Angiofibroma and Related Lesions

 Solitary, dome-shaped, flesh-colored papules on nose or central face



• Adenoma sebaceum: Angiofibromas associated with tuberous sclerosis
image Grouped papules or nodules with butterfly distribution on central face

• May clinically mimic basal cell carcinoma




Microscopic




• Involves superficial dermis
• Scattered bland, spindled to stellate, and multinucleated fibroblasts

• Rare cases with epithelioid or clear cells

• Dense collagenous stroma

• Absence of solar elastosis

• Ectatic thin-walled blood vessels

• Clear cell FP

image Tumor cells have abundant clear vacuolated cytoplasm

• Epithelioid FP
image Sheets and small groups of epithelioid tumor cells

• Granular cell FP
image Tumor cells have abundant granular cytoplasm


Top Differential Diagnoses




• Dermatofibroma
image More cellular with collagen trapping

• Scar
image Horizontal arrangement of fibroblasts

• Xanthogranuloma
image Foamy histiocytes with admixed inflammatory cells

• Epithelioid cell histiocytoma
image Rare on face

image Epidermal collarette

• Intradermal nevus
image Nested pattern; melanocytic markers positive

• Cellular neurothekeoma
image Nested pattern

image
Fibrous Papule at Low Magnification
Fibrous papule (FP) is characterized by a dome-shaped lesion with ectatic thin-walled blood vessels image and a dense collagenous stroma.


image
Higher Magnification of Fibrous Papule
This higher power image of an FP demonstrates the relatively hypocellular proliferation of bland spindled to stellate fibroblasts, small ectatic vessels, and dense collagenous stroma.

image
Clear Cell Variant of Fibrous Papule
This example of clear cell FP is composed of epithelioid cells with abundant clear-staining cytoplasm image. The lesion also has an associated mildly collagenous stroma and a few small, dilated vessels image.

image
Epithelioid Variant of Fibrous Papule
Epithelioid FP is more cellular and shows a proliferation of round cells with eosinophilic cytoplasm image.


TERMINOLOGY


Synonyms




• Fibrous papule (FP), adenoma sebaceum, acral angiofibroma, pearly penile papule


Definitions




• Angiofibroma encompasses group of benign mesenchymal tumors characterized by spindled to stellate fibroblasts, dense collagenous stroma, and ectatic blood vessels
image May be related to proliferation of papillary dermal elements

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Apr 24, 2017 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Angiofibroma and Related Lesions
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