Random Tumours Flashcards
Morton’s Neuroma (Intermetarsal neuroma, or metatarsalgia)
Summary:
- benign neuroma but painful
- commonly affects the intermetatarsal plantar nerve of the second and third intermetatarsal space (ball of foot)
- solitary circumscribed, proliferation of nerve fibers
- arterial thickening and thrombi
- fibrosis (may be concentric) in and around nerves
- schwannian and fibroblast proliferation
- degenerative neural changes with reactive fibrosis
- oedema
- no atypia
- s100 positive
- neg for SMA, desmin, melancytic markers
Patient age:60-80s, no gender predilection
DDs:
SCHWANNOMA - Antoni A (hypocellular), antoni B(hypercellular), hyalinised blood vessels
NEUROFIBROMA - dermal, myxoid, mast cells, no proliferation of nerves
PERINEURIOMA - pooly circumscribed, dermal, myxoid, long thin cytoplasmic processes,
- neg s100 schwann cells, NFP axons
SUPERFICIAL (PILAR) LEIOMYOMA - illdefined dermal
spindled esosinophilic tumour cells
neg s100
positive for SMA, MSA, and desmin.
Hibernoma
Patient age: 20-40
PMHx: painless, slow growing mass
Anatomic location / tumour depth: thigh, upper trunk, neck, subcutaneous or intramusclular
Histologic parameters Architecture / Growth pattern: lobulated polygonal cells with granular eosinophillic cytoplasm, multivacuolated cells with numerous lipid droplets univaculolated adipocytes.
small, bland central nuclei and / or nucleoli
rare mitoses
Intratumoural vascularity: stromal vessels common
Ancillary technique:
variable s100+
spindle cell variant - CD34+
UCP1 positive in brown fat cells
Prognosis: recurrence rare
DDs: lipoblastoma, atypical lipomatous tumour, granular cell tumour, myoxid liposarcoma, rhadomyoma, chrondrod lipoma
Peripheral ossifying fibroma
reactive proliferation of fibrous tissue with mineralisation, exclusive to gingiva
associated with chronic irritation
painful or painless
nodular mass often ulcerated
Age: wide range
Anatomic location / tumour depth: exclusive to gingiva, usually interdental papilla
Histologic parameters
cellular fibroblastic stroma
mineralised component - calcification, bone, cementum
ulceration - fibropurulent surface deposit
granulation tissue
DFSP
young adults
trunk or extremities
enlarging plaque like lesion, become violaceous nodular
ill-defined infiltrative, recurrences are not uncommon
metastasis not usual except fibrosarcomatous variant
CD34 positive
translocation t(17:22) in 95%
Micro: sheets of hypercellular, uniform cells, mild nuclear hyperchromasia, rare mitoses, fibrous stroma, whorls, short fasicles, and storiform pattern, fat entrapment in honeycomb pattern.
DDx: fibrous histiocytoma - less monotonous, colllagen entrapment and lack subcutaneous invasion and neg for CD34.
Fibrosarcoma, long fasciles with herringbone pattern, more pleomorphic nuclei, necrosis
spindle cell carcinoma, melanoma. s100 and keratins.
Which type of neurofibroma is pathognomonic for neurofibromatosis type1?
Plexiform
-20-40% NF1 / von recklinghausen patients have it.
superficial location head, neck skull base
less commonly on truck and extremities
have worm-like, tortuous architecture appreciable grossly and microscopically, hypertropic nerve fasciles are commonly myxoid, often surrounded by more solid pattern of neurofibromatous prolieration, similar to diffuse type. More likely to become malignant.
cf diffuse type sheet-like, infiltrative
localised type - most common, mostly not associated with neurofibromatosis, fusiform expansion of the affected nerve, haphazard proliferation of wavy spindled cells, separated by collagen fibers, fibrous or oedematous stroma, unencapsulated, well demarcated border, no entrapment of native structures, low malignancy rate.
Describe macroscopic features of neurofibroma.
plaque like thickening, dermal, children, young adults
commonly located on head, neck and trunk
rarely malignant
Microscopic features of neurofibroma
diffuse neurofibroma ill-defined oval to spindle cells bland wavy nuclei indistinct cytoplasm variable amounts of fine collagen entraps native structures - giving infiltrative appearance foci hypertrophic appearing nerves subtle pigmentation
difference of s100 stain in schwannoma vs neurofibroma
cellular schwannoma - strong and diffuse staining, NFP and CD34 negative.
neurofibroma - patchier staining due to other admixed components. NFP highlight axons and CD34 stromal cells.
distinguish between elastofibroma desmoplastic fibroblastoma fibrolipoma spindle cell lipoma
elastofibroma - scapula, heavily collagenised, fibrous matrix, mature fat, irregular linear structures with beaded appearance - highlight with elastin stain
desmoplastic fibroblastoma - scant stellate fibroblasts, not prominent fat, but may have fat entrapment at the periphery, positive for muscle specific actin, neg for CD34, s100 and desmin
fibrolipoma - mature fat with fibrous bands, no ropey elastin, posterior neck
spindle cell lipoma - mature adipocytes, CD34 positive spindle cells, thick collagen bundles, occasional floret-type giant cells.
synovial sarcoma
monotonous, hyperchromatic spindle cells with minimal cytoplasm arranged in fascicles and sheets, overlapping nuclei, indistinct cytoplasm, staghorn thin walled vasculature (biphasic has intermixed glanular structures that stain CK, ans SS18-SSX2 is rare cf monophasic)
malignant tumours of adolescents and yound adults
located in deep soft tissues adjacent to large joints (synovium)
slow growth
positive for EMA in most cases focally/patchy - unique feature,
CD99m s100m cd57, CD56 positive in subsets.
Desmin and CD 34 are negative
monophasic - CK are positive
TLE1 diffuse strong and diffuse staining
gene translocation t(X;18)(p11;q11)
biphasic predominatly SS18-SSX1 fusion
monophasic SS18-SSX1, SSX2, or SSX4 fusion
most common site for angiosarc
cutaneous
solitary fibrous tumour
typically middle aged slow growing intermediate malignant potential well demarcated monotonous small spindled ovoid cell of moderate cellularity patternless pattern variable fibrous stroma gaping thin walled vessels
CD34 and CD99 positive,
BCL-2, SMA, EMA also positive
NAB2-STAT6 gene fusion - strong, diffuse nuclear staining
microscopic features of schwannoma
compact hypercellular Antoni A areas and myxoid hypocellular Antoni B areas
Nuclear palisading around fibrillary process (Verocay bodies) is often seen in cellular areas
Large, irregularly spaced hyalinised vessels are most prominent in Antoni B areas
Cells are narrow, elongated and wavy with tapered ends interspersed with collagen fibers
Tumor cells have ill defined cytoplasm, dense chromatin
Often displays degenerative nuclear atypia (ancient change)
strong diffuse s100 positivity
features of dermatofibrosarcoma protuberans
include immuno
genetic alteration
sheets of hypercellular uniform cells mild nuclear hyperchromasia rare mitotic activity mildly fibrous stroma whorled, fascicular, storiform architecture infiltrative growth fat entrapment - honey comb apearance
CD34 positive
t(17;22) in 95% cases, also present in fibroblastoma
fusion of COL1A1 and PDGFB
fusion gene product render tumour susceptible to tyrosine kinase imatinib mesylate
defining features of each type of neurofibromas
diffuse - well circumscribed, mast cell
localised - ill defined, mast cell, pseudomeissnerian bodies - individual or aggregates eosinophilic fibrillary clusters
plexiform - defined growth pattern, mixed nodular serpentine appearance,
