[Primary endometriosis: a differential diagnosis with the umbilical nodular lesions]. / Endometriosis primaria: un diagnóstico diferencial dentro de las lesiones nodulares umbilicales.

The onset of umbilical nodules with no previous abdominal surgeries or known endometriosis in other locations characterizes primary umbilical endometriosis. We present a 43-year-old woman with a painful umbilical nodule for several months. We report this case to emphasize the importance of the differential diagnosis of umbilical nodules, especially in women during the reproductive period.