[69] Benign Notochordal Cell Proliferations in the Ferret: An Animal with a High Incidence of Chordoma

EG Demicco, AE Rosenberg, CR Antonescu, JB Kobler, GP Nielsen. Massachusetts General Hospital, Boston, MA; Memorial Sloan-Kettering Cancer Center, New York, NY

Background: Chordoma is an uncommon malignant tumor of the axial skeleton. Chordoma rarely affects other animals except for ferrets, in which it is a well-recognized neoplasm that develops in the tip of the tail. In humans, chordoma is hypothesized to arise from benign notochordal cell tumors (BNCT) that have been identified in the vertebral column of up to 20% of humans, primarily within the sacral and occipital regions. To further understand the relationship between benign notochordal lesions and chordoma and to identify a relevant animal model, we examined the vertebrae of the tails of a group of ferrets.
Design: Tails from 6-8 month old wild-type research ferrets were fixed in formalin, decalcified, and bisected longitudinally. All of the vertebrae were sectioned, processed routinely, and examined histologically for the presence of benign notochordal proliferations (BNP). When identified, the lesional tissue was stained immunohistochemically with keratin.
Results: Thirty-two ferret tails were examined. All of the intervertebral discs contained centrally located nucleus pulposus composed of notochordal cells. The vertebral bodies contained cancellous bone and hematopoietic marrow. Two benign notochordal proliferations (BNP) were identified, one of which was confirmed by a keratin stain. One BNP was located in the shaft of the tail (larger), whereas the other (smaller) arose in the most distal tail vertebrae. Histologically, the larger lesion was associated with thickened bony trabeculae and replaced portions of the marrow. The BNP were composed of sheets of polyhedral cells with eosinophilic or clear vacuolated cytoplasm. There was no discernable myxoid stroma. No mitoses were identified. The lesional cells stained strongly with keratin.
Conclusions: Benign notochordal cell proliferations occur in ferrets, an animal that is recognized to have a relatively high incidence of chordoma. This finding suggests that ferrets may be an appropriate animal model to study the mechanisms driving benign and malignant notochordal proliferations.
Category: Bone & Soft Tissue

Tuesday, March 23, 2010 1:30 PM

Platform Session: Section E, Tuesday Afternoon


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