Today's News

Thursday, March 19, 1998

Study examines relationship between intraosseous lipoma and unicameral bone cyst in foot

A retrospective review of bone radiology archives at the Armed Forces Institute of Pathology, Washington, D.C., found 31 cases of unicameral bone cyst and nine cases of intraosseous lipoma (two cases were bilateral) in the foot from 1940 to present. The data was presented in poster exhibit A 41 on Thursday.

"We found some interesting relationships between the two foot lesions," said study co-author Theodore J. Choma, MD, orthopaedic surgery service, Walter Reed Army Medical Center, Washington, D.C. "We found they share a similar site in the hindfoot and intraosseous lipoma appears later in life.

"Unicameral bone cysts usually are found in the long bones, and less commonly found in the foot. Even rarer are intraosseous lipomas of the foot," Dr. Choma said. "The purpose of our study was to analyze any similarities in patient profile, location of the lesion or symptoms in these two entities."

"Our most interesting finding was four patients with pathologic fracture had an unicameral bone cyst," Dr. Choma said. "This is a phenomenon not previously reported."

Dr. Choma reported 36 lesions occurred in the same location. "They were centered at the base of the calcaneal neck just inferior to the anterior portion of the posterior facet," he said. All lesions were radiographically lytic with geographic margins, most commonly 1A (83.3 percent); devoid of matrix (88.1 percent); and having an average area of 6.853.6 centimeters.

Pain was the most frequent presenting symptom in 28 cases. "However, intraosseous lipoma was more symptomatic than the unicameral bone cyst," Dr. Choma said.

The mean age of the patients with unicameral bone cyst was 19 years old; the average age of patients with intraosseous lipoma was 36 years old.

The lesions were treated with curettment; 13 lesions had additional bone grafting. There were no recurrences.

Co-authors of the study are Mark D. Murphey, MD, department of radiologic pathology, musculoskeletal radiology division, Armed Forces Institute of Pathology, Washington, D.C.; H. Thomas Temple, MD, department of orthopaedic surgery, University of Virginia Health Science Center, Charlottesville, Va.; Mark S. Mizel, MD, Baltimore, Md.; and Chad A. Haley, BS, Alexandria, Va.

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1998 Academy News Mar.19 Index C

Last modified 02/March/1998