OP13.03: Assessment of palpable nodules of the abdominal wall with postpartum onset

To define the role of ultrasound (US) and magnetic resonance imaging (MRI) in the assessment of palpable nodules with postpartum onset. A series of 17 palpable lesion of the anterior abdominal wall with onset during the 12 months after delivery (12 vaginal, 5 Cesarean) were excised. The pathological diagnosis was desmoid tumor in 7 cases, endometriosis in 7, suture granuloma in 2 and Merkel carcinoma in one. Before surgery, all cases where investigated by US and 12 also underwent MRI. In the 7 desmoid tumors, US showed solid nodules, less echogenic than adjacent fibromuscular structures, with margins clearly identified on a transverse plane, but irregular along the longitudinal plane, highly vascular at color Doppler. MRI documented homogeneous hypointense signals in all sequences due to the presence of fibrous tissue. In the 7 cases of endometriosis, US revealed a dyshomogeneous structure with fluid areas and variable vascularity; MRI demonstrated the presence of hemoglobin degradation products. The 2 granulomas presented as dyshomogeneous and poorly vascularized hypoechogenic nodules, showing small hyperechogenic spots internally. In the single case of Merkel carcinoma, US showed its subcutaneous localisation, excluding any relationship with the muscles. During the postpartum period, the US finding of a solid homogeneous vascular lesion in the context of the muscle fibres of the abdominal wall, is suggestive of a desmoid tumor. Dyshomogeneous lesions with fluid areas and variably hypo- or hyper-vascular can suggest endometriosis on US. MRI allows the identification of hemoglobin degradation products within these lesions.