Ch. 20 - Fibrous tumors Flashcards
Dermatofibroma
Interstitial spindle cells with collagen trapping and overlying acanthosis. Ringed lipidized siderophages. Factor XIIIa+, CD34-.
Aneurysmal dermatofibroma (sclerosing hemangioma)
A type of dermatofibroma with aneurysmal dilatation of vessels.
Fibrous histiocytoma
A type of dermatofibroma with large histiocytoid vesicular nuclei with prominent nucleoli.
Dermatofibroma with monster cells
A type of dermatofibroma with very large cells with vesicular nuclei and prominent nucleoli. Benign!
Adult myofibroma
Blue myxoid nodules with myofibroblasts and peripheral fibrovascular proliferation.
Dermatomyofibroma
Plaque-like tumor with horizontally-aligned spindle cells which “respect” adnexal structures.
Fibromatosis
Corkscrew-shaped myofibroblasts and collagen. Locally infiltrate but not metastatic.
Infantile myofibromatosis
Fibromatosis in children which tends to spontaneously regress (become less cellular and more fibrous). Visceral inolvement can be fatal.
Juvenile hyaline fibromatosis
(cause?)
Nodular hyaline fibrosis in the dermis. Affects face, hands, joints, gingiva.
AutRec CMG2/ANTXR2 mutations
Scar, hypertrophic scar, keloid
Scar: Horizontally-aligned fibroblasts and vertically-aligned blood vessels. No elastic tissue.
Hypertrophic: Whorled proliferation
Keloid: Central bundles of amorphous “bubble-gum” collagen.
Fibrous hamartoma of infancy
Disordered myxoid and mature fibrous and fatty areas with compartmentalized appearance.
Infantile digital fibroma (inclusion body fibroma)
Criss-cross fascicles of spindle cells with red inclusion bodies (actin?).
Giant cell tumor of the tendon sheath
Osteoclast-like giant cells (randomly distributed nuclei) with plump fibroblasts and collagen+hemosiderin.
Fibroma of tendon sheath
Essentially, giant cell tumor of tendon sheath without the giant cells. Bland, plump fibroblasts.
Elastofibroma dorsi
Large fibrous tumor with deposits of beaded elastic fibers.
Sclerotic fibroma
(association?)
“Starry sky” whorls of hypocellular collagen.
Associated with Cowden’s syndrome
Pleomorphic fibroma
Scattered large hyperchromatic stellate nuclei. No mitoses! CD34+.
Sclerosing perineurioma
Whorled, nodular, or storiform concentric appearance. EMA+.
Angiofibromas
Concentric perivascular fibrosis with stellate, factor XIIIa+ stromal cells.
Fibrous papule of the face (benign fibrous papule, solitary angiofibroma)
Common type of angiofibroma with large pyramid-shaped melanocytes at the dermal-epidermal junction.
Acquired digital fibrokeratoma
An acral angiofibroma with hyperkeratosis, acanthosis, and hypergranulosis.
Nodular fasciitis
“Tissue culture” loose myxoid pattern of fibroblasts with erythrocytes and inflammatory cells.
Cranial fasciitis, proliferative fasciitis
Cranial: Variant of nodular fasciitis that occurs on head of a child
Proliferative: Variant of nodular fasciitis with ganglion-like giant cells and peripheral collagen trapping
Calcifying aponeurotic fibroma
Plump, epithelioid fibroblasts palisading around chondroid foci sometimes with calcification and/or osteoclast-like cells.
