Spindle Cell Tumours Of adults Flashcards
Nonmesenchymal Spindle Cell Neoplasms
Spindle cell carcinoma (sarcomatoid carcinoma, spindle cell SCC)
Spindle cell/desmoplastic melanoma
Spindle cell/desmoplastic mesothelioma
Paraganglioma
Gliosarcoma (metastasis)
Extracranial meningioma
Myeloid sarcoma (extramedullary myeloid tumor)
Interdigitating dendritic cell sarcoma
Mast cell neoplasms (systemic mastocytosis, mastocytoma, mast cell sarcoma)
Preferential location of pseudosarcomatous myofibroblastic proliferation
urinary tract
preferential location of intranodal palisaded myofibroblastoma
inguinal lymph nodes
Preferential location fibroma of tendon sheath
hand and foot
Preferential location nuchal fibroma
back of neck
Preferential location elastofibroma
scapular area
Preferential location solitary circumscribed neuroma
face
Preferential location spindle cell lipoma
upperback, shoulder, neck
Preferential location superficial fibromatoses
palmar, plantar, and penile areas
Preferential location GIST
intraabdominal
Preferential location dedifferentiated liposarcoma
retroperitoneum, paratesticular
Preferential location spindle cell angiosarcoma
head and neck - especially face and scalp
Preferential location spindle cell rhabdomyosarcoma
paratesticular, head and neck
Preferential location biphenotypic sinonasal sarcoma
nasal cavity and paranasal sinuses
Mesenchymal spindle cell tumours
nodular fasciitis
pseudosarcomatous myofibroblastic proliferation
Nodular fasciitis
Patient age:
PMHx
Anatomic location / tumour depth:
Histologic parameters Architecture / Growth pattern: ECM: Intratumoural vascularity: Tumour necrosis: Cytomorphology: shape, cytoplasm, nuclear features, atypia Mitotic activity: Ancillary technique:
Prognosis
DDs:
Key points:
- rapid growth
- young to middle age
- forearm, head and neck
- rare in skin, joints, and blood vessels
- initially highly cellular then hypocellular and fibrotic
- myxoid stroma, extravasated RBC, tissue culture-like
Patient age: 20-40yo, no gender predilection
PMHx: 10-20% trauma, painful, develops rapidly over 4-8 weeks.
Anatomic location / tumour depth: wide, but mostly upper extremities 50%, head neck in children, infrequent in hand and feet, 10% intramusclular, but intraarticular, intravascular, intradermal, parosteal, cranial.
Histologic parameters
Architecture / Growth pattern: well circumscribed, less than 3cm,
In the subcutis, grow along fibrous septa, dissecting the adipose tissue, center around superficial aponeurosis. Variably cellular, consisting of fibroblasts and myofibroblasts arranged in short irregular fasciles, sometimes vague storiform pattern, loose textured myxoid matrix (feathery patters) or collagenous stroma.
centre of lesion can be hypocellular, giving zonal appearance,
Long standing lesions are less cellular, and more fibrotic, hyalinised fibrosis arranged in dense, refractile, keloid -like collagen bands
10% cases contain prominent osteoclast-like MNGC.
ECM: loose myxoid or collagenous, surrounded by inflammatory elements, mucin pooling, cystic change, interstitial haemorrhage, intralesional histiocytes are common.
Intratumoural vascularity: centripetally oriented capillaries.
Tumour necrosis: no
Cytomorphology: shape, cytoplasm, nuclear features,
Plump abundant eosinophilic fibrillary cytoplasm, resembling cells in tissue culture or granulation tissue.
Nuclei: vesicular, single and often prominent
Mitotic activity: numerous and typical
Ancillary technique:
myofibroblasts are strongly and diffusely positive for smooth muscle actin, muscle specific actin (clone HHF35), and calponin.
Negative for:
Desmin is observed in a few scattered cells
caldesmon, s100, cd34, beta-catenin
visceral lesion are positive for keratins,
histiocytes and osteoclast like giant cells CD68 and other histiocyte markers
Ki67- high proliferative activity
ganglion-like cells are negative for muscle markers.
molecular: clonal proliferation - rearrangements of USP6 locus at 17p13 in 90% of cases, MYH9-USP6 gene fusion detected in 65% of cases, resulting in overexpression of USP6 oncoprotein, similar to aneurysmal bone cyst.
DD - sarcomas, but NF grow fast, small, subcut, no enlarged or hyperchromatic nuclei, no necrosis, atypical mitotic figures.
myxofibrosarc - usually older, multinodular, alternating cellular and myxoid areas, enlarged hyperchromatic nuclei
DFSP - positive for CD34, neg for SMA
MPNST positive for s100, GFAP, sox 10,
LG fibromyxoid sarc - positive for MUC4, EMA and neg for SMA
Prognosis: benign, self-limiting. Local recurrences rare. Spont regression can occur.
