Re: RUIN?

May 13, 2010

I'm very lucky to work with Dr. Roy Pool, one of the premier bone

pathologist in veterinary medicine, here at TAMU and I asked him about

RUIN syndrome. I am attaching his reply. Dr. Pool enjoys receiving

communication about these types diseases/syndromes and encourages

radiographs and patient history. The department of osteopathology and

Dr. Pool's contact info can be found at

http://www.cvm.tamu.edu/vtpb/pro/osteopath.html. Dr. Pool's reply can

be found below.

,

Thanks for your inquiry. Please send the hospital number so I can see

the dog's radiographic images if we have the films in our system.

Every few weeks I receive an inquiry about RUIN and I have attached a

generic reply below. Although I have had several inquiries about this

syndrome, no one has commented on treatment and I have not followed up

on what has been done except for fusion in a couple of cases but there

was no comment regarding a long term outcome. If you learn more, please

share it with me so I can pass it on when asked.

Roy Pool

RUIN: Name given for a group of lesions centered on the attachment of

the intraosseous ligament and membrane joining the ulna are radius of

the dog.

I have been an orthopedic pathologist for more than 40 years with

interests in orthopedic disorders/diseases of small animals and athletic

horses, i.e. surgical lumps and bumps) as well as bone tumors.

The " RUIN " lesion as I understand it is term used to describe a

spectrum of injuries and disorders affecting the bony insertions likely

involving a previously injured interosseous ligament (mostly a

desmitis/desmopathy). A few of the " RUIN " lesions are rare sites of

vascular tumors or metastatic sites for circulation agents of disease (I

have seen Cocci lesions here) or tumor mets as follows:

Joe , my radiology colleague for 25 years at UCD, first called my

attention to lesions of the interosseous ligament and membrane joining

the ulna and radius when we worked together in bone and joint diagnostic

service in the 70's to 90's at UCD. During and since that time I have

become aware of a spectrum of lesions specific to that location that

range from radiographically productive to lytic lesions with the lytic

lesions having a spectrum of changes from those that have a permeative

destructive pattern with an indistinct margin, i.e. a long zone of

transition, to those that have a smoothly contoured sclerotic rim or

soap-bubble appearance, with a short zone of transition.

These radiographic lesions have a histologic counterpart in the more

than a dozen or so biopsy specimens that have been sent to me along with

their radiographic images as follows:

The largest number of lesions from this area are due to tearing of the

bony insertion of the interosseous ligament/interosseous membrane

(traumatic desmitis) and the severity of involvement of the nutrient

blood vessel that enters the ulna within the interosseous attachment.

Those lesions that are due to partial tearing of the ligament will often

develop ethesophytes that in time may some may produce elongated bony

processes while others in which the periosteum is also focally involved

can form a contoured bony structure resembling the shape of a large

capsule.

I have examined several examples of lytic lesions that are permeative

in their radiographic appearance. Most (4) of these have been

hemangiomas arising at the entrance of nutrient vessel. These benign

vascular lesions can produce multiple small cystic areas confined to the

area in the ulna adjacent to the base of the attachment of the

interosseous ligament. In another case the hemangioma that arose in this

area extended distally in the ulnar diaphysis to nearly fill the

medullary cavity. This tumor used osteoclasts to resorb the inner

cortical surface; however, resorption of the inner cortical surface was

so slow that the periosteum was able deposit new layers of cortical bone

at nearly an equal rate so that no pathologic fracture occurred in the

contoured, expanded diaphysis of the distal ulna. Another purely lytic

lesion with indistinct borders was caused by a primary hemangiosarcoma

that apparently arose in this location.

Focal lytic lesions in this same location that also had indistinct

borders were caused in two cases by granulomatous lesions of

coccidioidomycosis while a third lesion in this location caused by

coccidioidomycosis had a mixed destructive and productive pattern and

had a distinct border. The dog in this last case also had multiple

radiographically typical skeletal lesions of coccidioidomycosis.

The last pattern having a lytic area bordered by a sclerotic rim in the

three cases for which I had biopsies were caused by focal areas of

traumatic avulsion of the attachment of the interosseous ligament to the

ulna that resulted in damage to the nutrient artery and its foramen.

Needle biopsies from these lesions contained evidence of chronic

hemorrhage, hemosiderin, shredded dense collagen fibers, bone fragments

and nodules of reactive bone that had developed along the sclerotic rim

seen on radiographic images. I also recall having at least one

metastatic carcinoma that caused a mixed destructive/productive lesion

in this area.

There appears to be a spectrum of pathology that occurs in this area

having several different causes but with trauma most likely being the

most common cause.

J. Sessum, RVT

Texas A & M University

College of Veterinary Medicine

Small Animal Rehabilitation &

Surgery Technician Supervisor

http://vmth.tamu.edu/rehab.shtml

May 13, 2010

,

Thanks for the info! I have sent a couple of histo samples to Dr. Pool in the

past when he was at UCD. The guy is a brilliant bone pathologist. His

description seems to make much more sense than a single diagnosis of ischemic

necrosis. He did not appear to directly mention ischemic necrosis in his

description below unless that is included under the category of traumatic

disruption of local blood supply or infarction associated with tumor or

infection. I would think that based on the info below that prescribing a course

of physical rehab for these lesions based on the radiographic appearance would

not be the best course unless a biopsy has been done to rule out infection,

primary tumor or metastatic lesion. Does anyone else on the list have other