Ovarian Teratoma in an Intact Female Rottweiler

Patient Information:

Age: 7 years
Gender: Intact Female
Breed: Rottweiler
Species: Canine

History:

Patient presented with increased urination frequency and hematuria. Lateral abdominal radiographs were performed and a large mineralized mass was visualized caudal to the tail of the spleen.

Lateral radiographs showing rounded mineralized mass caudal to spleen.
Photo Credit: Ridge Lake AH

Ultrasonographic Findings:

The left ovary was severely enlarged (7.8x5.0cm) and rounded in shape with a mixed echogenicity with large cystic cavitations and focal areas of mineralization. Vascularity was minimal on Doppler exam. The uterus and right ovary appeared normal. No other areas of metastasis were visualized within the abdomen.

Ultrasound image of large mixed echogenic left ovarian mass with areas of mineralization.

Abdominal Ultrasound Interpretation:

Left Ovarian mass-the findings are severe-DDX: epithelial tumors (cystadenoma vs adenoma vs adenocarcinoma) vs teratoma vs sex chord tumor vs mesenchymal tumor vs metastatic tumor

Recommendations:

Ovariohysterectomy was recommended with histopathology of the left ovarian tumor. 3 view thoracic radiographs had already been performed and were negative for metastasis. Pre-surgical laboratory work was within normal limits.

Surgical findings:

Ovariohysterectomy was performed with successful removal of left ovarian tumor. The tumor was observed to have areas of skin and hair development as well as large cystic areas during sectioning. No other abnormalities were found in the uterus or right ovary.

Mass at time of ovariohysterectomy.
Photo Credit: Ridge Lake AH

Biopsy Results:

Microscopic description: Markedly compressing the surrounding ovarian follicles and stroma is a nonencapsulated, well-demarcated, nodular, and multilocular mass, composed of various types of well-differentiated and haphazardly arranged tissue derived from the ectoderm and mesoderm. Separating large bundles of neuroparenchyma, scattered ganglion cell bodies are moderate amounts of fibroadipose tissue that surround markedly ectatic/cystic hair follicles, which contain abundant lamellar keratin and hair shafts. Surrounding the hair follicles are few lobules of apocrine glands, and coalescing aggregates of lymphocytes, plasma cells, and scattered pigment laden macrophages.

Microscopic findings: Well differentiated teratoma.

Histopathology Image: Hair follicles evident as well as keratin formation.
Photo credit: Antech Diagnostics

Discussion:

Teratomas are uncommon, but have been described most often in the bitch. They are tumors that originate from at least 2 of 3 germinal layers (ectoderm, endoderm and mesoderm) Therefore, a combination of tissues such as hair, skin, nervous tissue, bone, and teeth can be found within the tumors. While they can become quite large, they are most often benign and removal is curative. Malignant tumors can occur uncommonly.

Patient Outcome:

The patient recovered uneventfully from surgery and continues to do well. Prognosis is excellent in this case.

Sonographer: Kara Woody, DVM

Thank you to Ridge Lake Animal Hospital for collaborating with us on this interesting case and Antech Diagnostics for the histopathology images and report.