Both duct widening and duct ectasia syndrome are frequently bilateral, hence systemic causes are likely involved. Diagnosis
Noninvasive methods to determine duct diameter in live patients are available only recently and it is not clear how the results should be compared with older results from biopsies. Histologically, dilation of the large duct is prominent. Duct widening with associated periductal fibrosis is frequently included in the wastebasket definition of fibrocystic disease. In plasma cell rich lesions diagnosed on core biopsies, steroid-responsive IgG4-related mastitis can be identified by IgG/IgG4 immunostaining. Duct Ectasia Syndrome
The term duct ectasia syndrome has been used to describe symptoms of nonpuerperal mastitis, possibly associated with nipple inversion and nipple discharge. In some contexts, it was used to describe a particular form of nonpuerperal mastitis coincident with fibrocystic disease, frequently involving pasty (coloured) nipple discharge, nipple retraction, retroareolar abscess and blue dome cysts. Abscessation is not very frequent but by some definitions recurrent subareolar abscess is merely a variant of duct ectasia syndrome - abscessation would be obviously more frequent with this definition. Duct ectasia syndrome has been associated with histopathological findings that are distinct from a simple duct widening. In addition to nonspecific duct widening the myoepithelial cell layer is atrophic, missing or replaced by fibrous tissue. The original cuboidal epithelial layer may be also severely impaired or missing. Characteristic calcifications are often visible on mammographic images. Periductal mastitis, comedo mastitis, secretory disease of the breast, plasma cell mastitis and mastitis obliterans are sometimes considered special cases or synonyms of duct ectasia syndrome.
The study also evaluated 9 patients (aged 12–31 years, median age 16) treated with methotrexate + vinblastine, methotrexate + vinorelbine, or vinblastine + vinorelbine; 2 patients attained complete responses, 3 attained partial responses, 2 had steady disease, and 2 had progressive disease; this groups progression-free time was not reached while its overall survival time was 83.4 months. The study concluded that the Adriamycin-based and methotrexate/vinblastine/vinorelbine regimens have a high degree of activity in IMT. Due to the low numbers of patients evaluated, no conclusions could be made on which regimen(s) were most effective.In addition to the report that compared the effect of ALK-inhibitors to other therapy regimens detailed in the previous paragraph, several reports have focused primarily on small numbers of IMT patients treated with an ALK inhibitor. The European Organisation for Research and Treatment of Cancer evaluated the effect of the ALK-inhibitor, crizotinib, on 12 ALK-positive IMT adults who had persistent and/or metastatic disease following surgical and/or drug treatment: 2 patients had complete responses, 4 had partial responses, 5 had steady disease, and none had progressive disease; 9 of these patients had at least 1 year of progression-free survival but one patient died of the disease.