Woman's Arm Tumor Disappears After Biopsy, Leading to Remission Without Treatment

A 59-year-old woman's rapidly growing arm tumor disappeared after a biopsy, putting her into remission without any treatment, @NewScientist reported. The lump, identified as a myxofibrosarcoma in the connective tissue between her skin and muscle, contained aggressive cancer cells likely to spread.

This marks one of nine known cases where a biopsy led to the disappearance of such a tumor within a few weeks.

The woman noticed the lump a few weeks before seeking medical help, when it measured 2 centimeters wide and was progressing rapidly, causing pain and discomfort. Rohit Sharma at Marshfield Clinic Health System in Wisconsin treated her. Sharma and colleagues marked the tumor's location with tattoo ink and took a biopsy using a thin needle.

The biopsy revealed the aggressive nature of the myxofibrosarcoma. Two weeks later, the woman returned for surgery to remove the tumor, but clinicians discovered it had completely disappeared. After the biopsy, the tumor started to go down within three to four days, Sharma said.

The team surgically excised the tissue surrounding the tumor's former location, and analysis confirmed no cancer cells remained. 'The timing of the biopsy and resolution suggests there’s an immune reaction occurring,' said Rohit Sharma. The woman is now in remission despite receiving no treatment.

'It’s extremely remarkable,' said Toby Lawrence at the Centre for Immunology of Marseille-Luminy in France. 'It really suggests some kind of immune activation in response to the injury of the biopsy, because it had extremely rapid effects on tumour growth,' Lawrence added. The case was published on April 15, 2026, by Gannon M C, Gabor R M, Gupta A, et al.

107111. @NewScientist reported that such spontaneous resolutions after biopsy are highly unusual, particularly for connective tissue cancers. Sharma noted the tumor was likely to spread, emphasizing that cancers kill by spreading.

The woman's concern prompted her to seek help as the lump grew rapidly. An X-ray of the woman’s arm showed the tumor before the biopsy, with an arrow pointing to its location. A subsequent magnetic resonance imaging scan was also part of the documentation.

These imaging details supported the confirmation of the tumor's complete disappearance post-biopsy.