Soft Tissue Tumour

Fatty Tissue Tumour

Lipoma Liposarcoma

Nature Benign Malignant

Age 40-70 40-70

Site Subcutaenous

Upper back

Shoulder/ Back

Proximal extremities

Retroperitoneum

Paratesticular

Clinical Soft, Mobile, Painless (except angiolipoma) Painless, Deep seated

Subtypes Fibrolipoma, Angiolipoma, Myelolipoma, Spindle cell lipoma, Pleomorphic

lipoma

Well differentiated, Myxoid, Round cell, Pleomorphic, Dedi ferentiated

X-ray Well-circumscribed, Homogenous, Similar density as fat Lobulated with mass – contain strand of soft tissue slightly dense

HPE Lobules of mature adipocytes

Fibrous septae

Heterogenous population of adipocytes

Lipoblasts

Rx Complete resection Complete resection

Prognosis Good (except intramuscular type) Depend on location, type

Lipoma

Neoplastic adipocytes –

indistinguishable from normal

adipocytes

Spindle cell lipoma

Proliferation of adipocytes

Disorganized bands of collagen –

contain spindle cells

Liposarcoma

Large mass lesion

Yellowish, like adipose tissue

Well-differentiated

Liposarcoma

Adipocytes

Pleomorphism of neoplastic cells

(lipoblasts)

Pleomorphic lipoma

Floret cells (large pleomorphic cells

with nuclei around cell periphery)

Cellular angiolipoma

Well-circumscribed tumor

Compose d of vascular proliferation

Scattered fat cells

Thrombi (in blood filled spaces)

Liposarcoma Large bizarre lipoblasts

Liposarcoma

Well-differentiated atypical lipoma

Fibrous septa (cellular septa)

Liposarcoma

Well-differentiated atypical lipoma

Pleomorphic nuclei scattered among

fat cells

Myxoid, Liposarcoma

Branching capillary network

Small cells of myxoid liposarcoma

Lipoblasts

Lymphangioma-like cystic

degeneration

Pleomorphic, Li posarcoma

Cells with multiple grapelike vacuoles

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Smooth Muscle Tumour

Leiomyoma Leiomyosarcoma

Age 30-50 > 20

Sites Uterus

Skin, nipples, scrotum, labia

Intestine, less in deep soft tissue

Cutaneous (extremities & trunk)

Large blood vessels (IVC) & deep soft tissue

Uterus

Signs &

Symptoms

Painless soft tissue swelling

Painful in pilar leiomyoma

Intestinal obstruction & urinary symptoms

Soft tissue swelling

Mass effect : obstruction

Size 1-2 cm (e xcept uterus) > 5 cm

HPE Circumscribed

Bland smooth muscle

Whorl pattern

< 1 mitosis/ 10 HPF (high power field)

Degenerative changes

Interweaving fascicles of pleomorphic spindle cells

↑ mitosis

Necrosis

Sarcomatous like MFH (malignant fibrous histiocytoma)

IM Actin + Desmin + Actin + Desmin +

Prognosis Good Depend on size, location, grade

Retroperitoneum - incomplete excision

Uterine fibroids/ uterine leiomyoma

Leiomyoma

Cells do not vary greatly in size &

shape

Resemble normal smooth muscle

cells

Leiomyosarcoma

Alternating fascicle pattern

Blunt-edged nuclei

Minor pleomorphism present

Leiomyoma

Blunt-ended elongated nuclei

(smooth muscle proliferation) Bizarre leiomyoma

Enlarged pleomorphic nuclei

Non-mitotic

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Skeletal Muscle Tumour

Rhabdomyoma Rhabdomyosarcoma (RMS)

Cardiac rhabomyoma (hemartomatous)

1. Rare

2. < 5y/o

3. Frequently associated with tuberous sclerosis

4. HPE – large, polygonal cells with glycogen

vacuoles

Common soft tissue sarcoma – children, adolescent

Cytogenic abnormalities

Diagnostic cell = rhabdomyoblast

Adult rhadomyoma

1. > 40 y/o

2. Exclusively in Head & Neck region – eg.

Oropharynx

Sites

1. Head & Neck

2. Genitourinary tract

3. Extremities

Genital rhabdomyoma

1. 20-40 y/o

2. Polypoidal lesion (spindle cell) at vagina, vulva,

cervix

Histological subtypes

Embryonal RMS Alveolar RMS Pleomorphic/ anaplastic RMS

Conventional

Botyoid (sarcoma botryoides)

Spindle cell

Infant & children Adolescent Adult

1. Head & Neck, GUS,

retroperitoneum

2. Bladder, vagina, rectum,

nasal cavity, nasopharynx

3. Paratesticular

Extremities, paranasal sinuses,

retroperitoneum

Extremities

Spindle cells

Cross-striations

Rhabdomyoblast

Primitive cells

Cambium layers

Abundant collagen

Alveolar-like spaces

Fibrous septae

Cross-striation

Rhabdomyoblast

Large, pleomorphic

Multinucleated

↑ mitosis

Rhabdomyosarcoma (Embryonal

type)

Round cells with small oval nuclei

Scanty eosinophilic cytoplasm

Eccentric placement of nucleus in

cytoplasm

Rhabdomyosarcoma (Alveolar

type) Tumor cells – grip fibrous septa

around alveoli

Large pleomorphic cells with

abundant cytoplasm

Rhabdomyosarcoma (Botryoid

type) Orbital conjunctiva

Dense aggregation of cells below

epithelium

Rhabdomyosarcoma (Botyroid type)

Cambium layer

Loose texture

Differenting strap cells

Rhabdomyoma

(genital type) Fibrous tissue

Spindling groups of

cells

Long cytoplasmic

extensions with

parallel sides

IM – Vimentin, Desmin, Myogenin

Treatment – Surgery, Chemotherapy with or without radiotherapy

Prognosis – Staging, Age, Histological subtypes (Botryoid > Embryonal > Pleomorphic > Alveolar)

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Fibrous Tissue Tumour

Fibroma Fibromatosis Fibrosarcoma

Rare Superficial Deep (Desmoid tumor)

Palmar

Plantar

Penile

Extra-abdominal

shoulder, chest wall,

back, thigh

Abdominal

anterior abdominal wall

Intra-abdominal

mesentery, pelvic wall

Male ↑ Female ↑

Benign

Do not progress

Agressive locally

Frequenty recur but

never metastasize

Fibroblasts

Collagen deposit

Fibroblasts & collagen

Mitosis infrequent

Fibromatosis Fibroblasts proliferate on collagen

Cytoplasm is inapparent, but visible if cut en face

(center)

Rare

Fibroma-thecoma in ovary Diagnosis by exclusion

Renal fibroma – hamartoma Sites

Retroperitoneum, thigh, knee, distal extremities

Gross

Uncapsulated, soft, infiltrative with areas of

hemorrhage & necrosis

HPE

Fascicles of spindle cells

Herringbone pattern

Frequent mitosis & necrosis

Prognosis Aggressive

50% recur

25% metastasize

Fibrosarcoma

Fascicles of spindle cells

Lesion is cellular

Fibrosarcoma Herringbone pattern

Differential diagnosis – synovial sarcoma, malignant

peripheral nerve sheath tumor

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Fibrohistiocytic tumour

BFH (Benign fibrohistiocytic tumour) DFP (Dermatofibrosarcoma protuberans) MFH (Malignant fibrohistiocytic tumour)

Benign Borderline Malignant

Dermatofibroma Common pathway for ST sarcoma progression

Age 20-50 20-50 > 50

Sex Male ↑ Male = Female Male ↑

Sites Skin

Lower limb

Head & Neck

Trunk

Groin

Lower Limb

Head & Neck

Proximal extremities

Retroperitoneum

Signs &

Symptoms

Slow growing dermal / Soft tissue (ST) mass Exophytic

Multinodular painless growth

Large mass

Sometimes with pain

Gross Fairly circumscribed nodule/ mass Poorly circumscribed

with entrapped skin adnexae & fat

5-20 cm pse udo-capsule hemorrhage & necrosis

Sub-types - Classical

Bednar tumour

Storiform/ Pleo

Myxoid

Inflammatory

Giant cell

Angiomatoid

Histo Spindle cells

Infiltrative margin

Foam cells, hemosiderin, giant cells, epidermal

hyperplasia

Spindle cells

Infiltrative margin

Prominent storiform pattern

Mitosis <5/10 HPF

Depends on subtypes

Rx Simple excision Wide surgical resection Wide surgical resection

Prognosis Good Recurrence (50% )

Metastasis (5-15%)

Aggressive (except angiomatoid)

Metastasis (30-50%)

60% - 5 year survival rate (YSR)

Benign fibrous histiocytoma

Hyperplastic epidermis

Dermal spindle cell lesion – contain lakes of

blood

No endothelial lining of lakes

Dermatofibrosarcoma protuberans

Cartwheel/ storiform pattern

(without pleomorphism)

Thin nuclei, lack of perceptible cell borders, overall

tight quality of pattern

Malignant fibrous histiocytoma (Medium power)

Storiform/ pleomorphic

Pleomorphic nuclei scattered among smaller cells

Vague storiform pattern

Small fibrous histiocytomas Cartwheel/ storiform cells

Lack plaquelike growth in dermis/ subcutaneous fat

Malignant fibrous histiocytoma (High power)

Bizarre nuclei in huge cells found

Inflammatory infiltrate

Spindle cells – irregular nuclear shapes, lack well-

defined cell borders

Malignant fibrous histiocytoma (angiomatoid)

Dark cuff of lymphoid cells complete with

germinal center

Lighter tumour nodules proliferate

Malignant fibrous histiocytoma (inflammatory) Malignant nuclei are larger & vesicular (not bizarre)

Sea of neutrophils & other inflammatory cells

Malignant fibrous histiocytoma (Giant cell)

Osteoclast-like giant cells

Malignant tumour giant cells with enlarged nuclei

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Blood vessel tumour

Hemangioma Hemangioendothelioma Angiosarcoma

Nature Benign Borderline Malignant

Age Infant & children > 40 > 40

Sites Skin of Head & Neck

Liver

ST of extremities

Large veins

Skin of Head & Neck

Skin of Head & Neck

Breast, liver, spleen

ST of extremities

HPE Benign endothelial cells

In lobules

Proliferating endothelial cells

Cytoplasmic vacuoles containing RBC

Malignant pleomorphic cells

Anastomosing blood vessels

Prognosis Good Variable

Majority cured by excision

Up to 40% recur

Up to 30% metastasize

Very poor

Margin clearance difficult

60% recur

50% metastasize

Capillary Cavernous Lobular capillary

Infancy, early

childhood

Infant

Children

Any age

Female ↑ Female ↑ F=M

Skin &

subcutaneous of

Head & Neck

Skin &

subcutaneous

Deep ST

Liver

Gingiva, fingers,

lip & face

Lobules of small

size vessel

Central “feeder”

vessel

Large blood-

filled vessels

Thrombi &

calcification

As capillary type

Inflammation &

ulcer

Spontaneous

regression

No spontaneous

regression

No spontaneous

regression

Grade 2 Hemangioendothelioma Vessel-forming growth pattern

Blood-filled spaces

Angiosarcoma

Collagen as scaffold for endothelial cells

Too many cells line anastomosing spaces

Atypia

Lobular capillary hemangioma (pyogenic granuloma)

(Medium power)

Lobules are sharply demarcated by fibrous septa –

hypercellular & lack spindy stream of cells in Kaposi disease

Spindle cell hemangioendothelioma

Vacuolated endothelial cells

Lining blood-filled channels

Lobular capillary hemangioma (pyogenic granuloma)

(High power)

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Peripheral Nerve Tumour

Neurofibroma Schwannoma (neurilemmoma) Malignant peripheral nerve shealth tumour (MPNST)

20-40 y/o. 5-30 y/o (Diffuse)

Childhood (plexifor m)

20-50 y/o 20-50 y/o

Male = Female (but Male ↑ in neurofibromatosis)

Solitary

Diffuse

Plexiform

Soliary

Multiple (3%)

= Neurofibrosarcoma

= Malignant schwannoma

Any sites (especially Head & Neck) Extremities & Head & Neck

Cellular schwannoma – mediastinum, retroperitoneal,

pelvis

Slow growing painless skin lesions

Plaque-like in diffuse type

Tortous, worm-like nerve

Elephantiasis neuromatosa

Slow growing tumour

Pain with neurologic symptoms

Headache, nasal obstruction, epistaxis, otitis media

Hearing loss + tinnitus

Soft tissue mass with/ without pain

Long sweeping fascicles & herring bone patterns

Hypocellular myxoid areas (CT fibrosarcoma)

Nuclear palisading

Geographical necrosis

Metaplastic changes (eg. Bone)

Others – rosettes, glands formation, perivascular

condensation, neuroepithelial differentiation like

Ewing sarcoma

Epitheloid variant (CT melanoma or carcinoma)

Triton tumour (MPNST + RMS differentiation)

NF Type 1 (chromosome 17 ) NF Type 2 (chromosome 22 )

No capsule

Fusiform, plaque, plexiform

Well-circumscribed

Encapsulated

Dumbbell-shape d lesion

Spindle cell in haphazard arrangement

Hypocellular area

Mast cells

Antoni A area

Antoni B area

Verocay bodies

Hyalinized blood vessels

Cured by excision (solitary)

Recur & ↑ risk malignancy (NF)

Cured by excision Wide surgical resection

Neurofibroma

Plexiform neurofibroma

Schwannoma

Dimorphic pattern of cellular (Antoni A)

Loose myxoid (Antoni B)

Nuclear palisading (parallel rows of nuclei)

Malignant peripheral nerve sheath tumour

Mitotically active & cellular tumour

Nuclei bullet shaped

(blunt at one end, pointed at other)

Neurofibroma

Uniformly hypocellular

Slightly myxoid

Undulating fibrillar background

Spindle cell carcinoma

Nervelike whorls

Primitive Neuroectodermal tumour (PNET) (= Ewing sarcoma)

10-15 y/o

Swelling with pain & fever

Morphology

Small uniform round cells with scanty cytoplasm

Very little stroma

Rosette formation

Aggressive tumour

Treatment with resection & chemotherapy +/- radioRx

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Synovial Sarcoma

Carcinoma of soft tissue

20-40 y/o

Location

Lower > upper extremities & proximal > distal

Head & Neck, abdomen, retroperitoneum

Only 10% intra-articular

Radiographic findings

Deceptively well-circumscribed

Stippled calcifications

Mimic myositis ossificans (due to extensive calcification & metaplastic bone formation)

Pathologic findings

• Fibrous elements

o Spindle cells (monotonous, uniform) in short fasci cles

o Collagen (variable stromal)

o Alternating hypercellular & hypocellular regions

• Epithelial elements

o Gland formation

o Mucin production

• Intratumoral calcifications

• Cystic degeneration

• Metaplastic bone reaction

Subtypes Monophasic fibrous > Biphasic > Monophasic epithelial > Poorly differentiated

IM Vimentin, EMA, Cytokeratin, CD99

Treatment

Surgical resection (plus adjuvant therapy)

Risk factors for disease progression

Age > 25

Size > 5

High nuclear grade (poorly differentiated)

Necrosis > 50%

Rhabdoid morphology

↑ Tumour stage

Disease-free survival 88% in low-risk group (<25 y/o, <5cm, no poorly differentiated)

18% in high-risk group

Synovial sarcoma (Biphasic type)

Glands

Small, oval, overlapping nuclei in spindle component

Synovial sarcoma (Monophasic type)

Pericytomatous pattern

Solid areas

Synovial sarcoma (Monophasic type)

Focal cell cluster (indicate epithelial differentiation)

Synovial sarcoma (Reticulin stain)

Epithelial nesting pattern

Synovial sarcoma

Cytokeratin – glands, scattered spindle cells

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