Detection of skeletal muscle metastases on initial staging of lung cancer: a retrospective case series.
OBJECTIVE
Estimation of skeletal muscle metastases (SMMs) at the time of diagnosis and/or initial staging of lung cancer.


METHODS
Retrospective evaluation of clinical charts and imaging data suggestive of SMMs of patients with histology-proved lung cancer over a 5-year period.


RESULTS
SMMs were identified in 46 out of 1,754 patients. Single and multiple (62.9% of cases) SMMs were detected by total body multi-detector computed tomography (MDCT). They were associated with poorly differentiated (43%) and advanced adenocarcinomas (52%) without clinically relevant symptoms and/or signs. Psoas and buttock muscles were most frequently involved (33.3%). MDCT findings consisted of well-defined homogeneously hyperdense oval masses (31%), lesions with ring-like enhancement and central hypoattenuation (68%), or large abscess-like necrotic lesions (24%). Sonography revealed well-defined hypoechoic masses (41.6%), ill-defined hypoechoic lesions (33.3%), or anechoic areas with a necrotic centre (25%). Positron emission tomography revealed that all SMMs were metabolically active.


CONCLUSIONS
SMMs are uncommon but not negligible in lung cancer, with an estimated prevalence of 2.62% in our series. Although histology remains the recommended method, use of high-performance imaging techniques and increased clinical suspicion may improve their early detection. Efforts addressing their effect on the natural history of lung cancer are needed.
Respiratory Medicine Section, Department of Clinical Medicine and Surgery, "Federico II" University of Naples, Naples, Italy, marialuisa.bocchino@unina.it.
Marialuisa
M
Bocchino
Tullio
T
Valente
Francesco
F
Somma
Ilaria
I
de Rosa
Marco
M
Bifulco
Gaetano
G
Rea
D000230:Adenocarcinoma / Q000175:diagnosis* / Q000473:pathology / Q000556:secondary; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D003952:Diagnostic Imaging / Q000379:methods*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008175:Lung Neoplasms / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods; D019042:Muscle Neoplasms / Q000175:diagnosis* / Q000556:secondary*; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging; D049268:Positron-Emission Tomography / Q000379:methods; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018616:Ultrasonography, Doppler, Duplex / Q000379:methods
D003287:Contrast Media; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18