Review Article
Primary Leiomyosarcoma of Extragnathic Bone
Clinicopathologic Features and Reevaluation of Prognosis
Muyibat A. Adelani, MD; Stephen J. Schultenover, MD; Ginger E. Holt, MD; Justin M. M. Cates, MD, PhD
● Context.—Leiomyosarcoma most commonly involves the formation PubMed search of the English language literature
female genital tract and occasionally arises within the ret- identified 104 authenticated cases of primary leiomyosar-
roperitoneum, abdominal cavity, or the soft tissues of the coma of extragnathic bone. An additional 3 cases are re-
extremity. Presentation as a primary bone tumor is extraor- ported and illustrated herein.
dinarily uncommon, potentially leading to misdiagnosis. Conclusions.—Approximately half of all patients with
The prognosis is traditionally thought to be dismal. How- primary skeletal leiomyosarcoma either presented with
ever, this conclusion is largely based on individual case metastatic disease or developed metastases within 1 year
reports and small series, in some of which the pathologic of diagnosis. The 5-year overall and disease-free survival
diagnosis is not well documented. rates were 59% and 41%, respectively, comparable to that
Objective.—To review the clinicopathologic features of of other skeletal sarcomas. As for other bone and soft tissue
well-established cases of primary skeletal leiomyosarcoma sarcomas, high histologic grade and tumor stage are pre-
and reevaluate the prognostic implications thereof. dictive of poor outcome.
Data Sources.—A National Center for Biotechnology In- (Arch Pathol Lab Med. 2009;133:1448–1456)
L eiomyosarcoma (LMS) is a malignant neoplasm with
histologic, immunophenotypic, and ultrastructural ev-
idence of smooth muscle differentiation. Excluding cuta-
bone. Based on these prior reports, LMS of bone has been
considered to portend a dismal prognosis.6–12 We present
3 cases and review the clinical, radiographic, and patho-
neous LMS, most cases involve the female genital tract or, logic characteristics of this tumor. In addition, the prog-
less commonly, the retroperitoneum, abdominal and pel- nosis of primary LMS of extragnathic bone is reevaluated,
vic cavities, or deep soft tissues of the extremities. Rarely, considering only those reported cases in which the pub-
LMS may present as a primary tumor of bone, where it is lished histomorphologic, immunophenotypic, and/or ul-
hypothesized to arise from intraosseous blood vessels, trastructural data are conclusive of smooth muscle differ-
pluripotent mesenchymal stem cells, or intermediate cel- entiation.
lular forms such as myofibroblasts.1–4 Since the initial re-
port by Evans and Sanerkin5 in 1965, 131 cases of primary MATERIALS AND METHODS
LMS of extragnathic bone have been reported in the En- A computerized search of the surgical pathology files at Van-
glish literature. Because it is so uncommon, however, it is derbilt University Medical Center (Nashville, Tennessee) from
likely that primary LMS of bone is often misdiagnosed as 1999 to 2008 yielded 3 cases of primary LMS of bone, after me-
tastases were excluded. These cases were reviewed and clinical
undifferentiated pleomorphic sarcoma (previously known data were recorded from the patient’s electronic medical record.
as malignant fibrous histiocytoma), fibrosarcoma, fibro- A literature search for primary LMS of extragnathic bone was
blastic osteosarcoma, rhabdomyosarcoma, myofibroblastic conducted using MEDLINE. Key words used for this search were
sarcoma, or other unspecified sarcoma of bone. In con- ‘‘leiomyosarcoma’’ and ‘‘bone.’’ The search was limited to reports
trast, some reported cases of LMS of bone appear to be written in the English language. Cases arising in the craniofacial
better classified as one of these other unusual sarcomas of bones and those determined to be metastases from other primary
sites were excluded. Each case report or series was reviewed for
pertinent clinical, radiographic, and pathologic data. Twenty-sev-
Accepted for publication January 7, 2009. en of the 131 reported cases of primary LMS of extragnathic bone
From the Department of Orthopaedic Surgery, Washington Univer- were excluded because of inadequate illustrational evidence of
sity in St Louis, St Louis, Missouri (Dr Adelani); the Departments of smooth muscle differentiation defined by standard histomorpho-
Pathology, Vanderbilt University Medical Center (Drs Schultenover and logic, immunophenotypic, or ultrastructural criteria.13,14
Cates), and Pathology and Laboratory Medicine, Veteran Affairs Ten-
For purposes of comparison, all tumors were restaged accord-
nessee Valley Healthcare System (Dr Schultenover), Nashville, Tennes-
see; and the Department of Orthopaedic Surgery, Vanderbilt Orthopae-
ing to the 6th edition of the American Joint Committee on Cancer
dic Institute, Vanderbilt University Medical Center, Nashville, Tennes- TNM staging system for bone sarcomas.15 Histologic grades were
see (Dr Holt). recorded using a binary grading system (low or high grade) by
The authors have no relevant financial interest in the products or c