Lec 9&10 covered soft tissue tumors. Lipomas are benign fatty tumors that are usually solitary, well-encapsulated masses of mature adipocytes. Liposarcomas are malignant tumors of adipocytes that typically present as large, infiltrative masses with areas of necrosis. Nodular fasciitis is a self-limited reactive lesion, while fibromatoses are locally aggressive fibroblastic proliferations. Fibrosarcomas are highly malignant fibrous tumors. Leiomyomas are benign smooth muscle tumors that can occur anywhere, while leiomyosarcomas are malignant variants. Rhabdomyosarcoma is the most common soft tissue sarcoma in children that can vary considerably in

1. Lec 9&10
Lec 9&10

2. Definition
Mesenchymal proliferations that occur in the
extraskeletal, nonepithelial tissues of the body,
excluding the viscera, coverings of the brain, and
lymphoreticular system.
- Soft tissue benign tumours outnumber malignant
Tumours 100:1
-They are aggressive if malignant

3. Histologic type Benign Malignant
Adipose Tissue Lipoma Liposarcoma
Fibrous tissue Fibromatosis
Nodular fasciitis
Fibrosarcoma
Fibrohistiocytic tumours Fibrous histiocytoma
Dermatofibroma
Malignant Fibrous
Histiocytoma?????
Skeletal Muscle Rhabdomyoma Rhabdomyosarcoma
Smooth Muscle Leiomyoma Leiomyosarcoma
Vascular Haemangioma
Lymphangioma
Angiosarcoma
Peripheral nerve Neurofibroma
Schwannoma
Malignant peripheral
nerve sheath tumour
Uncertain histogenesis Granular cell tumour Synovial Sarcoma
Alveolar soft part
sarcoma
Epithelioid sarcoma

4. CAUSES
• MOSTLY UNKNOWN
• RADIATION association
• CHEMICAL BURN association
• THERMAL BURN association
• TRAUMA association
• VIRUS association (HHV8 for Kaposi)
• GENETICS
• Parts of many SYNDROMES
• MANY TRANSLOCATIONS

6. TUMORS OF ADIPOSE TISSUE
LIPOMA
Lipomas most common soft tissue tumors.
Site: anywhere in the body subcutaneous tissues of
adults.
Clinical: slowly enlarging masses.
Most lipomas are solitary , sporadic.
Rare familial multiple lipomas.

7. TUMORS OF ADIPOSE TISSUE
LIPOMA cont….
Morphology:
Gross: soft, yellow encapsulated mass. Superficial are well
circumscribed, deep lesions be less demarcated.
Microscopically: composed of mature adipose tissue.
Variants:
- Vasculare tissue (angiolipoma) give local pain
- Smooth muscle (myolipoma)
- Bone marrow (myelolipoma of adrenal gland)
- Angiomyolipoma, containing a mixture of adipose tissue,
smooth muscle, and blood vessels. Occur in kidneys of patients
with tuberous sclerosis.
Treatment: Complete excision is usually curative.

9. Lipomas
Conventional lipomas are soft, yellow, well-
encapsulated masses of mature adipocytes; they
can vary considerably in size.

10. Lipomas
Histologically, they consist of mature white fat
cells with no pleomorphism.

11. Liposarcoma
• Liposarcomas are malignant neoplasms of adipocytes.
• AGE: They occur most commonly in the fifth and sixth
decades.
• SITE: Most liposarcomas arise in the deep soft tissues or
in visceral sites.
• The prognosis:
• is greatly influenced by the histologic subtype;
• well-differentiated types have a more favorable outlook
than do the more aggressive poorly differentiated
tumors.
• Metastasis: metastasize to lungs.

12. Liposarcoma
morphology
• Several different histologic subtypes are recognized,
• 1- Low-grade variants;
• the well-differentiated liposarcoma
• the myxoid/round cell liposarcoma, [ abundant, mucoid extracellular
matrix].
• Some well-differentiated lesions can be difficult to distinguish
histologically from lipomas,
• 2- Poorly differentiated tumors;Pleomorphic variant
• resemble various other high-grade malignancies.
• In most cases, cells indicative of fatty differentiation are present.
Such cells are known as lipoblasts; they recapitulate fetal fat cells
with cytoplasmic lipid vacuoles that scallop the nucleus

13. Liposarcoma
morphology
Large relatively well-circumscribed lesions. soft tissue mass. The
mass is uncapsulated, soft, yellow, lobulated,with marked areas
of hemorrhage and necrosis.

14. Liposarcoma
morphology

15. TUMORS AND TUMOR-LIKE
LESIONS OF FIBROUS TISSUE
• Nodular fascitis, reactive, self-limited lesion.
• Fibromatoses, aggressive local growth that may defy
surgical excision.
• Fibrosarcomas, highly malignant, recur locally, and
metastasize.

16. TUMORS OF FIBROUS TISSUE
Nodular Fascitis
Nodular fascitis is a self-limited, reactive fibroblastic
proliferation mistaken for a sarcoma.
Age: young adults.
Clinically: rapidly enlarging, painful mass of several
weeks duration.
10% to 15% of cases, a history of local trauma.
Site: Any part of the body, most common in the
upper extremities(Forearm) and trunk.
Treatment: excision

17. TUMORS OF FIBROUS TISSUE
Nodular Fascitis
Morphology
Grossly: unencapsulated lesion in the subcutaneous
tissue, muscle, or deep fascia. Superficial locations, well
circumscribed, nodular with poorly defined margins .
Microscopically, composed of immature
fibroblastic cells with bland cytology in myxoid matrix
containing lymphocytes and extravasated red blood cells.
Mitotic figures present, but not abnormal.

18. Nodular fasciitis
• Characteristically, the lesion
is several centimeters in
greatest dimension and
nodular with poorly defined
margins.
• Histologically, it is richly
cellular and consists of
plump, randomly arranged,
immature-appearing
fibroblasts in an abundant
myxoid stroma .
• The cells vary in size and
shape (spindle to stellate)
and have conspicuous
nucleoli and numerous
mitoses.

19. TUMORS OF FIBROUS TISSUE
FIBROMATOSES
Definition: Is a fibroblastic proliferation with
aggressive local growth and infiltrative margins.
recur after surgical excision and do not metastasize.
Two major groups:
 Superficial fibromatoses, include palmar fibromatosis
(Dupuytren’s contracture) and penile fibromatosis
(Peyronie’s disease), occur in superficial fascia and are
benign, have abundant collagen and result in
deforming contractures in palms or soles.
 Deep fibromatoses, called desmoid tumors, arise in
the abdomen, muscle of the trunk and extremities,
they recur and show local aggressive growth.

21. TUMORS OF FIBROUS TISSUE
FIBROMATOSES cont.
MORPHOLOGY
Gross: either well-defined nodules, infiltrative
masses
without margins.
Microscopically: composed of proliferating
Fibroblasts have uniform appearance.
Superficial
fibromatoses, contain abundant collagen.

22. TUMORS OF FIBROUS TISSUE
FIBROSARCOMAS
Fibrosarcomas are malignant neoplasms
composed of malignant fibroblasts.
Age: adults
Site: deep tissue of the thigh, knee and trunk.
They grow slowly many years before diagnosis.

24. TUMORS OF FIBROUS TISSUE
FIBROSARCOMAS
MORPHOLOGY
Gross: solitary lesions either infiltrative or
fairly circumscribed.
Histologically: interlacing fascicles of
fibroblasts, arrayed in a herringbone
pattern. Nuclear atypia and mitotic activity
present.
Prognosis: recur locally after excision and
may metastasize by blood to the lungs.

25. Fibrosarcoma

27. Lecture 10

28. TUMORS OF SMOOTH MUSCLE
Leiomyomas are benign smooth muscle tumors,
are common, well-circumscribed neoplasms.
Site: uterus, anywhere in the body.
Leiomyosarcomas are malignant smooth muscle
tumors.
Site:most often in uterus and gastrointestinal
tracts, or any area of the body.
Most arise de novo, than in a preexisting
leiomyoma.

29. Uterine Leiomyoma
• Characteristic whorled like

32. Leiomyoma:
Section of tumour shows:
A well demarcated tumour mass in the muscle coat
of uterus without a definite capsule.
Tumour consists of interlacing bundles of smooth
muscle and fibrous tissue.
The muscle cells are spindle shaped with
elongated nuclei and eosinophilic cytoplasm.

33. TUMORS OF SMOOTH MUSCLE
LEIOMYOSARCOMA
Morphology:
Have infiltrative growth, greater cellularity
and pleomorphism, greater mitotic activity
(mitotic activity used to differentiate benign
SMC tumor from malignant).

34. Cut surface of this leiomyosarcoma showing ill
defined pale and soft large fleshy mass with
hemorrhage and necrosis.

36. TUMORS OF SKELETAL MUSCLE
Rhabdomyoma
Is a benign skeletal muscle tumor.
Is an uncommon tumor.
The cardiac rhabdomyoma associated with
tuberous sclerosis.

37. TUMOR OF SKELETAL MUSCLE
RHABDOMYOSARCOMA
Rhabdomyosarcoma is a malignant aggressive
skeletal muscle tumor.
Age: infancy, childhood, and adolescence
The most common soft tissue sarcoma in
pediatric age.

38. TUMORS OF SKELETAL MUSCLE
MORPHOLOGY
Gross: is variable.
Tumor (sarcoma botryoides) arising near the
mucosal surfaces of the lower genitourinary tract
and in the head and neck.
Are soft, gelatinous, grape-like masses, other
variant may present as poorly defined mass or as
infiltrating mass.

39. TUMORS OF SKELETAL MUSCLE
Microscpically:
*Embryonal variants and sarcoma botryoides,
are composed of malignant small round cells
and eosinophilic large cells with evidence of
myoblastic differentiation.
They are subclassified into the embryonal,
alveolar, and pleomorphic variants.

40. TUMORS OF SKELETAL MUSCLE
Diagnosis:
Depend of the demonstration of skeletal
muscle differentiation, by the electron
microscope (sarcomeres),
or immunocytochemical (desmin).
DDX:
to be distinguished from other small round
cell tumors of childhood.

41. SKELETAL MUSCLE
• RHABDOMYOMA
• RHABDOMYOSARCOMA

42. Rhabdomyosarcoma

43. SYNOVIAL SARCOMA
Accounts for 10% of all soft tissue sarcomas.
Synovial sarcoma does not arise from
synovial cells,
rather, it arises form mesenchymal cells
about joint cavities or away from the joint
especially around the knee and thigh

44. SYNOVIAL SARCOMA
MORPHOLOGY
Gross: can be small, circumscribed lesions or
infiltrative sarcomatous masses.
Histologically: biphasic pattern, epithelial
component forming glands, mixed with spindle
cells similar to fibroblast..
Less frequent monophasic, either composed of
epithelial elements that resemble a carcinoma
or,
of spindle cells sarcoma.

47. Assessment
–Which of the following statements is TRUE
for Liposarcoma?
• A. Usually show benign behavior
• B. The most common site is subcutaneous
tissue
• C. Histologically shows mature fat cells
arranged in lobules.
• D. Grossly, shows invasive growth with
hemorrhage and necrosis.

48. Assessment
–The most common soft tissue sarcoma of
infancy and childhood is:
• A. Rhabdomyosarcoma
• B. Liposarcoma
• C. Myositis ossificans
• D. Malignant fibrous histiocytoma