Atypical Lipomatous Tumors/Well-differentiated Liposarcomas: Clinical Outcome of 67 Patients

Abstract

Atypical lipomatous tumors/well-differentiated liposarcomas are low-grade malignant mesenchymal neoplasms with high propensity to local recurrence and potential to dedifferentiate to higher grades over time. However, the published risks of local recurrence and dedifferentiation vary, and no unified treatment and follow-up plan has been accepted. We performed a study to evaluate the long-term clinical behavior and proper treatment and follow-up strategy for these tumors. We retrospectively reviewed the files of 101 patients treated between 1990 and 2008 with the diagnosis of atypical lipomatous tumors/well-differentiated liposarcomas. For 67 of these patients, complete data and 2-year minimum follow-up were available and were included in the study; 47 patients (group A) had primary surgical treatment at our institution and 20 patients (group B) were referred after ≥1 local recurrences. Mean follow-up was 81 months (range, 24-229 months). The local recurrence rate of primary atypical lipomatous tumors/well-differentiated liposarcomas was 10.6% (5/47 group A patients). The local re-recurrence rate of the recurrent atypical lipomatous tumors/well-differentiated liposarcomas was 52% (13/67 group A and B patients). Recurrences developed as late as 140 months after diagnosis and treatment. The rate of dedifferentiation at recurrences was 4% (1/25 group A and B patients with recurrent tumors). No patients developed metastases. Atypical lipomatous tumors/well-differentiated liposarcomas are associated with an increased rate of local re-recurrence and low risk of dedifferentiation at recurrences. Long-term follow-up is recommended for early diagnosis and treatment of local recurrences.

Primary Extremity Liposarcoma

“…In contrast to the prior study by Jelinek et al, 15 in which 11 of 12 cases of ALT were unencapsulated, all cases of ALT in our study (10/10) contained a tumor capsule radiologically. In keeping with multiple prior case series, 16,17 we saw no metastases in patients with ALT.…”

Clinical outcome of deep-seated atypical lipomatous tumor of the extremities with median-term follow-up study

“…In past literatures, these recurrences have been reported to be between 40 and 67%. 3,5,6,9,13,18 In this current study, 2 out of 3 cases (67%) that underwent reoperation after recurrence demonstrated multiple recurrences, both of which were operated with marginal resection. Thus, preference for reoperation for recurrence is given to wide resection; however, because reoperation often reveals strong adhesion and makes contact with important nerves and vessels, the demerits of wide resection should also be considered.…”

“…Those who recommend marginal resections have suggested the limitations of their research in terms of their short follow-up periods, and also note that recurrence rates can increase as the follow-up period is increased in duration. 8,9 Rozental et al 6 and Macrogenesis et al 18 both report the necessity of at least 5 or 6 years follow-up, and we set the general median-term follow-up of 5 or more years as a cutoff point of our observation period. Among studies describing the clinical outcome of ALT in the extremities, our study has the longest minimum follow-up period.…”

Pleomorphic liposarcoma of the chest wall: A case report

“…Some studies report complete excision of well-differentiated liposarcomas and atypical lipomatous tumors due to high risk of local recurrence. [10] Higher-grade liposarcoma in the retroperitoneum, where wide surgical excision is difficult to achieve, may receive adjuvant radiation therapy. All subtypes of liposarcoma will benefit from complete resection to minimize recurrence.…”