Inflammatory Breast Lesions Flashcards
Mammary ductal ectasia
Dilated, thick-walled ducts filled with pasty, lipid-rich, yellow-brown secretions and foamy histiocytes in the duct lumen and walls. Variably fibrotic intervening stroma with prominent plasmacytic inflammation. Granulomatous and/or xanthogranulomatous features.
In late stages, ducts may be compressed or obliterated by periductal and duct lumenal fibrosis.
Primarily found in peri- and post-menopausal women. Strongly associated with smoking. Presents with pain, nipple discharge, nipple retraction, and sometimes a palpable mass.
Mammography shows ductal patterns of calcification that may mimic DCIS.
Starts in large subareolar ducts, but progresses to involve more proximal tissue.
Lymphocytic mastopathy
Histologic features of keloidal fibrosis, epithelioid myofibroblasts, and periductal/perilobular/perivascular B cell-predominant lymphoid infiltrate. In this image, note the prominent, plump epithelioid myofibroblasts in the stroma.
Primarily occurs in young-to-middle aged women, most commonly women with T1DM. May present as a single or multiple palpable masses, may be bilateral.
DDx for granulomatous lesions of the breast
Idiopathic granulomatous mastitis
Histologic features of lobulocentric granulomas, often with neutrophils, microabscesses.
Usually presents as a mass in young parous women, often related to recent pregnancy
Corticosteroid responsive, but first rule out infection.
Cystic Neutrophilic
Granulomatous Mastitis
Histologically characterized by lobulocentric granulomas, often with
neutrophils or areas of microabscess
formation. Empty (cystic) spaces of dissolved lipid (sometimes containing Faint rod-like structures) surrounded by neutrophils distinguish CNGM from IGM. Giant cells may also be present.
On Gram stain, these bacterial rods are more easily identified as gram positive rods consistent with Corynebacteria, usually C. kroppenstedtii.
Presents as mastitis in parous or
lactating women. Patients often febrile with leukocytosis. Nipple inversion or retraction common; fistulas can occur.
Treatment is not yet established – new entity.
Squamous metaplasia of lactiferous ducts (SMOLD)
Defined as squamous epithelium normally extending into nipple duct orifices for 1-2mm.
If epithelium extends more deeply,
keratin may accumulate, fill and obstruct duct (similar to epidermal
inclusion cyst). Duct rupture results in extrusion of keratin and inflammatory reaction.
May occur at any age. Highly associated with smoking. Presents as a painful red mass near the nipple, often described clinically as an “abscess,” but I&D/abx are NOT effective.
Effective treatment requires complete excision of affected ducts.
Reaction to mammary implant
Fibrous capsule formed by reaction to silicone gel leakage (this side). Importantly, this does NOT require rupture of the silicone implant – simple leakage can cause these changes. Epithelial lining described as “synovial-like metaplasia” (front).
May be associated with breast implant-associated anaplastic large cell lymphoma (BIA-ALCL; CD30+, EMA+, ALK negative; Driven by JAK1 or STAT3 mutations). Mean time to development is 8-10 years, mean age of onset 51 years. Relative risk is 70x higher with textured breast implants. Risk possibly mitigated by antibacterial implantation practices.
Lupus mastitis
Lymphocytic vasculitis of small to medium-sized blood vessels. Subcutaneous and/or mammary adipose
tissue infiltrated by lymphocytes and
plasma cells (lobular > septal); germinal
center formation may be seen. Hyaline fat necrosis characteristic (shown).
If you are ever about to diagnose fibromatosis in the breast, . . .
throw on a keratin to rule-out fibromatosis-like metaplastic breast carcinoma.
Histiocytoid carcinoma – a variant of lobular breast carcinoma
Looks a LOT like fat necrosis.
