The Distinct Pattern of Granulomatous Lobular Mastitis with Erythema Nodosum: More Severe Conditions and Extensive Lesions.

PURPOSE

Granulomatous lobular mastitis (GLM) is a benign inflammatory disease of the mammary gland with unknown etiology. Erythema nodosum (EN) is a rare, extramammary symptom of GLM. The purpose of this article was to investigate the clinical features of EN associated with GLM.

METHODS

We recruited 102 GLM patients diagnosed between December 2018 and December 2021 at Renmin Hospital of Wuhan University. The clinical characteristics and laboratory indices of the EN group ( = 12) and the non-EN group ( = 90) were compared.

RESULTS

The proportion of GLM patients with lesions involving ≥2 quadrants and high peripheral white blood cell count, absolute neutrophil count and neutrophil-to-lymphocyte ratio (NLR) was larger in the EN group than in the non-EN group ( = 0.002, 0.025, 0.014, 0.002, respectively). The duration of EN was longer in GLM patients with EN than in GLM patients without EN ( = 0.005). GLM patients with EN had more abscesses and sinus tracts than those without EN ( = 0.003, 0.038). Lesions involving ≥2 quadrants and the NLR were positively associated with the occurrence of EN ( = 0.304, 0.0302,  = 0.002, 0.002). Receiver operating characteristic curve analysis revealed that the area under the curve of the NLR was 0.770. When NLR > 5.73, the sensitivity and specificity of predicting EN were 66.67% and 87.78%, respectively.

CONCLUSION

Our findings suggest that GLM concomitant with EN suggests the presence of a more severe condition and extensive lesions.