 22 years. We report a case of uterine EWT occurring in a 42-year-old woman. Histologically, there was typical triphasic differentiation, including epithelial, blastemal, and mesenchymal elements. The important differential diagnosis in this age group, the malignant mixed mullerian tumor, is excluded by the absence of glomeruloid structures and primitive tubules. The exact histogenesis of EWT is unknown but most likely relates to the presence of nephrogenic rests occurring in the female genital tract.