Chaper 12: Soft tissue tumors Flashcards
Fibroma
-‐ Frenal tag: fibrous hyperplasia, most frequent on maxillary labial frenum
-‐ Giant cell fibroma: true tumor. Papillary surface
-‐ Retrocuspid papilla: bilateral GCF on gingival lingual to MD canines, disappears with age
Inflammatory fibrous hyperplasia (epulis fissuratum)
-‐ Hyperplasia of fibrous tissue in association with ill-‐fitting complete or partial denture
-‐ Leaflike denture fibroma (fibroepithelial polyp): on hard palate beneath denture
Inflammatory papillary hyperplasia
-‐ Usually beneath a denture; If dentate, mouth breathers or with deep palatal vault
Benign fibrous histiocytoma (dermatofibroma)
-‐ Aka sclerosing hemangioma, fibroxanthoma and nodular subepidermal fibrosis
-‐ Most common site: skin of extremities.
-‐ Cells arranged in short, intersecting fascicles: storiform (whorled straw mat) or cartweel pattern
-‐ Fibroblasts, histiocytes and Touton giant cells. Also xanthoma cells, lymphocytes, HPC-‐like areas
-‐ Collagen trapping: keloidal collagen
-‐ Factor XIIIa +; CD34 –ive (vs DFSP XIIIa –ve and CD34+)
-‐ Variants: cellular (higher recurrence), epitheliod (mimics Spitz nevus)
Juvenile xanthogranuloma
-‐ Sheets of histiocytes (xanthomatous), Touton giant cells (“wreath-‐like” nuclei arranged around the scalloped edge of the cell in a fluorette type). Eosinophils may be present
-‐ IHC: CD68, antitrypsin+, but S100 and CD1a negative
Reticulohistiocytoma (solitary epithelioid histiocytoma)
-‐ Histiocytic proliferation of skin or ST (CD163+, CD68+)
-‐ Large epithelioid histiocytes (with glassy cytoplasm), lymphocytes, neutrophils, giant cells
-‐ DDx: juvenile xanthogranuloma and Rosai-‐Dorfman
-‐ If generalized: multiple skin lesions and granulomatous polyarthritis
Xanthoma
-‐ Localized collection of tissue histiocytes containing lipid (not a true tumor)
-‐ Develop in most primary and some 2ary hyperlipoproteinemias
-‐ Xanthelasma: xanthomas of the eyelid, usually in normolipemic persons
Fibromatosis (desmoid tumor, juvenile aggressive fibromatosis, extra-‐abdominal fibromatosis)
-‐ Group of fibrous proliferations intermediate between benign lesions and fibrosarcoma
-‐ Bone: desmoplastic fibroma
-‐ Familial adenomatous polyposis and Gardner pts have higher risk for fibromatosis
-‐ Spindle cells infiltrate muscle and fat; cells run parallel to vessels and collagen runs along side each cell; abundant collagen (little or no cell-‐to-‐cell contact); lacks hyperchromasia
-‐ Multinucleated giant cells: atrophic skeletal muscle remnants (periphery of lesion)
-‐ IHC: vimentin, SMA, MSA, -‐catenin positivity
-‐ Fibromatosis colli (sternocleidomastoid tumor): most common type, seen few weeks after birth
Juvenile hyaline fibromatosis
-‐ Hereditary condition characterized by multiple cutaneous papules, nodules or masses, gingival hyperplasia, joint contractures and osteolytic defects
-‐ Histo: chords of spindle cells embedded in a homogenous eosinophilic matrix
Myofibroma (myofibromatosis)
-‐ Proliferation of myofibroblasts.
-‐ If multicentric: myofibromatosis (neonates/infants with tumors of skin, bone, visceral organs)
– Predilection for H/N region, Most common oral sites = mandible, followed by tongue and buccal mucosa
-‐ May appear biphasic: darker central area and ligher peripheral areas
-‐ Nodules or whorls of elongated, spindle cells. Myxoid stroma, stag-‐horns, chondroid areas
-‐ May have smooth muscle/fibroblastic features, HPC-‐like pattern, local infiltration
-‐ HC: vimentin+, SMA+, PTAH+, desmin –ive, S100 –ive
Nodular fasciitis
-‐ Most in adults 20-‐40y, Classic clinical history of rapid growth, 50% of the cases with pain
-‐ Most in upper extremities, trunk and head/neck
– USP6-MYH9 gene fusion
-‐ Histo: red spindle cells, in fascicle and bundles; Feathery “tissue culture” apperance; keloid-‐like collagen fibers; inflammation, hemosiderin, extravasated RBC
-‐ IHC: KP-‐1+ (CD68 in intralesional histiocytes)
Keloid
-‐ Due to abnormal would healing in genetically predisposed individuals
-‐ Predilection for dark-‐skinned patients
-‐ Hypertrophic scar: remain confined to original wound site
-‐ Associate with Ehlers-‐Danlos, scleroderma and Rubinstein-‐Taybi syndrome
-‐ Histo: haphazardly arranged, thick, glassy, deeply eosinophilic collagen fibers
Inflammatory myofibroblastic tumor
-‐ Most common location is the lung; results from overexpression of ALK kinase
-‐ Dx of exclusion; lymphocytes, plasma cells, histiocytes, fibroblasts and myofibroblasts
-‐ Five patterns: (1) lymphoplasmatic (plasma cell granuloma) (2) lymphohistiocytic (~ infection)
(3) myofibroblastic (~ BFH and nodular fasciitis) (4) lymphoplasmacytic and collagenized (~ inflamed desmoid tumor) (5) atypical IMFT (cellular, ganglion-‐like cells and coagulative necrosis)
-‐ IHC: MSA, SMA, desmin and ALK-‐1 positivity
Oral focal mucinosis
-‐ Oral counterpart of cutaneous focal mucinosis or cutaneous myxoid cyst
-‐ Overproduction of hyaluronic acid by fibroblasts (Alcian blue+)
-‐ 75% gingiva; mostly in young females
-‐ DDx: soft tissue myxoma, myxoid NF, neurothekeoma (nerve sheath myxoma) (S100+)
Pyogenic granuloma
-‐ 75% gingiva (poor hygiene). Also tongue, cheek and lips (trauma related)
-‐ Granuloma gravidarum: increased levels of progesterone and estrogen
-‐ Epulis granulomatosa: PG in extraction socket
Peripheral giant cell granuloma
-‐ Blue-‐purple mass, exclusive to gingiva or alveolar ridge
Peripheral ossifying fibroma
-‐ Pink or red, exclusive gingiva (more ant MX), teenagers (females), incisor-‐cuspid area
Lipoma
-‐ Most common mesenchymal neoplasm
-‐ Most in trunk and proximal extremities, more in obese people
-‐ May show central cartiagenous or osseous metaplasia
-‐ Intramuscular lipoma has higher recurrence rate (due to infiltrative growth pattern)
-‐ Spinde cell lipoma: bland spindle cells, myxoid changes, ropy collagen bundles, scattered mast cells and mature adipocytes. CD34+
Lipoblastoma (lipoblastomatosis)
-‐ Composed of lipoblasts and adipocytes with fibrous connective tissue septa
-‐ Almost exclusive of children (<3 yo)
Hibernoma
-‐ Arises from vestigial remnants of brown fat
-‐ Multivacuolated cells resembling cells of brown fat of hibernating animals
-‐ S100+, CD34 –ve
-‐ Rearrangements of 11q13 and 11q21
Traumatic neuroma
-‐ Mental foramen, tongue and lower lip; trauma often present
-‐ Lesions of greater auricular nerve develop in 10% of Sx for PA
-‐ Pain in 25-‐33% of cases
Palisated encapsulated neuroma (solitary circumscribed neuroma)
-‐ 90% face (nose and cheeks)
-‐ Exhibits cracking artifact and “peeling”
Neurilemoma
(Schwannoma)
-‐ Associated with NF2
-‐ NF2: AD, MERLIN (schwannomin) gene mutation (chr. 22). Bilateral neurilemomas of the vestibular nerve (acoustic neuromas); neurilemmomas of peripheral nerves; meningiomas and ependymomas of CNS
-‐ Schwannomatosis: multiple neurilemomas w/o vestibular tumors
-‐ Carney syndrome: psamommatous melanocytic schwannomas
-‐ Verocay bodies: reduplicated basement membrane and cytoplasmic processes
-‐ Ancient schwannoma: hemorrhage, vessel hyalinization, pleomorphic cells, verocay bodies, xanthomatous changes, cysts, fibrosis and calcification
-‐ S100 stronger than in NF
-‐ Neurites absent
Neurofibroma
-‐ Most common peripheral nerve neoplasm
-‐ Mast cells tend to be numerous; Neurites present; “Shedded carrot” appearance
-‐ IHC: scattered positivity for S100
Neurofibromatosis (von Reclinghausen’s disease of the skin)
-‐ NF1: 50% AD, 50% new mutation (NF1 gene on chr. 17, neurofibromin protein)
-‐ Elephantiasis neuromatosa: large baggy neurofibromas
-‐ Plexiform neurofibroma: “bag of worms”, pathgnomonic for NF1 (esp in trunk)
-‐ NF Dx: café-‐au-‐lait (6+), axillary freckling (Crowe’s sign), brown pigmented spots on the iris (Lisch nodules), optic glioma
-‐ Oral: most common finding-‐ enlargement of fillifom papilla; 25% oral NF
-‐ NF1 assoc with Noonan syndrome and CGCG. HT most common problem. Can mimic hemifacial hyperplasia (macroglossia)
-‐ NF1: 5% NF transform in MPNST. Others: RMS, leukemia, pheochromocytoma and Wilm’s tumor
-‐ Elephant man (Joseph Merrick): Proteus syndrome (hamartomatous condition, PTEN mut)
*Order of neural lesions occurrence:
neuroma > schwannoma, NF > ancient schwannoma > plexiform NF
Ganglioneuroma
-‐ Average age a dx 6y; most common in mediastinum
-‐ GI polypoid GN assoc w/ Cowden, tuberous sclerosis, juvenile polyposis, NF1 and MEN2B
-‐ Histo: scattered clusters of ganglion cells scattered in a background of Schwann cells bundles
-‐ Ganglion cells: large pink cytoplasm and 1-‐3 nuclei
Neurothekeoma (nerve sheath myxoma)
-‐ Rare, adult, finger/hand
– Distinctively compartmentalized, due to prominent septa of fibrous tissue forming lobules
-‐ Each lobule consists of cells and myxoid stroma (hyaluronic acid or sulfated acid)
-‐ Cellular neurothekeoma: cellular, nuclear atypia, mitosis, extension into fat, muscle or vessels
-‐ DDx: focal mucinosis and myxoid neurofibroma (lobulation is key difference)
-‐ IHC: S100 and PGP9.5 +
