Soft tissue (mesenchymal) tumours

Question 1

What is a neurofibroma?

Answer 1

A nerve sheath tumour caused by growth of perineural fibroblasts, schwann cells.

Question 2

How does a neurofibroma grow?

Answer 2

Slow-growing

Soft, painless lesion

Question 3

What is neurofibromatosis I?

Answer 3

An autosomally dominant genetic condition caused by mutations in the NF1 gene.

Question 4

What is NF1?

Answer 4

A tumour supressor gene that encodes for the protein neurofibromin which regulates the ras-mediated growth pathway

Question 5

What are the potential outcomes of neurofibromatosis?

Answer 5

5% of cases have malignancies:

A malignant schwannoma can form

A malignant neurofibrosarcoma can also form.

Question 6

What are the histopathological features of a neurofibroma?

Answer 6

Proliferation of all elements of peripheral nerves.

Cells have wavy nuclei.

Fibromyxoid background.

Mast cells

Question 7

How is a neurofibroma treated?

Answer 7

Excision of the lesion

Question 8

What is a neurilemmoma?

Answer 8

AKA schwannoma. A benign peripheral nerve sheath tumour composed of schwann cells.

Schwann cells normally produce the insulating myelin sheath covering peripheral nerves

Question 9

How do neurilemmomas arise?

Answer 9

Can be sporadic or genetically acquired.

Loss of function of merlin, either by direct genetic change involving NF2 gene or secondarily to merlin inactivation

Question 10

What are the histopathologic features of a neurilemmoma?

Answer 10

Well-circumscribed lesion in the Connective tissue.

The tumour is composed of different areas of different cellular densities. Shows Antoni A and B pattern

Question 11

What are the features of the antoni B pattern?

Answer 11

Loose, less cellular areas are
composed of a loose
oedematous and mucinous
stroma with fibrillar
collagen.

Question 12

What are the features of the antoni A pattern?

Answer 12

MORE CELLULAR AREAS ARE COMPOSED OF A HAPHAZARD
ARRANGEMENT OF BLAND
CELLS WITH SPINDLED AND
OVAL NUCLEI

Question 13

How is a neurilemmoma/schwannoma treated?

Answer 13

Excision of the lesion

Question 14

What is a lipoma?

Answer 14

Benign tumour of adipose tissue more common in obese people

Question 15

What are the clinical features of a lipoma?

Answer 15

Mobile, painless submucosal lesion. Yellow tinge seen if it is superficial enough.

More common in obese people but metabolism is completely independent of body fat.

Question 16

What are the histopathological features of a lipoma?

Answer 16

Lesion composed of abundant mature adipocytes arranged in lobules separated by fibrous tissue septa.

Question 17

How are lipomas treated?

Answer 17

Surgical excision

Question 18

What are haemangiomas?

Answer 18

Tumours identified by rapid endothelial cell proliferation in early infancy, commonly followed by involution
over time.

A proliferating mass of
endothelial cells and
pericytes.

Question 19

What causes haemangiomas?

Answer 19

One hypothesis postulates
that placental cells, such
as the trophoblast, may be
the cell of origin for
haemangiomas.

Question 20

What are the clinical features of haemangiomas?

Answer 20

Soft mass, smooth or lobulated, sessile or
pedunculated.

A few millimeters to several centimeters.

Pink to red / purple and tumour blanches on the
application of pressure,

Hemorrhage may occur either spontaneously or
after minor trauma.

Generally painless.

Question 21

How are haemangiomas diagnosed?

Answer 21

Doppler ultrasonography

MRI

MRI angiogram

CT angiogram

Question 22

What does haemangioma look like on Coronal contrast-enhanced T1-
weighted image (MRI T1 weighted)?

Answer 22

Coronal contrast-enhanced T1-
weighted image.
A well-rounded homogeneously
enhancing cervical mass is
associated with high-flow vessels
(signal voids) in and around the
mass.

Question 23

What do early haemangiomas look like on histology?

Answer 23

Numerous plump endothelial cells

Indistinct vascular spaces

Question 24

What do mature haemangiomas look like on histology?

Answer 24

Endothelial cells flatten,

Vascular spaces become more evident

Question 25

What do haemangiomas look like on histology during involution?

Answer 25

The vascular spaces become less prominent Replaced by fibrous connective tissue.

Question 26

How are haemangiomas treated?

Answer 26

Monitoring and Education- most haemangiomas of infancy undergo involution - 90% at age 9 yrs and normal skin is restored in 80% of patients. up to 40% of patients will show permanent changes such as atrophy, scarring, wrinkling and telengiectasis If intervention is required, oral corticosteroids are used, intralesional injection of fibrosing agents, INFα-2b, radiation, electrocoagulation, cryosurgery, laser therapy, embolisation and surgical excision

Question 27

What are the potential adverse outcomes of haemangiomas following involution?

Answer 27

Up to 40% of patients will show permanent changes such as atrophy, scarring, wrinkling and telengiectasis

Question 28

What is a fibrosarcoma?

Answer 28

Malignant tumour of | fibroblasts

Question 29

Where is a fibrosarcoma typically seen?

Answer 29

Male = female Most common between 30 - 60 years of age Uncommon in the head and neck

Question 30

What is the cause of a fibrosarcoma?

Answer 30

Not entirely understood. Several thoughts about how it arises: Idiopathic Genetically predisposing Radiation exposure Viral-induced Chemical induced. Genetic alterations?

Question 31

What are the clinical symptoms of a fibrosarcoma?

Answer 31

Pain Swelling Tooth losening Paraesthesia

Question 32

How is a fibrosarcoma diagnosed?

Answer 32

Imaging: Combined MRI and CT scans are recommended. CT scan of the chest is important to assess metastatic lesions to the lungs. Positron-emission tomography (PET) using fluorodeoxyglucose (FDG) is a functional technique that evaluates glucose utilization by the tumour. Immunohistochemistry: +ve for vimentin Fluorescence in situ hybridization (FISH)

Question 33

What are the histopathologic features of a fibrosarcoma?

Answer 33

Proliferation of fibroblasts with variable amounts of collagen and reticulin fiber formation

Question 34

How are fibrosarcomas graded?

Answer 34

Low to high; Low = spindle cells arranged in fascicles, mild nuclear pleomorphism High = atypical mitoses, intense nuclear polymorphism.

Question 35

How is a fibrosarcoma treated?

Answer 35

Surgery is the treatment of choice Radiotherapy indicated for: High grade sarcomas, positive surgical margins, lesions larger than 5 cm, and recurrent lesions Chemotherapy if unresectable or a highly aggressive lesion

Question 36

What is a kaposi sarcoma?

Answer 36

Vascular lesion of endothelial origin that develops from cells that line the blood and lymph vessels.

Question 37

What causes kaposi sarcoma?

Answer 37

Human Herpes Virus8 which reprograms the host’s blood endothelial cells to: •Resemble lymphatic endothelium, upregulating several lymphatic- associated genes •Upregulates lymphatic vessel endothelial receptor 1, podoplanin, and vascular endothelial growth factor receptor 3. Relies on some degree of immune dysfunction. HHV8 remains latent within B lymphocytes (developed a variety of mechanisms to evade the host immune system)

Question 38

What are the types of kaposi sarcoma?

Answer 38

Classic Endemic Iatrogenic immunosuppression associated (recipients of organ transplants. Affects 0.8% of renal transplant patients) AIDS - related An interplay of HHV-8 with immunologic, genetic, and environmental factors determine which type.

Question 39

Who commonly gets classic kaposi sarcoma?

Answer 39

Primarily a disease of late adult life, 70% to 90% of cases occur in men. Mostly affects individuals of Italian, Jewish, or Slavic ancestry.

Question 40

How is kaposi's sarcoma treated?

Answer 40

Depends on the clinical subtype and stage of the disease. Treating the cause of the immune system dysfunction can slow or stop the progression of kaposi’s sarcoma. AIDS-associated Kaposi sarcoma (Lesions may shrink with HAART) People with a few local lesions can often be treated with local measures such as: § radiation therapy § Cryosurgery § injection of chemotherapeutic agents Systemic chemotherapy: § vinblastine

Question 41

What is rhabdomyosarcoma?

Answer 41

Malignant neoplasm characterized by skeletal muscle differentiation. Much more common in young children.

Question 42

Who most commonly gets rhabdomyosarcoma?

Answer 42

60% of soft tissue tumours of childhood are rhabdomyosarcomas

Question 43

What causes rhabdomyosarcoma?

Answer 43

Genetic translocation producing new protein that interrupts skeletal muscle differentiation

Question 44

What are the clinical symptoms of a rhabdomyosarcoma?

Answer 44

Infiltrative mass that grows rapidly may cause: Pain Paraesthesia Facial swelling Trismus Nasal discharge

Question 45

What are the subtypes of rhabdomyosarcoma?

Answer 45

International Classification of Rhabdomyosarcoma: Superior prognosis § Botryoid § Spindle cell Intermediate prognosis § Embryonal Poor prognosis § Alveolar § Undifferentiated sarcoma

Question 46

How can rhabdomyosarcoma be diagnosed?

Answer 46

Imaging: CT and MRI scans.

Question 47

What are the histopathologic features of rhabdomyosarcoma?

Answer 47

Rhabdomyoblasts

Question 48

How is rhabdomyosarcoma treated?

Answer 48

Local surgical excision then: Multi-agent chemo (vincristine, actinomycin D, and cyclophosphamide) Postop radiotherapy (Except for localised tumors that have been completely resected at initial surgery)