Breast-nonmalignant - Fibromatosis

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Breast-nonmalignant

Benign tumors / changes

Fibromatosis of breast

Reviewer: Hind Nassar, M.D. in January 2009 (see Authors page)

Revised: 18 July 2010, last major updated April 2010

Definition

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● Rare clonal proliferation of fibroblasts and myofibroblasts similar to counterparts elsewhere

Terminology

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● Also called desmoid tumor-extraabdominal type

Epidemiology

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● Rare (< 0.2% of primary breast tumors)

● Usually women of childbearing age, may be associated with trauma (Hum Pathol 2009;40:1564)

Sites

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● May arise in mammary gland or in chest wall musculoaponeurotic tissue and extend into breast

Etiology

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●

Clinical features

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● Infiltrative, locally recurrent if positive margins (25%) but nonmetastasizing (Am J Surg Pathol 1979;3:501, Am J Surg Pathol 1987;11:38)

Prognostic factors

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Case reports

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● 22 year old woman post-silicone breast implant (J Plast Reconstr Aesthet Surg 2010;63:339)

● 39 year old woman with mass resembling carcinoma (Arch Pathol Lab Med 1985;109:260

● 47 year old man with rapidly growing mass (Clinics 2006;61(4))

● 70 year old woman with infiltrating ductal carcinoma and subsequent fibromatosis (World J Surg Oncol 2006;4:57)

Treatment

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● Wide local excision with careful attention to negative margins, although may recur even with negative margins (Ann Surg Oncol 2008;15:274)

Clinical images

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Gross description (Macroscopy)

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● Ill defined, white-tan-gray fibrous tissue

Gross images

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Solid ill defined mass Residual fibromatosis along En bloc resection of underlying chest wall

inferior aspect of biopsy cavity musculature, ribs, and parietal pleura for

recurrent tumor

Micro description (Histopathology)

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● Irregular, nonencapsulated proliferation of spindle cells forming interlacing fascicles with variable collagen deposition and cellularity

● Usually extends into surrounding fat and glandular parenchyma

● May have focal lymphoid aggregates at periphery

● May contain eosinophilic inclusions similar to those of infantile digital fibromatosis

● No/rare mitotic figures

● No epithelial component

Micro images

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Various images

Neoplastic infiltrate surrounds Sparsely cellular collagenous

ducts and lobules area with lymphocytes

Spindle cells with uniform nuclei Keloidal collagen surrounds

and no mitotic activity atrophic duct

Spindle cells in myxoid stroma Focally, cells have large

hyperchromatic nuclei

Long interlacing fascicles of bland spindle Bland fibroblasts entrapping

cells with moderate collagen deposition benign ducts and fat

and focal hyalinization

Fibromatosis with adjacent Myofibroblastic spindle cells with indistinct cytoplasm,

ductal epithelium vesicular nuclei, small nucleoli and interstitial collagen

Infiltrative tumors Bland fibroblasts of Various images

moderate cellularity

Fig A: infiltration into adjacent breast tissue

Fig B: infiltration into skeletal muscle

Fig C: monotonous, bland spindle cells with abundant

extracellular collagen, occasional small nucleoli

Smooth muscle actin+ Cytokeratin negative

Virtual Slides

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Videos

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Cytology description

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● Hypocellular spindle cells with no/rare glandular elements

Cytology images

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●

Positive stains

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● Vimentin, smooth muscle actin (focal)

Negative stains

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● ER, PR (but see Arch Pathol Lab Med 1987;111:870)

● Androgen receptor (Arch Pathol Lab Med 2000;124:276)

● CD34

Electron microscopy descriptions

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● Fibroblasts and myofibroblasts

Electron microscopy images

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Molecular / cytogenetics description

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● Nuclear accumulation of beta-catenin in stromal tumor cells (82%), somatic alterations of APC/beta-catenin pathway (79%, Hum Pathol 2002;33:39)

Molecular / cytogenetics images

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Differential Diagnosis

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● Benign stromal spindle cell tumors: circumscribed, no collagen,CD34+

● Fibrous histiocytoma: storiform pattern of spindled and bland fibroblasts and histiocyte-like cells in mid-dermis and subcutaneous tissue with infiltrative margins but sparing epidermis

● Inflammatory pseudotumor: prominent inflammatory infiltrate

● Metaplastic carcinoma, fibromatosis-like subtype: epithelial component is atypical, keratin+

● Nodular fasciitis: superficial, well circumscribed, zonation effect with hypocellular central region and hypercellular periphery; feathery, tissue-culture like growth pattern due to abundant ground substance; often with mucoid pools (microcysts)

● Phyllodes tumor, stromal component

Additional references

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End of Breast-nonmalignant > Benign tumors / changes > Fibromatosis of breast

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