Delayed diagnosis is associated with changes in the clinical and ultrasound features of subcutaneous endometriosis near cesarean section scars.

Introduction: The aim of the present study was to highlight the sonographic and clinical characteristics of large (≥30 mm in diameter) scar endometriomas near Pfannenstiel incisions, assuming that large size is a marker of delayed diagnosis.

Methods: We compared clinical, ultrasound (US) and color Doppler findings in 13 patients (mean age 31.3 years) with 13 large scar endometriomas (L-SEs) (mean lesion diameter 41.8 mm; range 30-60 mm) and 17 women (mean age 30.7 years) with 19 small scar endometriomas (S-SEs) (mean lesion size 18.3 mm; range 7-26 mm).

Results: Compared with the S-SE group, the L-SE group had a significantly longer mean interval between the last cesarean section and hospital admission (5.5 vs. 3.3 years; p < 0.01) and longer mean duration of symptoms before admission (43 vs. 17.4 months; p < 0.01). The L-SE group also had a significantly higher percentage of patients who had undergone at least one inconclusive diagnostic examination (Computed Tomography, Magnetic Resonance Imaging, fine needle biopsy, or laparoscopy) (39% vs. 0%; p < 0.05). As for US findings, L-SEs more frequently displayed cystic regions and fistulous tracts (p < 0.05), loss of round/oval shape (p < 0.05), and increased vascularity (p < 0.05).

Conclusions: Delayed diagnosis of scar endometrioma reflected by a longer and more complex medical history results in larger than usual endometriomas with peculiar US findings, which are even more likely to be misinterpreted by physicians and radiologists.