Nodular Mucinosis of the Breast
Differential Diagnosis
A number of low grade or benign lesions are characterized by pools of mucin
| Mucinous DCIS | Extracellular, intralumenal mucin in a duct lined by DCIS, no mucin in contact with stroma |
| DCIS with mucocele-like lesion | Typical DCIS with discrete areas of rupture resulting in mucin pools in stroma, no groups of cells floating in mucin |
| ADH with mucocele-like lesion | Some but not all features required for diagnosis of DCIS with discrete areas of rupture resulting in mucin pools in stroma, no groups of cells floating in mucin |
| Mucocele-like lesion | Pools of mucin in stroma variably lined by bland epithelium, usually no groups of cells floating in mucin (if present they are normal ductal cells and are not complex), almost always a microscopic lesion |
| Mucinous carcinoma | Mucin in contact with stroma, neoplastic cells floating in mucin |
| Nodular mucinosis | Nodules of stromal mucin, no epithelial component, subareolar |
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Fibroadenomas may show myxoid stromal change
- They always have an associated epithelial component
- They are rarely superficial
- Nerve sheath myxoma of the breast (Wee 1989) appears to be the same lesion as nodular mucinosis
- Use of this term requires a positive S100 stain
- Myxoma of the breast (Arihiro 1993) appears to be the same lesion as nodular mucinosis
