MONDOR DISEASE DURING COVID-19.In our clinical activity during the Covid-19 pandemic we have been able to attend to a large number of cases that in other circumstances would have been strange to find in primary care; one of them, which caught our attention due to its low incidence, was thrombosis of the thoracoepigastric veins, a pathology described by Henri Mondor and which today bears his name.In the present work we describe Mondor's disease produced in our patient after infection by Sars-CoV-2 and proceed to identify other cases of this disease related to Covid-19 published in the medical literature. The main objective of this work has been to present to family physicians a little known and therefore underdiagnosed disease, while pointing out the usefulness of sciences other than medicine, as is the case of mathematics, which can help us to know details of these pathologies of low incidence.