Disclosures: Rahul H. Koya, DO: No financial relationships or conflicts of interest
Case Description: The patient reported decreased left shoulder active range of motion following motor vehicle accident in 10/2019. Left shoulder x-ray revealed Hill-Sachs deformity of the posterior head of the humerus. Magnetic resonance imaging of the left shoulder without contrast showed significant edema involving the deltoid muscle with no signs of septic arthritis. interventional radiology-guided left lung biopsy demonstrated poorly differentiated adenocarcinoma. Subsequent left deltoid biopsy was done, which confirmed metastatic poorly differentiated adenocarcinoma from primary lung tumor. Patient was discharged with oncology follow-up.
Setting: Inpatient Internal Medicine Floor
Patient: 61 year-old male with known history of lung adenocarcinoma presents with acute on chronic left shoulder pain ever since motor vehicle accident in 10/2019. Assessment/
Results: Patient referred to radiation oncology for palliative radiotherapy to relieve shoulder pain, with plan to start chemotherapy with pembrolizumab following completion of radiation. Patient received acetaminophen-codeine 300-30 mg by mouth every 6 hours as needed for pain.
Discussion: Lung cancer is known to metastasize to most organs, including brain, bone, liver, adrenal glands, and lymph nodes. Metastatic spread of lung cancer to skeletal muscle, however, is an extremely rare finding seen in less than 1% of all cases. Skeletal muscle metastases most commonly arise from primary tumors of the gastrointestinal and genitourinary tracts, with the muscles most frequently affected being the thigh, iliopsoas, and paraspinous muscles. To our knowledge, this is the first case of lung adenocarcinoma metastasizing to the deltoid muscle.
Conclusion: Although rare, given the proper conditions, such as blunt trauma, lung adenocarcinoma can metastasize to skeletal muscle.
Level of Evidence: Level V
To cite this abstract in AMA style:
Koya RH, Mora LM, Novikov A, Saliaj M. Rare Metastasis of Stage IV Lung Adenocarcinoma to the Deltoid Muscle with Subsequent Hill-Sachs Deformity: A Case Report [abstract]. PM R. 2020; 12(S1)(suppl 1). https://pmrjabstracts.org/abstract/rare-metastasis-of-stage-iv-lung-adenocarcinoma-to-the-deltoid-muscle-with-subsequent-hill-sachs-deformity-a-case-report/. Accessed May 31, 2025.« Back to AAPM&R Annual Assembly 2020
PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/rare-metastasis-of-stage-iv-lung-adenocarcinoma-to-the-deltoid-muscle-with-subsequent-hill-sachs-deformity-a-case-report/