Comparison of retroperitoneal liposarcoma extending into the inguinal canal and inguinoscrotal liposarcoma

Background: This study was designed to analyze differences between retroperitoneal liposarcoma (RLPS) extending into the inguinal canal and inguinoscrotal liposarcoma. Methods: We retrospectively reviewed the records for patients who were managed for inguinal liposarcoma at Samsung Medical Center, a tertiary hospital, between January 1998 and December 2016. Patient data on demographics, tumour location, surgery, adjuvant therapy, histology, recurrence and death were collected. We used Mann–Whitney, Fisher exact and Kaplan–Meier log-rank tests to analyze differences between groups. Results: Seven of 179 (3.9%) patients with abdominal liposarcoma had inguinoscrotal liposarcoma, and 6 of 168 (3.6%) patients with RLPS had extension to the inguinal canal. No differences were observed between groups in sex (p > 0.99), mean age (49.7 ± 6.4 yr v. 52.1 ± 12.5 yr, p = 0.37), laterality (p > 0.99) or scrotal involvement (40.0% v. 66.7%, p = 0.57). The RLPS group had significantly larger tumours than the inguinoscrotal group (27.9 ± 6.8 cm v. 7.8 ± 4.2 cm, p = 0.001). Postoperative complications were significantly more common in the RLPS group (n = 4, 83.3%); patients in the inguinoscrotal group experienced no postoperative complications (p = 0.021). Log-rank tests showed that the groups had no statistical differences in disease-free survival (p = 0.94) or overall survival (p = 0.10). However, inoperable disease-free survival was significantly poorer in the RLPS group (p = 0.010). Conclusion: Although initial signs and symptoms can be similar, RLPS extending into the inguinal canal was associated with significantly higher morbidity and mortality than inguinoscrotal liposarcoma.