SOFT TISSUE Flashcards
(33 cards)
1
Q
Features of calcifying aponeurotic fibroma (page 1814 Rosai)
A
- Hands/wrists, child or adolescent.
- Infiltrative lesion with spotty calcification.
- Bland spindle to round cells, indistinct cytoplasm in dense fibrous stroma.
- Cartwheel, linear or whorled pattern. Cells radiate out from calcification.
- Scarce mitosis.
- Can have MN giant cells.
- IHC: SMA +/-, CD68 +/-, S100 +/-, CD99 +/-.
- DD: Rheumatoid nodule
Schwannoma
Soft tissue chondroma
Fibromatosis
2
Q
Features of fibroma of Tendon Sheath (page 1815 Rosai)
A
- Attached to tendon or tendon sheath, lobulated.
- Hypocellular, ++ collagenous.
- Spindle to stellate cells, +/- bizarre cells.
- Dilated, slit like channels at the periphery
- IHC: SMA +, Desmin -.
3
Q
Features of Collagenous fibroma/ desmoplastic fibroblastoma (page 1815 Rosai)
A
- Adults. In subcutis or intramuscular. Anywhere in the body.
- Hypocellular. Stellate & spindled fibroblasts in collagenous matrix +/- myxoid areas.
- IHC: SMA+, Desmin -.
4
Q
Features of Nuchal type fibroma and Gardner fibroma (page 1816 Rosai)
A
NUCHAL TYPE FIBROMA:
- Posterior neck.
- Hypocellular bundles of thick collagen.
- Entrapped adipose tissue & traumatic neuroma-like structures.
GARDNER FIBROMA:
- Same as above but in back/paraspinal region and no entrapped nerves.
- First decade of life, associated with FAP/Gardner syndrome.
- IHC: CD34 +, CD99 +, B-catenin + (nuclear).
5
Q
Features of Superficial Acral Fibromyxoma (page 1816 Rosai)
A
- All ages.
- Fingers and toes.
- Spindle to stellate cells in fibromyxoid/myxoid stroma.
- IHC: CD34+.
6
Q
Features of Fibrous Hamartoma of Infancy (page 1817 Rosai)
A
- First 2 decades of life, M>F.
- Axilla, shoulder, upper arm.
- Organoid pattern with 3 different tissues:
#Spindle cells: Fibroblasts/myofibroblasts in a collagenous background.
#Mature adipose tissue.
#Inmature cells in a whirling pattern resembling primitive mesenchyme - IHC: SMA+ in spidle cell area, Desmin -.
7
Q
Features of Angiolipoma (page 1850 Rosai)
A
- After puberty, painful lesion.
- Well circumscribed in subcutis, can be multiple.
- Trunk and extremities.
- Admixture of blood vessels and mature adipose tissue.
- Hyaline thrombi important diagnostic sign.
- Cellular angiolipoma confused with Kaposi sarcoma or angiosarcoma.
8
Q
Features of Desmoid-type Fibromatosis (page 1823 Rosai)
A
- Lesions are intimately associated with skeletal muscles and their aponeurosis. Common in abdominal wall in women during or following pregnancy but also in men & other locations: shoulder girdle, chest wall, H &N, mesentery, thigh.
- Proliferation of well differentiated fibroblasts/myofibroblasts arranged in fascicles.
- Abundant collagen b/w cells. +/- keloid-like collagen.
- Infiltrative pattern of growth.
- Lack of cytologic features of malignancy.
- Thick walled +/- ectatic vessels sharply outlined from the surrounding tissue.
- Low or absent mitotic activity.
- Perivascular lymphocytic infiltrate at the advancing edge of the lesion.
- Aggressive clinical behaviour: recurrences (no mets).
- IHC: B-catenin +(nuclear), SMA+, Desmin + Calponin+/-
CD34 -
MOLECULAR: Activating mutations of CTNNB1 (encoding B-catenin), leading to nuclear expression of B-catenin. In cases assoc w Gardner sdme, there is a germline mutation of the APC gene (5q22). Same end result as both APC and B-catenin are components of the Wnt signaling pathway.
9
Q
Features of DF/ Benign fibrous histiocytoma
A
- Extremities most common.
- Spindle cell lesion centred in the upper dermis, but it can involve deep dermis and even extend to subcutis.
- Cellular fibrohistiocytic proliferation with collagen deposition. Histiocytes can be foamy or hemosiderin laden or they can acquire the features of Touton giant cells.
- Cells arranged in fascicles, can have storiform pattern (less so than DFSP).
- Fine vascular network.
- Collagen entrapment at lateral edge of lesion.
- Hyperplasia of overlying epidermis: +/- proliferation of hair germ like structures in the basal layer (follicular induction), rarely a BCC develops.
- IHC: Factor XIIIa +, CD34 - (reverse for DFSP).
Also SMA, Desmin, CD68 usually +. - Variants:
- Haemorrhagic/aneurysmal: Large cystic spaces full of blood.
- Prominent palisading (simil peripheral nerve).
- Myxoid change.
- Epithelioid cell DF (large, angulated cells).
- Granular/Lipidized/clear/signet ring/balloon cells.
- Marked focal atypia ‘Monster cells’.
- Diffuse eosinophilic infiltrate.
- Lichenoid, erosive, and ulcerated features.
10
Q
Features of Dermal Nerve Sheath Myxoma
A
- Distal extremities, particularly the fingers.
- Multinodular lesion with a fibrous border, distinct fascicular or plexiform arrangement.
- Reminiscent of myxoma but plumper, epithelial-like cells.
- IHC: S100+
(Different to neurothekeoma, S100-)
11
Q
Features of kaposiform Haemangioendothelioma
A
- Retroperitoneum or deep soft tissue of the extremities in children (50% during the 1st year of life).
- Can be associated with consumption coagulopathy and thrombocytopenia. Also with lymphangiomatosis.
- Micro:
- Tumor nodules surrounded by a desmoplastic stroma. The nodules show areas that resemble capillary hemangioma, whereas other areas resemble Kaposi sarcoma.
- Glomeruloid structures are a characteristic feature.
- Thin-walled lymphatic vessels are often seen at the periphery of the tumour nodules.
- IHC:
CD31/CD34 + (in glomeruloid like areas), D2-40+ (in Kaposi-like areas)
HHV8 -, GLUT 1 -.
12
Q
Reactive vascular proliferations (4)
A
- Papillary endothelial hyperplasia
- Pyogenic granuloma/lobular capillary haemangioma
- Bacillary Angiomatosis
- Glomeruloid Haemangioma
13
Q
Features of Papillary endothelial hyperplasia (PEH)
A
- Can be a reactive proliferation as a result of trauma or superimposed on a pre-existing benign vascular lesion.
- Micro:
- Usually begins within a thrombosed blood vessel with ingrowth of endothelial cells into the thrombus, forming pseudopapilla. These are lined by a single layer of plump, normochromatic endothelial cells.
- Endothelial proliferation may give the appearance of interanastomosing vascular channels, simulating angiosarcoma.
14
Q
Features of Pyogenic granuloma (lobular capillary haemangioma)
A
- Occur in mucosa (mouth) and skin. Rapid growth followed by stabilization +/- regression.
- Micro:
- Circumscribed, small polypoid lesion often surrounded by an epidermal collarette.
- Lobular architecture with central larger vessels and peripheral aggregates of well formed capillaries.
- Mixed acute and chronic inflammatory infiltrate.
- Mitosis++
- Note: Areas similar to PG can be found at the surface of any ulcerated lesion (eg SCC).
15
Q
Features of Nodular fasciitis
A
- Young adults. Rapidly growing mass trunk/UL/Neck. +/- Hx of trauma.
- Deep dermis/ subcutis.
- Well circumscribed (usually) & cellular.
- ‘Tissue culture’ growth: fascicles of plump spindle cells in a loose, feathery collagenous stroma with areas of myxoid or microcystic change.
- Mitosis++, RBC extravasation, lymphocytes.
- IHC: SMA+
- Molecular: t (17,22). MYH9- USP6 fusion ( FISH).
16
Q
Spontaneously painful nodules of skin and soft tissues (5)
A
Leiomyoma Traumatic neuroma Glomus tumour Eccrine spiradenoma Angiolipoma
17
Q
Features of Elastofibroma
A
- Subscapular region. Elderly patients.
- Hx of repetitive manual labour.
- Thickened basophilic elastic fibers forming refractile cylinders amongst fibroblasts and collagen bundles (spaghetti & meatballs look).
- Entrapped adipose tissue common.
- IHC: Elastin stain +.
18
Q
Features of Myositis Ossificans
A
- Young adults, extremities.
- Hx of trauma (>50% cases).
- Triphasic pattern/ zonation:
- Center: Reactive fibroblasts (Nodular fasciits-like)
- Intermediate: Osteoid
- Periphery: Mature lamellar bone
19
Q
Features of Proliferative fasciits and Proliferative myositis
A
- Adults, average 50 years old.
- In subcutis, along fibrous septae (PF) or intramuscular (PM).
- More ill defined than nodular fasciits.
- Spindle cells & scattered ganglion-like cells (large vesicular nuclei, prominent nucleoli and eosinophilic cytoplasm).
- IHC: ganglion-like cells are SMA -, Vimentin +.
20
Q
Features of superficial fibromatosis
A
Palmar Fibromatosis (Dupuytren’s): Only adults, bilateral in ETOH.
Plantar Fibromatosis: Children and adults. Often multinodular.
- Proliferative phase: Fascicles of bland spindle cells in a nodular pattern. +/- giant cells in plantar lesions, +/- mitosis.
- Involutional phase: Paucicellular, dense collagen.
- IHC: SMA +.
21
Q
Features of solitary fibrous tumour (SFT)
A
- Wide age range. Slow growing painless mass.
- Common in pleura, but any location.
- Well circumscribed.
- Monotonous ovoid to spindle cells in a “paternless pattern” (arranged haphazardly) associated with wire-like collagen.
- Staghorn/HPC vessels.
- Hyper/hypocellular areas.
- Low mitosis (3/10 HPF).
- IHC: CD34, STAT6, CD99, BCL2 +.
22
Q
Features of inflammatory myofibroblastic tumour (IMT)
A
- Children and adults, any site but common in lung, mesentery and retroperitoneum.
- Spindle cells in variable patterns, admixed with Lo and plasma cells.
- Myxoid or collagenous background, hyper/hypocellular areas.
- Mitosis common.
- IHC: SMA +, ALK + (50% cases).
23
Q
Features of Dermatofibrosarcoma protuberans (DFSP)
A
- Young adults and children.
- Trunk and proximal extremities.
- Diffuse, deep dermis to subcutis.
- Uniform, bland spindle cells in a storiform pattern.
- Tumour cells infiltrate around adnexa and into subcutis in a ‘lace-like’ pattern (‘honeycomb’ appearance of fat).
- Few mitosis.
- IHC: CD34+.
- Molecular: fusion COL1A1 & PDGFB.
24
Q
Features of adult fibrosarcoma
A
- Rare malignant tumour of fibroblasts with a herringbone architecture (long fascicles intersecting at acute angles) and variable collagen. Mitosis present.
- No pleomorphism, no giant cells.
- Diagnosis of exclusion.
- DD: Fibromatosis, SS, MPNST, UPS.
- IHC: SMA +.
25
Features of low grade fibromyxoid sarcoma (LGFMS)
- Young, middle aged adults.
- Thigh > trunk.
- Low to moderate cellularity.
- Deceptively bland spindle cells deposited in collagenous and myxoid background (fibroid > myxoid).
- Prominent vessels with perivascular hypercellularity.
- +/- prominent rosettes, whorled pattern.
- IHC: MUC4+, EMA+.
- Molecular: t(7,16) with FUS-CREB3L2 fusion (95%) or FUS-CREB3L1 (5%).
26
Features of Myxofibrosarcoma (low grade)
(myxoid subtype of UPS, formerly myxoid MFH)
- Elderly. Extremities.
- Dermis/subcutis or deeper.
- Multinodular tumour composed of pleomorphic spindle cells in a myxoid (>than fibroid) background.
- Curvilinear vessels with condensation of cells around vessels.
- Infiltrative, sends out long tentacles.
- 'Pseudolipoblasts' common.
- Higher grade: More cellular, atypical mitosis, necrosis or haemorrhage.
- IHC: Nil specific. Vimentin, CD34 +/-.
- Molecular: complex karyotypes.
27
Features of Sclerosing Epithelioid Fibrosarcoma
(Variant of fibrosarcoma)
- Small round/ovoid cells with scanty clear cytoplasm embedded in densely hialinized stroma.
- Often single file pattern (DD with Carcinoma).
- Like LGFMS: MUC4+ and can have FUS translocation.
28
Features of Tenosynovial Giant Cell Tumour, Localized type
- Adults, 40s to 60s. F>M.
- Distal extremities (hands > toes).
- Lobulated with capsule.
- Small and large mononuclear cells, MNG cells, xanthoma cells, inflammatory cells & haemosiderin in a collagenous background.
- Cleft like spaces at periphery.
- IHC: CD45, CD68, CD123 +.
- Molecular: Re-arrangement of CSF1 gene.
29
Features of Giant Cell Tumour of Tendon Sheath
(same as PVNS: Pigmented Villonodular Synovitis)
- Intra-articular location.
- Less common than localized. Age: 50s.
- Knee > ankle > foot.
- Similar hstology as localized type but infiltrates surrounding tissues.
30
Features of Giant Cell Tumour of the Soft Tissues
- All ages, hand or arm.
- Multiple nodules infiltrating surrounding soft tissues.
- Bland mononuclear cells, MNG cells (osteoclasts) & short spindle cells.
- Mitosis =/-.
- Similar histo but different entity to GCT of bone.
31
Features of Hibernoma
- Interscapular area, axilla and thigh. Also mediastinum and retroperitoneum.
- Gross: brown cut surface.
- Organoid arrangement of large cells with centrally located nuclei and cytoplasm with multiple small vacuoles.
- Can be hybrid with lipoma.
32
Features of Lipoblastoma
- Infants/children < 5yo.
- Proximal extremities.
- 'Lipoblastoma' if well circumscribed, 'lipoblastomatosis' if ill defined.
- Lobulated, mature adipocytes and lipoblasts in myxoid stroma.
- Plexiform vascular pattern.
- Molecular: Re-arrangement of PLAG-1 (pleomorphic adenoma gene).
(In contrast: myxoid liposarcoma has DDT3 gene translocation).
33
Features of Lipoma
- Usually upper half of body.
- 5th-6th decades of life, most are subcutaneous (unlike liposarcomas).
- Multiple lipomas: seen in NF or MEN syndrome.
- Usually encapsulated, except in deep locations.
- Mature adipose tissue, no cellular atypia.
- +/- fat necrosis, infarct, calcification or metaplastic cartilage or bone.
- Pitfall: histiocytes associated with fat necrosis resemble lipoblasts.
- IHC: S100+, calretinin +.
