Intramuscular Metastasis of Carcinoma

Non-small cell lung cancer with concomitant intramuscular myxoma of the right psoas mimicking intramuscular metastasis: A case report and literature review

“…Although the CT presentation did not conform to the typical skeletal muscle metastasis, which is rather rare, this suspicious diagnosis could not be ruled out solely relying on the imaging findings, particularly considering that NSCLC is prone to distant metastases (7). The differential diagnosis should include intramuscular metastasis and primary soft-tissue tumors, as each can arise from the psoas muscle and cause lumbar pain (13)(14)(15). Furthermore, the definition of the nature of the muscle abnormality would be of great value, as the correct diagnosis would affect the following clinical management and vary the prognosis of the patient.…”

Skeletal muscle metastasis from malignant melanoma: a case report and review of the literature

“…The commonly reported primary malignancies that may metastasize to the skeletal muscle are lung cancer, renal cell carcinoma and gastrointestinal tumours and genital tumours, but rarely melanoma [13][14][15][16][17][18][19][20][21][22] . The best epidemiological evidence for skeletal muscle metastasis reported to date was from an 8-year retrospective review of Surov et al They reported an incidence of 1.2% out of 5,170 patients that presented with metastatic solid malignancies, and most of them (91.8%) already had widespread metastases when the distal skeletal muscle was found to be invaded, hence it's uncommon to see isolated intramuscular metastases without spreading to other distant organs as in our case.…”

“…The common clinical scenario in which skeletal muscle metastasis is detected is the presenting symptom of a painful mass (usually more than 5 cm in diameter) [13][14][15][16][17][18][19][20][21][22] . This may be an important clue to suggest metastasis rather than a primary sarcoma of soft tissue, which is more commonly seen but typically present as painless soft tissue masses [14,20] .…”

“…MRI is still the gold standard for imaging muscle disease and is indispensable in diagnosing soft tissue malignancy. The lesions are usually of low signal intensity on T1 and high signal intensity on T2 weighted images and enhancement with gadolinium [13] . These findings are not pathognomonic for skeletal muscle metastases and differential diagnosis should include sarcoma and abscess [30] .…”

“…Options may include radiotherapy, palliative surgical excision, chemotherapy and sometime interferon-α if patient is fit and able to tolerate the toxicities. Pain due to skeletal muscle metastases can be effectively palliated by radiation therapy using a dose of 40Gy-50Gy [13] . And surgical excision may be helpful in carefully selected patients such as those with painful isolated masses and following a long disease-free interval after appropriate treatment of the primary carcinoma.…”