Sarcoma Removed as a Benign Lump: Unplanned Excision in Oregon

A lump under the skin is one of the most ordinary things a doctor sees. A current set of UK specialist guidelines puts it plainly: "By far the most common soft tissue mass of the limbs and torso seen in primary care is benign lipoma."¹ A lipoma is a benign fatty lump.

A small number of lumps are something else. "Soft tissue sarcomas (STS) are rare tumours arising in mesenchymal tissues and can occur almost anywhere in the body."¹ This article looks at one specific problem: a sarcoma that is treated as a benign lump and cut out before anyone has imaged it or taken a biopsy.

What an "unplanned excision" means

Surgeons who treat sarcoma have a name for this event. A 2025 review in the journal Diagnostics explains that the term "unplanned excision" was used "to explain tumor resection without preoperative diagnostic devices, such as magnetic resonance imaging (MRI), and without the intent to achieve adequate surgical margins (R0 resection)."² In the language the UK guidelines use, an R0 margin is "free of malignancy," while an R1 margin means "microscopic tumour cells present at the inked border of the specimen …"¹

The same review explains how this can happen. It notes that "most general surgeons may only encounter a few cases of STS," but "they may see a lot of small and superficial benign tumors, such as lipomas, epidermal cysts, and schwannomas."² The UK guidelines use the phrase "inadvertent surgery without a preoperative diagnosis of sarcoma" for the same event.¹

The features that guidance says should raise concern

The UK guidelines state that "The most common presentation of a sarcoma is a painless enlarging soft tissue mass."¹ They describe four clinical criteria for referral — "soft tissue mass increasing in size, size >5 cm, deep site or pain" — that were built into earlier NICE guidance.¹ The guidelines are candid about a limit of those criteria: they "failed to discriminate from much more common benign abnormalities, typically lipomas or cysts …"¹

England's National Institute for Health and Care Excellence (NICE) uses growth as the trigger for a scan. For adults, its suspected-cancer guideline says: "Consider an urgent, direct access ultrasound scan to assess for soft tissue sarcoma in adults with an unexplained lump that is increasing in size."³ The next step it describes is to "Consider a suspected cancer pathway referral for adults if they have ultrasound scan findings that are suggestive of soft tissue sarcoma or if ultrasound findings are uncertain and clinical concern persists."³

Size and depth also appear in the surgical literature. The Diagnostics review states that "Clinical features such as larger size (≥5 cm) and rapid growth should raise suspicion for STS," and that tumors smaller than 5 cm "that are adherent to the deep fascia or surrounding structures should be treated with suspicion of STS."² The deep fascia is the tough layer of tissue that covers the muscles. The review summarizes the guidance this way: "Current guidelines suggest that any soft tissue mass that is either deep or larger than 5 cm in size should be investigated prior to excision …"²

Ultrasound has limits. The UK guidelines note that ultrasound "is however highly user dependent, and therefore in the case of diagnostic uncertainty, an MRI of the affected region should be performed."¹

What specialists describe doing before surgery

When a lump is suspicious, the UK guidelines set out a sequence. "A pre-treatment histopathological diagnosis should be made, if possible, by percutaneous core biopsy …," meaning a needle sample examined under a microscope.¹ "Cross-sectional imaging of the primary tumour, usually in the form of magnetic resonance imaging (MRI) is recommended prior to definitive surgery."¹ And "Imaging of the thorax by CT scan for lung metastases should be performed prior to radical treatment."¹ That chest scan is part of staging, which means finding out whether and how far a cancer has spread.

Even the biopsy is planned with the later operation in mind. The guidelines state that it "should be planned in such a way that the biopsy tract can be safely removed at the time of definitive surgery."¹

The guidance does allow one exception. "A planned excision biopsy with minimal or no surgical margins may be the most practical option for small subcutaneous lesions that are indeterminate on imaging (<2 cm diameter), as such lesions usually prove to be benign."¹ Even there, the lesion has been imaged first.

For the sarcoma operation itself, the UK guidelines describe the standard as "an en bloc excision with tumour free margins," which "implies removing the tumour in a single specimen with a rim of normal tissue around it …"¹

Why the harm can come from the operation itself

A delayed diagnosis is about time lost. An unplanned excision can add a different kind of harm. The first operation can leave tumor behind, and the tissue it passed through may then have to be treated as contaminated.

The UK guidelines describe what follows when inadvertent surgery results in "unplanned positive margins" — tumor at the cut edge.¹ The patient "should be fully staged and undergo an MRI of the surgical bed to look for gross residual disease."¹ Gross residual disease means tumor that can still be seen. The guidelines state: "In the absence of any gross residual disease re-excision of the surgical bed may be advised, if adequate margins can be achieved with acceptable morbidity."¹ A re-excision is a second operation. Where further surgery "is likely to result in considerable morbidity or is unlikely to achieve complete clearance of the potentially contaminated surgical bed," the guidelines state that re-excision "may be not appropriate and observation or radiotherapy may be alternative strategies."¹

The research does not settle how much an unplanned excision changes the outcome. On local control — whether the tumor comes back where it started — the UK guidelines note that "Most inadvertent operations are undertaken for cutaneous or subcutaneous sarcomas and further wide excisional surgery plus or minus radiotherapy will usually maintain long-term local control."¹ They add: "There is conflicting data on the prognostic significance of unplanned excisions on local control but there is no doubt that it requires more complex surgery and a greater need for adjuvant radiotherapy in contrast to planned sarcoma operations."¹ The Diagnostics review reports both sides. Patients who received UE "have been reported to have worse clinical outcomes than those who received PE; however, some authors have described that outcomes for patients who received UE are similar to or even better than those of patients who received PE."² Here UE is unplanned excision and PE is planned excision. The review states that the discrepancies are "likely due to differences in characteristics between patients who underwent UE and those who underwent PE."²

What the review does describe is the size of the second operation, the re-excision (RE). "The RE area tends to be more extensive during tumor bed excision than during PE because of the need to resect potential areas of contamination, resulting in the need for more reconstructive procedures (flaps and skin grafts) and wider radiation fields."² A flap moves living tissue from one part of the body to cover a wound in another.

Those consequences — a second, wider operation, possible flaps or grafts, and a greater need for radiotherapy — are what a lawyer would compare against what a planned operation would have required.

How Oregon law frames the question

In Oregon, a physician's care is measured by ORS 677.095(1). It provides that a physician licensed by the Oregon Medical Board "has the duty to use that degree of care, skill and diligence that is used by ordinarily careful physicians in the same or similar circumstances in the community of the physician or a similar community."⁴

The guidance above is medical literature, not Oregon law. In a case involving a sarcoma removed as a "lipoma," the factual questions a lawyer would evaluate include what the records say about the lump's size, depth and growth; whether any imaging was ordered or read before surgery; whether a biopsy was considered; and what additional surgery, reconstruction or radiation followed once the pathology report came back.

Related questions are covered elsewhere on this site: radiology misreads, informed consent, and, where the problem is mainly delay, delayed cancer diagnosis and proving damages.

Time limits

Under ORS 12.110(4), a medical-malpractice action must be commenced "within two years from the date when the injury is first discovered or in the exercise of reasonable care should have been discovered."⁵ In Gaston v. Parsons, 318 Or 247 (1994), the Oregon Supreme Court held that "injury," as used in ORS 12.110(4), "consists of three elements: (1) harm; (2) causation; and (3) tortious conduct."⁶ The court held that the period "begins to run when the plaintiff knows or in the exercise of reasonable care should have known facts which would make a reasonable person aware of a substantial possibility that each of the three elements (harm, causation, and tortious conduct) exists."⁶

There is also an outer limit. ORS 12.110(4) provides that "notwithstanding the provisions of ORS 12.160, every such action shall be commenced within five years from the date of the treatment, omission or operation upon which the action is based …," with an exception for fraud, deceit or misleading representation.⁵ More detail is in our post on Oregon's medical malpractice statute of limitations.

This article is educational

This article describes Oregon law in general terms. It is not legal advice and does not create an attorney-client relationship.

Time limits matter. Most Oregon personal-injury and auto-accident claims must be filed within two years of the injury or accident. Medical malpractice claims must be filed within two years of when you knew or reasonably should have known of the negligence, with an outer limit of five years from the act itself (with a fraud exception). Wrongful death claims must be filed within three years of the date of death. Claims against public bodies (cities, counties, state agencies, public hospitals) require a notice of claim within 180 days. Missing these deadlines typically ends a case.

If you think you may have a claim, call Huegli Law at 971-317-6436 for a free case review. Todd Huegli is licensed in Oregon and consults on cases in Oregon only.

Footnotes

1. Hayes AJ, Nixon IF, Strauss DC, et al. UK guidelines for the management of soft tissue sarcomas. Br J Cancer. 2025;132:11–31. https://pmc.ncbi.nlm.nih.gov/articles/PMC11724041/ ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶ ↩¹⁷ ↩¹⁸ ↩¹⁹ ↩²⁰

2. Nakamura T, Hasegawa M. Unplanned Excision in Soft Tissue Sarcoma: Current Knowledge and Remaining Gaps. Diagnostics (Basel). 2025;15(4):453. https://pmc.ncbi.nlm.nih.gov/articles/PMC11853907/ ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷

3. NICE guideline NG12, Suspected cancer: recognition and referral — Recommendations organised by site of cancer (soft tissue sarcoma in adults, 1.11.4–1.11.5). https://www.nice.org.uk/guidance/ng12/chapter/Recommendations-organised-by-site-of-cancer ↩ ↩²

4. ORS 677.095 — Duty of care. https://www.oregonlegislature.gov/bills_laws/ors/ors677.html ↩

5. ORS 12.110. https://www.oregonlegislature.gov/bills_laws/ors/ors012.html ↩ ↩²

6. Gaston v. Parsons, 318 Or 247, 864 P2d 1319 (1994). https://static.case.law/or/318/cases/0247-01.json ↩ ↩²