Based on PubMed | Can soft tissue sarcoma cause fever, and when should this symptom prompt medical evaluation?

Soft tissue sarcoma rarely causes fever, but it can happen; persistent or unexplained fever together with a new or growing lump should prompt timely medical evaluation, including imaging and, if needed, biopsy. ^[1] Fever in cancer can also be “paraneoplastic,” meaning the tumor triggers body-wide symptoms without infection, and although uncommon in soft tissue sarcoma, case reports and reviews describe fever and other systemic changes in this setting. ^{[2] [3] [4]}

Can sarcoma cause fever?

• Typical symptoms: Most soft tissue sarcomas present as a painless or painful lump that grows over time; constitutional symptoms like fever are considered uncommon. ^[1]
• Paraneoplastic fever: Some tumors release substances that cause fever, inflammation, or blood count changes even without infection; this phenomenon has been reported with mesodermal tumors including soft tissue sarcoma. ^{[2] [3] [4]}
• Associated lab findings: Rarely, sarcomas can drive marked inflammatory responses, such as anemia, high platelets, liver test abnormalities without obstruction, or extreme white blood cell counts via granulocyte colony-stimulating factor (G‑CSF); these changes may improve when the tumor is treated. ^{[3] [5]}

When should fever prompt medical evaluation?

• Immediate/urgent evaluation: Adults should seek care promptly for high fevers (around 103°F/39.4°C or higher), fevers lasting more than 48–72 hours, or fever with red flags like severe headache, confusion, stiff neck, rash, persistent vomiting, or trouble breathing. ^{[6] [7]}
• Fever with a mass: Any persistent fever accompanied by a new, enlarging, or unexplained lump, especially one present longer than four weeks, should be assessed by a clinician, ideally with imaging and appropriate referral. ^[8]
• Cancer-related concern: Persistent, unexplained fevers or night sweats are general warning signs that warrant a medical appointment, particularly if paired with other concerning symptoms or a growing mass. ^[9]

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How doctors evaluate a mass with possible sarcoma

• History and exam: Clinicians will ask when the lump was first noticed, how quickly it’s growing, and whether there is pain or functional limitation. ^[10]
• Imaging first: Magnetic resonance imaging (MRI) is the preferred test for soft tissue masses to define size, location, and relation to nearby structures; ultrasound may help guide a biopsy. ^{[11] [12]}
• Biopsy for diagnosis: A core needle or incisional biopsy ideally after imaging establishes the exact tumor type and grade, guiding treatment. ^{[11] [12]}
• Timeliness matters: Solid limb masses present for more than four weeks warrant diagnostic evaluation; lesions larger than 5 cm or deep to the fascia generally need MRI followed by an incisional/core biopsy and specialist referral. ^[8]

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What to expect if sarcoma is diagnosed

• Treatment options: Management often involves surgery; radiation and/or chemotherapy may be added based on tumor size, type, grade, and location. ^[13]
• Goal of care: When treated with coordinated, multidisciplinary care, outcomes improve, and limb-sparing surgery is often possible for extremity sarcomas. ^[8]

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Practical steps if you have fever and a lump

• Track symptoms: Note the highest temperature, duration of fever, associated symptoms (night sweats, weight loss, pain), and how fast the lump is growing. ^{[7] [9]}
• Seek timely care: Arrange evaluation within days if fever persists beyond 48–72 hours or is high; do not delay if the mass is enlarging or has been present more than four weeks. ^{[6] [8]}
• Ask about imaging and biopsy: It is reasonable to ask your clinician whether MRI and a tissue biopsy are appropriate to rule out sarcoma or other causes. ^{[11] [12]}

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Quick reference: Fever and soft tissue sarcoma

Topic	Key points
How common is fever in soft tissue sarcoma?	Constitutional symptoms like fever are rare compared with a growing lump; most STS present without systemic symptoms. [1]
Can sarcoma cause paraneoplastic fever?	Yes, though uncommon; reports describe fever with anemia, thrombocytosis, liver dysfunction, or G‑CSF–related leukocytosis that improve after tumor treatment. [3] [4] [5]
When to seek care for fever?	High fever (≈103°F/39.4°C or more), fever >48–72 hours, or fever with red flags (confusion, stiff neck, severe headache, rash, persistent vomiting) needs prompt evaluation. [6] [7]
Fever plus a mass	A new or enlarging lump lasting >4 weeks requires diagnostic evaluation (MRI and biopsy as indicated), even if fever is the only systemic symptom. [8] [11] [12]
Initial workup steps	History/physical, MRI of the mass, then core/incisional biopsy guided by imaging; ultrasound may assist biopsy. [11] [12]
Treatment if sarcoma	Surgery is central; radiation or chemotherapy may be used depending on tumor factors; coordinated multidisciplinary care improves outcomes. [13] [8]

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Key takeaways

• Fever is not a typical symptom of soft tissue sarcoma, but paraneoplastic fever can occur in rare cases. ^{[1] [2]}
• High or persistent fever especially with a new or growing lump should prompt medical evaluation, including imaging and possible biopsy. ^{[6] [7] [8]}
• Early, organized assessment improves diagnosis and treatment options. ^{[11] [8]}