Abstract
In our recent article published in this journal, we evaluated the presence and frequency of lipoblats in spindle cell and pleomorfphic lipomas (SCL/PL). Overall, lipoblasts were found in 66% of PL.
These cases, which mostly occurred in the typical clinical setting of PL, were also molecular genetically tested to exclude MDM2 and CDK4 amplifications, and stained for CD34 and retinoblastoma protein to further validate the diagnosis(1). Recently, we have been contacted by Dr \kosemehmetoglu who presented to us cases of PL that displayed unquestionable atypical mitoses and thus led to erroneous diagnosis of liposarcoma.
After a review of the literature, we have found only 3 monographs briefly mentioning this histologic feature of PL, which may be very confusing and misleading (2-4). The frequency of atypical mitoses in PL is virtually unknown, Because it might represent an important diagnostic pitfall, we again reviewed our histologically, immmunohistochemically, and molecular genetically validated cohort of 25 PL to assess the frequency of atypical mitoses, which are, however, a more widely acknowl-edged feature of PL.
Thus, besides the routine presence of lipoblasts, we would also additionally like to highlight the possibility of encountering atypical mitosis in PL, which may lead to erroneous overdiagnosis of these lesions, especially as atypical lipomatous tumor/well-differentiated liposarcoma.