An association of peripheral nerve sheath tumors and lipomas

Background: We noticed the coexistence of peripheral nerve sheath tumors (PNST) with lipomas within a subgroup of our patients. Given the prevalence of lipomas in the general population, we sought to investigate the extent of coexistence of the two entities aiming at uncovering any plausible association between both. Methods: A retrospective review of all peripheral nerve sheath tumors (sporadic and syndromic forms) treated by a single surgeon between January 2009 and August 2015 was done. We recorded demographics (i.e., gender, age at diagnosis, imaging information, time to diagnosis) in addition to the method of diagnosis, subtype, number and location of lipomas, if present. Results: Over 6 years, 309 patients with PNST were operated/evaluated. These included 141 sporadic (schwannomas, neurofibromas) and 168 syndromic (neurofibromatosis type 1 and 2 and schwannomatosis). We found 32 patients [10.3%, 95% confidence interval (CI) = 7.43%–14.3%] with coexistent lipomas, some of whom also had a family member with lipoma (n = 3). Of these 26 had schwannomas, 3 had neurofibromas and 3 lacked definitive PNST histopathological diagnosis. Fourteen percent of patients with schwannomas and 2.9% of patients with neurofibromas had coexisting lipomas. Conclusion: We believe there is an increased association of peripheral nerve tumors and lipomas overall.