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Leiomyosarcoma (LMS) is an aggressive sarcoma thought to
arise from the smooth muscle
cells lining small blood vessels
it may either occur in the soft tissue (uterus) or in the bone
fewer than 100 case reports of extra-facial leiomyosarcoma of bone
the mean age of presentation is in 5th and 6th decades of life
most frequently occurs in the
metaphysis of long bones
, but can occur in diaphyseal locations.
the most frequent sites of boney presentation are the femur, tibia, ilium, and humerus
LMS of bone in adults
25% recurrence rate and 25% metastasis rate
75% survival at 3 years with treatment
typical duration of symptoms prior to diagnosis is 6 months
pelvic masses can be difficult to appreciate on inspection exam
can be tender or nontender to palpation
masses will be firm
purely osteolytic lesions with
ill-distinct margins, moth-eaten, or permeative pattern of bone destruction.
primarily intra-medullary but may extend into the soft tissues.
indicated for all staging of tumors to evaluate for lung metastasis
help evaluate bone loss of involved extremity or pelvis
chest CT indicated in all patients as part of staging workup to evaluate for metastasis
differentiate from benign soft tissue tumors
evaluate size, depth, and surrounding anatomy
appears dark on T1, similar to muscle tissue
appears heterogeneous on T2 with areas of increased signal intensity
contrast causes diffuse enhancement of signal within the lesion
spindle cell neoplasm
with similar characteristics shared between the osseous and soft tissue forms of this disease
cells arranged into fascicles
along with myofibrils running parallel
presence of actin and vimentin immunoreactivity
all tumors should be staged appropriately prior to treatment initiation
diffuse metastatic disease to the lungs
large pelvic masses with neurovascular involvement that preclude safe resection
variable response to chemotherapy
better survival when chemotherapy combined with surgery than surgery alone
contaminated resection bed
variable response, difficult to predict
early wide resection of the primary lesion and secondary reconstruction
standard of care in localized disease
clean margin is an important goal of surgical resection
Neo-adjuvant or adjuvant chemo/radiotherapy in the treatment of leiomyosarcoma of bone is controversial
if unable to obtain wide margin consider adjuvant radiation
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Qbank (1 Questions)
A 35-year-old female presents to your office after incidental finding of a aggressive looking lytic lesion in her pelvis. She has no pain, is not pregnant, but states she has been losing weight over the last 6 months for an unknown reason. Bone scan shows significant uptake in the area of her pelvis. Immunohistochemistry stains positive for smooth muscle actin. Which of the following slides correlates to your expected findings on histology?
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PREFERRED RESPONSE ▶
Based on the patients history (unexplained weight loss) and bone scan, she has an aggressive lesion in her pelvis. Immunohistochemisty staining for smooth muscle actin suggests a tumor of smooth muscle origin - or a leiomyosarcoma. The prefix - "leio-" designates smooth muscle tumors. The histopathology presented in Figure A shows interlacing bundles of smooth muscle cells with variable uniformity, high nuclear/cytoplasmic ratio, and mitotic figures - consistent with leiomyosarcoma.
The two cited review articles by Berlin et al and Antonescu et al describe the clinical, radiographic, and histology of this disease as described above.
Figure B - Giant cell tumor
Figure C - Myeloma
Figure D - Osteosarcoma
Figure E - hyaline cartilage
Primary leiomyosarcoma of bone. A clinical, radiographic, pathologic-anatomic, and prognostic study of 16 cases.
Berlin O, Angervall L, Kindblom LG, Berlin IC, Stener B.
Skeletal Radiol. 1987;16(5):364-76.
PMID: 3306938 (Link to Pubmed)
Primary leiomyosarcoma of bone: a clinicopathologic, immunohistochemical, and ultrastructural study of 33 patients and a literature review.
Antonescu CR, Erlandson RA, Huvos AG.
Am J Surg Pathol. 1997 Nov;21(11):1281-94.
PMID: 9351566 (Link to Pubmed)
Patrick O'Donnell MD/PhD
Michael Hughes MD
John Badylak MD
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Lytic lesion in distal femur (C2108)
HPI - 3 weeks of pain. Limping.
What is the diagnosis?
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