Surgeons who operate on benign soft tissue masses that are presumed to be benign often encounter malignancies that require wider excision, a procedure referred to as an ‘unplanned excision’. These patients then undergo additional excision after being diagnosed with malignancies. We aimed to investigate the outcomes of patients with soft tissue sarcomas who underwent unplanned excisions of their tumors followed by additional excisions at our institution. We examined 6 patients with soft tissue sarcomas, 3 men and 3 women, who underwent additional excisions after an unplanned excision between 2004 and 2015 at our hospital. Their mean age was 59.5 y, their mean primary tumor size was 9.0 cm, and 3 each had superficial and deep tumors, respectively. No residual tumor cells were observed in patient specimens following additional excision. None of the patients required plastic reconstructions. The 5-y survival rate was 100%, while the 5-y local recurrence-free rate was 83% after 1 patient experienced local recurrence and underwent a second additional resection. Our data suggest that patients who undergo unplanned excisions should also undergo additional excisions to avoid tumor recurrence.