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 +
Perineurioma
-‐ Tumors where vast majority of cells show perineurial differentiation
-‐ Forms: intraneural, extraneural (soft tissue), sclerosing and reticular
-‐ Intraneural: formation of tiny “onion bulbs” (EMA+, S100+)
-‐ ST: ~ BFH or myxoid NF (EMA+, S100 –ve)
Ossifying fibromyxoid tumor of soft parts
-‐ Rare mesenchymal neoplasm first described by Enzinger in 1989.
-‐ Possible neuroectodermal origin
-‐ Approximately 70% of cases arise in the extremities
-‐ HIsto: lobules of uniform, round to fusiform-‐shaped cells in nests and cords, set in a fibromyxoid stroma, and surrounded by an incomplete shell of metaplastic (hypocellular) lamellar bone
-‐ IHC: vimentin and S-‐100 protein + (70%). Also desmin positivity, Leu-‐7, NSE, GFAP and SMA+
Granular cell tumor
-‐ Most tongue then cheek. Rarely parotid. Can be multiple (in blacks pts)
-‐ S100+ (supportive of schwan cell origin-‐ “granular cell schwannoma”)
-‐ NK1C3+, CD68+, Leu7+, NSE+, MBP+, GFAP neg, neurofilament neg
Congenital epulis of the newborn (congenital granular cell lesion)
-‐ Likely myofibroblastic in origin
-‐ 10% multiple. 90% females. MX>MD. On alveolar ridge (rarely on tongue also)
-‐ Never has PEH. S100-‐ (vs GCT); KP-‐1+, vimentin+
Extracranial meningioma
-‐ Arises from ectopic arachnoid lining cells
-‐ Type 1: Congenital. Skin of the scalp, forehead and paravertebral. Abnormal neural tube closure.
-‐ Intermediate between meningocele and meningioma (aka meningeal hamartoma)
-‐ Type 2: adults. Close to sensory organs (eye, ear, nose).
-‐ Syncitial pattern, swirling whorled balls of cells, collagenous septa, psammoma bodies. CK+
Glial heterotopia (nasal glioma, glial hamartoma, heterotopic glial tumor)
-‐ Congenital displacement of neuroglial tissue (variant of encephalocele)
-‐ 60% subcutaneous tissue of nose, 30% nasal cavity
-‐ Polypoid mass in nose of infant, grows with infant
-‐ If in mouth: glial choristoma
-‐ Histo: mats of glial tissue, with astrocytes; sneuronal elements absent.
-‐ IHC: glial fibrillary acidic protein (GFAP) and S100+
Encephalocele
-‐ Similar to glial heterotopia, but maintains connection with CNS via defect in cribiform plate
-‐ If in nose, virtually indistinguishable from glial heteropia
-‐ Histo: mixture of astrocytes, glial fibers andneuronal elements
Multiple endocrine neoplasia 2B (MEN3, multiple mucosal neuroma syndrome)
-‐ MEN1 (Werner syndrome): 3Ps (benign tumors of parathyroid, pancreas, and pituitary tumors)
-‐ MEN2A (Sipple syndrome): Pheochromocytoma and medullary thyroid ca.
-‐ MEN2B: Pheo (50%), medullary thyroid ca. (90%) and mucosal neuromas. RET mutation (chr 10)
-‐ MEN2B: protuberant lips in narrow face, eversion of eyelids.
-‐ Neuromas: lips, anterior tongue, bilaterally on commissures
-‐ Marfanoid body: thin long limbs and muscle wasting
-‐ Increased serum or urinary calcitonin (if med thyr ca is present)
-‐ Pheo: vanillylmandelic acid and epi/norepinephrine ratio (also in MNET and neuroblastoma)
Melanotic neuroectodermal tumor of infancy
-‐ Aka pigmented ameloblastoma, retinal anlage tumor and melanotic prognoma (no longer used)
-‐ Neural crest origin; < 1y, MX, M>F; sunray pattern on xray
-‐ Biphasic (NSE and CD56+ small round cells, CK+ epitheliod cells)
-‐ Elevated levels of vanillylmandelic acid (also seen in pheo.)
Paraganglioma (chemodectoma)
Carotid body
-‐ Paraganglia: chemoreceptors that detect changes in blood pH and O2 tension
-‐ Neural crest origin. May arise as a response to hypoxia (more in females at higher altitutes)
-‐ Deep mass below angle of MD with pharyngeal swelling
-‐ Fontaine’s sign: lesion moved side to side, but no vertical movement
-‐ 10% multifocal, 10% familial history (genomic impriting), 10% metastasize
-‐ Chief cells (type 1) and sustentacular cells (type 2) organized in zellballen, highly vascular
-‐ Carney’s triad: extra-‐adrenal paraganglioma, gastric leiomyosarcoma and pulmonary condroma
-‐ Chief cell: synaptophysin, chromogranin and NSE+; sustentacular cell S100 +
-‐ Malignant: if metastasis is present
Paraganglioma (chemodectoma)
Jugulotympanic paraganglioma (glomus jugulare)
-‐ Paraganglia of auricular branch of vagal nerve or tympanic branch of glossopharyngeal nerve
-‐ Develop in temporal bone and middle ear
-‐ Glomus jugulare: when arising from the jugular bulb
-‐ Glomus tympanicum: involving the middle ear (most common neoplasm of this region)
Paraganglioma (chemodectoma)
Vagal paraganglioma (vagal body tumor)
-‐ Develop as high cervical masses between mastoid process and angle of the jaw
-‐ Lie above the carotid bifurcation, w/o widening of the bifurcation point
Glomus tumor
-‐ Glomus body: regulates temperature and is an AV shunt
-‐ Sucquet-‐Hoyer canal: arterial segment of the glomus body
-‐ Varying proportions of glomus cells, blood vessels and smooth muscle
-‐ Papulonodular lesions, red/pink/blue, extremely painful.
-‐ Acral distribution (hand, foot and forearm)
- Types: solid, glomangioma, glomangiomyoma (60%), infiltrating and glomangiosarcoma
- Glomangioma: Cookie-‐cutter cells (prominent cell borders); round, centrally placed, almost neuroendocrine-‐like; cells surround vascular “lakes”
- Glomangiomyoma: SMC near vascular spaces and bleding with glomus cells
Hemangioma and vascular malformations
-‐ Arise during first 8 wks, involutes
-‐ Vascular malformation: present at birth, no involution
-‐ Hemangioma: most common tumor of infancy, more in females (5:1), 60% HN
-‐ PHACES syndrome: Posterior fossa brain anomaly (Dandy-‐Walker), Hemangioma, Arterial anomalies, Cardiac defects, Eye anomalies, and Sternal cleft/supraumbilical raphae
-‐ Kasabach-‐Merritt phenomenom: thrombocytopenia and hemorrhage due to platelets being trapped in tufted hemangioma and kaposiform hemangioendothelioma
-‐ Intrabony hemangioma: bruit or pulsation may be present. ML or UL RL or sunburst
-‐ Histology: juvenile or cellular (aka juvenile hemangioendothelioma); capillary; cavernous
-‐ Juvenile hemangioendothelioma is the most common SG tumor of infants
-‐ GLUT1: positive in hemangioma of infancy, but negative in vascular malformations
Intravascular papillary endothelial hyperplasia (Masson’s tumor, Masson’s hemangioma)
-‐ Reactive pseudoneoplastic proliferation of endothelial cells associated with thrombosis
-‐ Histo: dilated vascular channels containing endothelial-‐lined papillary fronds and stroma
Sturge-‐Weber angiomatosis (encephalotrigeminal angiomatosis)
-‐ Port wine stain (nevus flammeus), leptomeningeal angiomas, seizures and mental retardation
-‐ Gingiva may become hyperplastic or with PG (from vascular component or use of phenytoin)
-‐ Tramline calcifications on skull film
Klippel-‐Trenaunay-‐Weber syndrome
-‐ Multiple facial hemangiomas, vascular masses w/ enlargement of extremities, ocular disorders
-‐ Premature tooth eruption and bony overgrowth may cause malocclusion
-‐ Ddx: Sturge-‐Weber and Maffucci syndromes
Nasopharyngeal angiofibroma
-‐ Exclusive in young males (10-‐17y). Arises in pterigopalatine fossa
-‐ Imaging: anterior bowing of posterior wall of mx sinus - Hollmann-Miller sign
- Angiogram useful.
Hemangiopericytoma-‐solitary fibrous tumor
-‐ 75% cheek; common on pleura
-‐ HPC: Tighly packed cells that surround staghorn vessels
-‐ Spindle cells in short fascicles or in “patternless pattern”.
-‐ Alternating hyper/hypo cellular zones (latter contains prominent hyalinized collagen bundles)
-‐ Bands of dense collagen separate individual cells
-‐ Myxoid, bluish background around islands of pleomorphic, bland cells
-‐ HPC-‐like areas with stag-‐horns
-‐ CD34+, CD99+, bcl-‐2+, SMA –ve
Glomangiopericytoma (sinonasal hemangiopericytoma, glomus tumor, HPC-‐like tumor)
-‐ Distinct entity from soft tissue hemangiopericytoma
-‐ Monomorphic spindle to ovoid cells with lightly eosinophilic cytoplasm and bland nuclei forming short fasciles or a storiform, whorled or palisated pattern.
-‐ Tumor cells aggregate around staghorn vessels
PEComa (perivascular epithelioid cell neoplasm)
-‐ Family of tumors derived from perivascular epitheliod cells
-‐ Includes: renal angiomyolipoma, lymphangiomyomatosis and clear cell “sugar” tumor of lung
-‐ Associated with tuberous sclerosis complex
-‐ Express melanocytic and muscle markers. Can look like a granular cell tumor.
-‐ Lymphangiomyomatosis seen exclusively in women of child-‐bearing age
Lymphangioma
-‐ Simplex (capillary), cavernous and cystic (cystic hygroma). 50-‐75% HN; 90% < 2yo
-‐ Cystic: most in post triangle of neck. Ant lesions more complications.
-‐ Oral: ant 2/3 tongue (frog eggs or tapioca pudding).
-‐ 4% of black neonates have small lesions of the alveolar ridge
Leiomyoma
-‐ Most in uterus, GI tract and skin.
-‐ Histo: solid, angioleiomyoma, and epithelioid leiomyoma (leiomyoblastoma)
-‐ Masson trichrome stains muscle red. SMA+ MSA+
Rhabdomyoma
-‐ Adult (pharynx, larynx, mouth-‐FOM, soft palate, base of tongue) and fetal (face, periauricular)
-‐ Adult: spider-‐web appearance (peripheral vacuoles with filaments)
-‐ Fetal: haphazard spindle cells (muscle-‐looking) within a myxoid stroma
-‐ IHC: myoglobin+, desmin+, MSA+, PTAH+ (myofibrils stain purple)
Osseous and cartilaginous choristoma
-‐ Choristoma: normal tissue in abnormal location; Hamartoma: excess tissue in normal location
-‐ 85% posterior tongue, 70% women
Ectomesenchymal chondromyxoid tumor
-‐ Always on anterior tongue
-‐ Well defined multilobulated. Spindle to round cells in a myxoid or chondroid backgound. GFAP+
Multinucleate cell angiohistiocytoma
-‐ Chronic inflammatory disorder of unknown cause
-‐ Multiple, firm, red-‐purple, dome-‐shaped, coalescing/linearly arranged papules on skin of limbs
-‐ Histo: proliferation of small blood vessels with unusual dendritic cells and multinucleate cells
-‐ IHC: EC-‐ Factor VIII-‐RA, CD34, CD31+; DC-‐ Factor XIIIa, lysozyme, α1-‐antichymotrypsin, vimentin, CD68; giant cells-‐ vimentin only
Fibrosarcoma
-‐ Most in deep soft tissues of the lower extremities, especially thigh and knee
-‐ Herring-‐bone pattern: fascicles of spindle cells
-‐ DDx: especially monophasic synovial sarcoma, MPNST and MDH
Infantile fibrosarcoma (congenital fibrosarcoma, aggressive infantile fibromatosis)
-‐ Either congenital or within first year of life
-‐ Histo: identical to adult fibrosarcoma, but HPC-‐like growth pattern more prominent
-‐ 12;15 genetic translocation (producing ETV6-‐NTRK3 fusion protein)
Dermatofibrosarcoma protuberans
-‐ Translocation 17;22 (Col11A1-‐PDGF fusion and increase in PDGF chain)
-‐ Old fashion bathing suit distribution
-‐ Histo: monotonous haphazard storiform arrangement of spindle and stellate cells that infiltrates and entraps adnexa and adipose. Low mitoses
-‐ IHC: CD34+; factor XIIIa neg (vs. BFH, CD34 neg, XIIIa +)
-‐ Bednar’s tumor: pigmented DFSP
-‐ Giant cell fibroblastoma: juvenile form of DFSP
Malignant fibrous histiocytoma
-‐ Most common in older patients
-‐ Storiform pattern
Liposarcoma
-‐ Most common STS (20% of all malignancies in adults)
-‐ Most in thigh, retroperitoneoum and inguinal.
-‐ Types: WD/ALT (most common in oral cavity); myxoid/round cell; pleomorphic; dedifferentiated
-‐ Pleomorphic worse prognosis
Malignant peripheral nerve sheath tumor
-‐ 50% in pts with NF1.
-‐ Proximal extremities and trunk.
-‐ X-‐ray: widening of MD canal or mental foramen
-‐ Malignant Triton tumor: MPSNT + malignant skeletal muscle
-‐ Pts with MPNST and NF1 are 10y younger (35 vs 45) and worse prognosis than w/o NF1
-‐ Low-‐power: distinctive perivascular tumor cells surrounded by necrosis
-‐ IHC: S100 in only 50% of cases
Angiosarcoma
-‐ Most in scalp and forehead (early lesion resembles a bruise)
-‐ Hemangioendothelioma: intermediate between hemangioma and angiosarcoma
-‐ IHC: CD31+, factor VIII+, CD34 less consistent
-‐ Associated with the environmental carcinogen vinyl chloride (PVC)
-‐ Stewart-‐Treves sydrome: angiosarc assoc w/ chronic lymphedema
-‐ Radiation also risk factor -‐> increased incidence in women with hx breast cancer
-‐ Better prognosis for oral and SG tumors
Kaposi sarcoma
-‐ Classic, endemic (benign, aggressive, flord, lymphadenopathic), iatrogenic and AIDS-‐related.
-‐ Stages: Patch, plaque, and nodule.
-‐ Promontory sign: normal structures admixed with tumor proliferation (patch stage)
Leiomyosarcoma
-‐ Most in uterine wall and GI tract.
-‐ Epithelioid leiomyosarcoma: composed entirely of rounded cells
-‐ Some associated with RBI mutation
-‐ PAS shows glycogen within the cells. Cell cytoplasm red on Masson trichrome
-‐ MSA (HHF35)+, SMA+, desmin+, H-‐Caldesmon+, smooth muscle myosin (SMMS)+
Rhabdomyosarcoma
-‐ 60% of STS in children
-‐ Embryonal (NOS, botryoid, spindle), alveolar, undifferentiated and anaplastic
-‐ Age: embryonal (<10y), alveolar (10-‐25y) and pleomorphic (>40y)
-‐ HN (face/orbit) and GU tract. Oral RMS: palate and max sinus. Most common sarcoma children.
-‐ Embryonal: round, spindle and strap cells
-‐ Rhabdomyoblasts: small cells with dark nuclei and deeply pink cytoplasm
-‐ Botryoid: lesions that arise in cavity (mouth, vagina) with exophytic, polypoid growth
-‐ Cambium layers: zone of increased cellularity just below mucosa (botryoid RMS)
-‐ Alveolar: PAX3-‐FKHR and PAX7-‐FKHR translocation
-‐ Embryonal: 11p15 LOH
-‐ Myogenin, MyoD1, HHF-‐35 +
Alveolar soft part sarcoma
-‐ X;17 translocation (ASPL-‐TFE3 fusion protein generated).
-‐ Young pts: orbit and tongue, more females. Adults: lower extremities, more in males
-‐ Discohesive cells in nests, minimal atypia, vascular invasion
-‐ IHC: TFE3+ (only marker)
-‐ Crystals: aggregates of the MCT1 protein and its chaperone, CD147.
-‐ Crystals are PAS+, diastase resistant (on EM: latticework pattern)
Synovial sarcoma
-‐ X;18 translocation (SYT gene chr 18 and SSX1/SSX2 on gene X)
-‐ SYT/SSX fusion mRNA can be detected by RT-‐PCR or FISH
-‐ Most near large joints and bursae of extremities. HN: paravertebral and parapharyngeal mass
-‐ Classically biphasic (spindle cells ~ fibrosarcoma + epith cells surrounding glandlike spaces or forming nests, cords or whorls). “slit-‐oma”. Calcifications in 30%. Stag-‐horn vessels.
-‐ CK+, EMA+, CD99+
Follicular dendritic cell sarcoma
-‐ Arises from dendritic cells (antigen-‐presenting cells) of the immune system
-‐ Predilection for LN of the neck, axilla and mediastinum
-‐ Histo: syncitial-‐appearing spindly cell that form fascicles or whorls
-‐ CD21, CD35+
Ewing sarcoma/primitive neuroectodermal tumor (PNET)
-‐ Composed of small, undifferentiated round cells (prob neuroectodermal)
-‐ Usually whites < 20 yo, MD. Fever, increased ESR, leukocytosis (similar to osteomyelitis)
-‐ 11;22 translocation. CD99+ (MIC2 gene product). FISH against the translocation more specific.
-‐ Long bones have “onionskin” (seldom seen in jaws)
-‐ Large cell (atypical) Ewing sarcoma: composed mostly of larger cells
-‐ Histo:
-‐ 75% contain glycogen granules in cytoplasm
-‐ Pelvic lesions and proximal lesions have poorer prognosis
Metastases to the oral soft tissues
-‐ Gingiva (~PG) (50%) and tongue (25%)
-‐ Batson’s plexus: implicated in metastases to the jaws that bypass filtration through the lung
-‐ Men: lung, renal, melanoma (prostate goes to bone)
-‐ Women: breast (IHC: PR, ER+), genital, lung, bone, kidney
