SOFT TISSUE Flashcards by Mariana Adjemian

Features of calcifying aponeurotic fibroma (page 1814 Rosai)

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

How well did you know this?

Not at all

Perfectly

Features of fibroma of Tendon Sheath (page 1815 Rosai)

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 -.

How well did you know this?

Not at all

Perfectly

Features of Collagenous fibroma/ desmoplastic fibroblastoma (page 1815 Rosai)

Adults. In subcutis or intramuscular. Anywhere in the body.
Hypocellular. Stellate & spindled fibroblasts in collagenous matrix +/- myxoid areas.
IHC: SMA+, Desmin -.

How well did you know this?

Not at all

Perfectly

Features of Nuchal type fibroma and Gardner fibroma (page 1816 Rosai)

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).

How well did you know this?

Not at all

Perfectly

Features of Superficial Acral Fibromyxoma (page 1816 Rosai)

All ages.
Fingers and toes.
Spindle to stellate cells in fibromyxoid/myxoid stroma.
IHC: CD34+.

How well did you know this?

Not at all

Perfectly

Features of Fibrous Hamartoma of Infancy (page 1817 Rosai)

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 -.

How well did you know this?

Not at all

Perfectly

Features of Angiolipoma (page 1850 Rosai)

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.

How well did you know this?

Not at all

Perfectly

Features of Desmoid-type Fibromatosis (page 1823 Rosai)

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.

How well did you know this?

Not at all

Perfectly

Features of DF/ Benign fibrous histiocytoma

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.

How well did you know this?

Not at all

Perfectly

Features of Dermal Nerve Sheath Myxoma

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-)

How well did you know this?

Not at all

Perfectly

Features of kaposiform Haemangioendothelioma

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 -.

How well did you know this?

Not at all

Perfectly

Reactive vascular proliferations (4)

Papillary endothelial hyperplasia
Pyogenic granuloma/lobular capillary haemangioma
Bacillary Angiomatosis
Glomeruloid Haemangioma

How well did you know this?

Not at all

Perfectly

Features of Papillary endothelial hyperplasia (PEH)

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.

How well did you know this?

Not at all

Perfectly

Features of Pyogenic granuloma (lobular capillary haemangioma)

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).

How well did you know this?

Not at all

Perfectly

Features of Nodular fasciitis

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).

How well did you know this?

Not at all

Perfectly

Spontaneously painful nodules of skin and soft tissues (5)

Study These Flashcards

Leiomyoma
Traumatic neuroma
Glomus tumour
Eccrine spiradenoma
Angiolipoma

Features of Elastofibroma

Study These Flashcards

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 +.

Features of Myositis Ossificans

Study These Flashcards

Young adults, extremities.
Hx of trauma (>50% cases).
Triphasic pattern/ zonation:
Center: Reactive fibroblasts (Nodular fasciits-like)
Intermediate: Osteoid
Periphery: Mature lamellar bone

Features of Proliferative fasciits and Proliferative myositis

Study These Flashcards

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 +.

Features of superficial fibromatosis

Study These Flashcards

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 +.

Features of solitary fibrous tumour (SFT)

Study These Flashcards

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 +.

Features of inflammatory myofibroblastic tumour (IMT)

Study These Flashcards

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).

Features of Dermatofibrosarcoma protuberans (DFSP)

Study These Flashcards

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.

Features of adult fibrosarcoma

Study These Flashcards

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 +.

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%).

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.

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.

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.

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.

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.

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.

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).

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 +.

SOFT TISSUE Flashcards

(33 cards)