Breast – Malignant, Males, Children - Mucinous / colloid carcinoma

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Breast-malignant, males, children

Mucinous / colloid carcinoma

Author: Nat Pernick, M.D, PathologyOutlines.com, Inc.

Reviewer: Daniel Visscher, M.D., University of Michigan Hospitals, February 2009 (see Reviewers page)

Revised: 13 September 2009

Last major update: September 2009

Definition / pathophysiology

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● Clusters of small uniform cells floating in lakes of extracellular mucin

● Mucin accumulation may be due to inversion of polarity in cell, with mucin secretion directed towards base of cell / stroma, rather than luminal border; tumor cells also produce MUC2, a distinctive mucin type (AJSP 2003;27:571, Hum Path 1998;29:1517, Histopathology 2003;42:26)

● Classified as type A (paucicellular / no neuroendocrine differentiation), type B (hypercellular / neuroendocrine differentiation) or AB (intermediate form), although no clinical significance

● Based on molecular studies, mucinous type A is distinct from mucinous type B, and mucinous type B is part of a spectrum with neuroendocrine carcinoma (Mod Pathol 2009 Jul 24 [Epub ahead of print])

● Pure if 90% of more mucinous/colloid component

● Cases with 75-90% mucinous/colloid component are considered a mixed variant with a prognosis worse than pure mucinous carcinoma and dependent on the grade of the remaining carcinoma component

● Dictionary definition of colloid: (a) gelatinous material resulting from colloid degeneration in diseased tissue; (b) resembling product of thyroid gland; (c) system in which finely divided particles are dispersed within a continuous medium in a manner that prevents them from being filtered easily or settled rapidly

Terminology

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● Also called gelatinous carcinoma

Epidemiology

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● 0.5 to 3% of breast carcinomas (Cancer Radiother 2009;13:37)

● Usually older women (mean age 71 years, Breast Cancer Res Treat 2008;111:541) with slow growing tumor

Clinical

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● Nodal metastases are rare (2-4%), but important prognostic factor (Am J Surg 2004;187:528)

● Usually no nodal metastases for tumors < 1 cm (Am J Surg 2008;196:549)

● Micropapillary architecture has no clinical significance (Int J Surg Pathol 2008;16:251 but see Breast J 2008;14:412)

Treatment and prognosis

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● 10 year survival for pure form is >90% (much better than ductal carcinoma NOS)

● Death may occur late, although 20 year breast cancer specific survival is still >80%

● Pure cases may not need axillary staging (Ann Surg Oncol 2002;9:161)

Case reports

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● Case of the week #11

● 35 year old woman with locally advanced tumor and sudden growth (Japanese J Clin Oncol 2002;32:64)

● 36 year old woman with tumor arising within fibroadenoma (Pathologica 2008;100:199)

● 42 year old woman with aggressive, HER2+ tumor (Am Surg 2008;74:113)

● 74 year old man (Gac Med Mex 2007;143:79)

● 86 year old man with tumor presenting as Paget’s disease of nipple (Diagn Pathol 2008 Oct 24;3:42)

● Giant (17 cm) tumor (Breast Cancer 2005;12:337)

● Vulvar tumor due to ectopic breast tissue (Archives 2002;126:1216)

Gross description

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● Soft, pale, gray-blue, gelatin-like, well circumscribed

● Frequently hemorrhagic

Gross images

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Soft, gelatinous mass AFIP Tumor with positive margin (Fig 1A/1B)

Gelatinous tumor

Other images: Soft, gelatinous mass #1; #2

Microscopic description

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● Well differentiated (low grade) tumor cells floating in a sea of lightly staining amorphous mucin

● Tumor cells may be solid, acinar or detached

● Often surrounded by connective tissue bands

● Recommended that at least 1/3 of tumor volume should consist of mucin, and that no areas of typical invasion should be present (Stanford University)

● No/rare mitotic figures

● Usually no in-situ epithelial component

● Note: recommended to designate tumors as pure (at least 90% mucinous component) or mixed

Micro images

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Abundant mucinous stroma containing epithelial tumor cells with at most mild atypia

Images from Case of the Week #11

AFIP Images

Clusters of tumor cells Alveolar and festoon Sparse epithelial

in mucinous secretion patterns surrounded component (arrow-DCIS)

surround a duct by mucin

With micropapillary DCIS Nodal metastasis with similar histology

Ectopic breast tissue in vulva: Fig 1-mucinous lakes with clusters

of tumor cells and adjacent benign breast tissue; Fig 2-ER+; Fig 3-BRST1+

ER+, PR+, chromogranin+, Tumor cells are Argyrophilic cells (bind silver salts

synaptophysin+ ER+ and are made visible with reducing

agents - indicates neuroendocrine

differentiation)

EMA/MUC1 shows reverse WT1 staining

polarity staining pattern

Grimelius staining (an agryophilic silver stain)

denotes neuroendocrine differentiation (AFIP)

Cytology description

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● Highly cellular, loosely cohesive clusters and dissociated cells with intact cytoplasm and nuclei with mild atypia, no oval bare nuclei

● Also thin walled capillaries, micropapillary pattern of angulated clusters or abortive papillae and ball-like clusters (Acta Cytol 2007;51:25), abundant extracellular mucin (Malays J Pathol 2000;22:65)

● May have spindle cells at edge of nests and in background, which represent either tumor cells compressed by mucin or fibroblasts (Diagn Cytopathol 2009;37:393)

● Variable psammoma bodies (Diagn Cytopathol 2007;35:230)

Cytology images

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Colloid carcinoma

Tumor micropapillae admixed Tumor micropapillae with Mucinous carcinoma cell

with scattered, isolated tumor abortive branching, clusters with prominent

cells and mucoid substance in but no fibrovascular nuclear hobnailing and

the background (cytospin) cores (cytospin) psammoma body (upper left)

Mildly pleomorphic tumor cells Micropapillary/pseudoacinar

in monolayered sheet mimic cellular arrangement (cell block)

benign lesion, some tumor

cells show apocrine metaplasia

Fig C: FNA shows tightly Fig C: FNA shows carcinoma

cohesive tumor cells in cells embedded in mucin

mucinous background

Other images: colloid carcinoma

Virtual slides

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Mucinous / colloid carcinoma

Videos

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● Mucinous / colloid carcinoma

Positive stains

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● ER, PR (<70%), MUC2

● Neuroendocrine differentiation (chromogranin, synaptophysin, neuron-specific enolase) in 15-50% (AJSP 1994;18:702)

● Mucin stains with PAS, Alcian blue and mucicarmine

● Also WT1 (65%, Mod Path 2008;21:1217)

Negative stains

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● MUC1 (or low, Histopathology 2003;42:26), p53, HER2 (Kaohsiung J Med Sci 2005;21:197)

Molecular / cytogenetics

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● Usually diploid

Electron microscopy

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● Differences exist between cells of pure and mixed forms (Ultrastruct Pathol 2007;31:263)

Electron microscopy images

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Cytoplasmic mucigen granules

Differential diagnosis

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● Infiltrating ductal carcinoma with focal mucinous change

● Invasive micropapillary carcinoma - less extracellular mucin than mucinous carcinoma; cells have abundant eosinophilic cytoplasm, round vesicular nuclei and prominent nucleoli; extensive true angiolymphatic invasion; often psammoma bodies

● Metastatic mucinous carcinoma (rectum-Asian J Surg 2006;29:95)

● Mucinous DCIS - noninvasive, myoepithelial cells (calponin+, p63+) are present

● Mucocele-like lesion - myoepithelial cells are present and adherent to strips of cells floating in mucin, also ducts extended by mucinous material

● Myxoid fibroadenoma - has compressed spaces lined by 2 layers

● Signet ring carcinoma - intracellular mucin only

● FNA: infiltrating ductal carcinoma - marked atypia (AJCP 2003;120:194)

● FNA: myxoid fibroadenoma - stromal fragments and oval bare nuclei in every case

End of Breast – Malignant, Males, Children >Mucinous / colloid carcinoma

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