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Flashcards in Miller-Soft tissue tumors Deck (26)
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1

Soft tissue tumor introduction

Soft tissue tumors are common. They may appear as painless small lumps or large masses.

Soft tissue tumors can be broadly classified as benign or malignant (sarcoma) or characterized by reactive tumorlike conditions.

Lesions are further classified according to composition; for example, whether they tend to produce collagen (fibrous lesion), fat, or vascular tissue.

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What are the soft tissue tumors with lymph node metastasis?

ESARC

3

Review malignant soft tissue tumors

Presentation

Masses are deceptively painless and commonly are inappropriately assumed to be lipomas.

A mass that is more than 5 cm, growing, and deep to the superficial fascia should be presumed to be a soft tissue sarcoma (STS) until proven otherwise, and it should be assessed with three-dimensional imaging first (ideally MRI).

Patients often experience enlarging painless or painful soft tissue masses.

In some instances, the masses are small and may be present for a long time before they are recognized as tumors

Imaging

MRI is the best imaging modality for defining the anatomy of and helping characterize the lesion.

MRI provides information on tumor size, grade, depth, and anatomic location and aids in surgical planning.

On T1-weighted images, STSs have a high signal intensity (isointense with muscle), and on T2-weighted images, they have a low signal intensity.

With the administration of intravenous gadolinium contrast agent, an STS typically demonstrates a peripheral enhancing zone and a nonenhancing, necrotic center.

CT of the chest is performed to evaluate for metastasis.

Treatment

Radiation therapy is an important adjunct to surgery in the treatment of soft tissue sarcomas.

External beam irradiation can be delivered preoperatively or postoperatively with the same oncologic outcome.

Intensity-modulated radiation therapy (IMRT) is a common type of external beam radiation therapy used for soft tissue sarcomas.

Other features

In the United States, approximately 12,000 new cases of soft tissue sarcoma are diagnosed each year.

Poor prognostic factors include the presence of metastases, high histologic grade, and size greater than 5 cm. Unplanned removal of a soft tissue sarcoma is the most common error in treatment of STSs.

Residual tumor may exist at the site of the operative wound, and in all patients with an unplanned removal, repeat excision should be performed.

Delay in diagnosis may also occur if the clinician does not recognize that the lesion is malignant.

Metastasis: Most soft tissue sarcomas metastasize to the lung.

Lymph node metastasis occurs with 5% of soft tissue sarcomas.

Epithelioid sarcoma, synovial sarcoma, angiosarcoma, rhabdomyosarcoma, and clear cell sarcoma (mnemonic: ESARC) are the tumors that most commonly metastasize to the lymph nodes (Table 9.17

4

Review MFH or 

UPS

Undifferentiated pleomorphic sarcoma (UPS; previously malignant fibrous histiocytoma).

Histology: The spindle and histiocytic cells are arranged in a storiform (cartwheel) pattern. Short fascicles of cells and fibrous tissue appear to radiate about a common center around slitlike vessels. Chronic inflammatory cells may also be present.

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Review Fibrosarcoma

Fibrosarcoma

Histology: There is a fasciculated growth pattern, with fusiform or spindle-shaped cells, scanty cytoplasm, and indistinct borders, and the cells are separated by interwoven collagen fibers. There is a herringbone pattern, which consists of intersecting fascicles in which the nuclei in one fascicle are aligned transversely but in an adjacent fascicle are aligned longitudinally.

6

Review Malignant Peripheral Nerve Sheet tumor

MPNST

Histology: Spindle cells arranged in sweeping fascicles, with areas of nodular and whorled appearance. Immunohistochemistry shows S-100 positivity.

Other features: Tumor may arise de novo or in the setting of neurofibromatosis.

7

Review Leiomyosarcoma

Leiomyosarcoma

Histology: Fascicular growth pattern with spindle cells that intersect at right angles; IHC: positivity for SMA and desmin.

8

Review Angiosarcoma

Angiosarcoma

Histology: Cells resemble endothelium of blood vessels.

Other features

Highly malignant

Lymph node and cutaneous metastases are common (ESARC).

Infiltrative with poor margins; amputation may be necessary to achieve local control.

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Review Liposarcoma

Liposarcoma

Presentation: Liposarcomas rarely occur in the subcutaneous tissues.

Histology: Heterogeneous group of tumors, having in common the presence of lipoblasts (signet ring–shaped cells)

Other features

They are classified into the following types:

Well-differentiated liposarcoma (low grade) (Fig. 9.6 in Table 9.18)




 

 


 

Lipomalike

Sclerosing

Inflammatory

Myxoid liposarcoma (intermediate grade)

Dedifferentiated (high grade) (Fig. 9.7 in Table 9.18)

Round cell liposarcoma (high grade)

Pleomorphic liposarcoma (high grade)

Liposarcomas metastasize according to the grade of the lesion.

Well-differentiated liposarcomas have a very low rate of metastasis (<10%).

The metastasis rate of intermediate-grade liposarcomas is 10%–30%.

The metastasis rate of high-grade liposarcomas is more than 50%

10

Review Rhabdomyosarcoma

Rhabdomyosarcoma

Presentation

Rapidly growing soft tissue mass in a patient less than 30 years old

The most common sarcoma in young patients

Histology

Racquet-shaped cells and cross-striations within the tumor cells (rhabdomyoblasts); IHC: positivity for myogenin and MyoD1

Treatment: Rhabdomyosarcomas are sensitive to multiagent chemotherapy and wide-margin surgical resection after chemotherapy. External beam irradiation may also also used.

11

Review Synovial Sarcoma

Synovial sarcoma

Presentation

May be present for years or may manifest as a rapidly enlarging mass in patients less than 30 years of age

Synovial sarcoma is the most common sarcoma in the foot.

Imaging

Radiographs or CT may show mineralization within the lesion in up to 25% of cases (spotty mineralization may even resemble the peripheral mineralization seen in heterotopic ossification).

Histology

The tumor is often biphasic, with both epithelial and spindle cell components. It may be monophasic with spindle cells only.

The epithelial component may show epithelial cells that form glands or nests, or they may line cystlike spaces.

IHC: Positivity for keratin and epithelial membrane antigen (EMA)

Genetics

Translocation between chromosome 18 and the X chromosome—t(X;18)—is always present in tumor cells, and staining of the tumor cells yields positive results for keratin and EMA.

The balanced translocation results in gene fusion products. The two most common are SYT-SSX1 and SYT-SSX2.

Treatment

Wide surgical resection with adjuvant radiotherapy (XRT) is the most common method of treatment.

Synovial sarcoma is an unusual soft tissue sarcoma in which chemotherapy has shown a clinical benefit.

Other features

Lymph nodes may be involved (ESARC).

The name is derived from the histologic appearance, not from origination from the synovium. This is not an intraarticular tumor

12

Review Epitheliod Sarcoma

Epithelioid sarcoma

Presentation

Rare nodular tumor that commonly occurs in the upper extremities of young adults

The most common sarcoma of the hand

Histology: Cells range in shape from ovoid to polygonal, with deeply eosinophilic cytoplasm (cellular pleomorphism is minimal).

Treatment: Wide-margin surgical resection

Differential diagnosis: Granuloma, rheumatoid nodule, or inclusion cyst. Often misdiagnosed as benign process.

13

Review Clear Cell Sarcoma

Clear cell sarcoma

Presentation

Slow-growing mass in association with tendons or aponeuroses

Usually occurs about the foot and ankle but may also involve the knee, thigh, or hand

Histology: Characterized by compact nests or fascicles of rounded or fusiform cells with clear cytoplasm; multinucleated giant cells are common.

Treatment: Wide-margin surgical resection with adjuvant radiation

Other features: Metastases to lymph nodes (ESARC)

14

Review Dermatofibrosis Protuberans

Dermatofibrosarcoma protuberans

Presentation

Rare, nodular, cutaneous tumor that occurs in early to middle adulthood

A low-grade tumor with a tendency to recur locally that rarely metastasizes

Histology: The central portion of the nodules shows uniform fibroblasts arranged in a storiform pattern around an inconspicuous vasculature.

Treatment: Wide-margin surgical resection, which may require skin grafting

15

Review Fibromatosis

Fibromatosis

Palmar (Dupuytren) and plantar (Ledderhose) fibromatoses: These disorders consist of firm nodules of fibroblasts and collagen that develop in the palmar and plantar fascia. The nodules and fascia become hypertrophic, producing contractures.

Extraabdominal desmoid tumor; most locally invasive of all benign soft tissue tumors.

Presentation

Commonly occurs in adolescents and young adults

Patients with Gardner syndrome (familial adenomatous polyposis) have colonic polyps and a 10,000-fold increased risk for development of desmoid tumors.

On palpation, the tumor has a distinctive “rock-hard” character.

Multiple lesions may be present in the same extremity (10%–25%).

Histology:

Well-differentiated fibroblasts and abundant collagen. The lesion infiltrates adjacent tissues.

IHC: Positivity for estrogen receptor β and β-catenin

Treatment

Medical management including NSAIDS, tamoxifen, and cytotoxic chemotherapy

Behavior of the tumor is unpredictable: Recurrent nodules may remain dormant for years or may grow rapidly for some time and then stop growing, especially in pregnancy because of the high level of circulating estrogen.

Nodular fasciitis

Presentation: A common reactive lesion that manifests as a painful, rapidly enlarging mass in the upper extremity of a young person less than 30 years old

Histology: Short, irregular bundles and fascicles; a dense reticulum network; and only small amounts of mature collagen characterize the lesion histologically. Mitotic figures are common, but atypical mitoses are not a feature.

Treatment: Wide marginal excision

16

Review Lipoma

Lipomas: Common benign tumors of mature fat

Presentation

Painless lesion that occurs in a subcutaneous, intramuscular, or intermuscular location

History of a mass is long, but sometimes the mass is only recently discovered.

Imaging

Radiographs may show a radiolucent lesion in the soft tissues if the lipoma is deep within the muscle or between the muscle and bone.

CT or MRI shows a well-demarcated lesion with the same signal characteristics as those of mature fat on all sequences. On fat suppression sequences, the lipoma has a uniformly low signal (see Fig. 9.5).

Treatment: If the mass is growing or causing symptoms, excision with a marginal resection is performed.

Differential diagnosis: Liposarcoma

17

Review tumors of neural tissue

Schwannoma (a.k.a. neurilemoma): Benign nerve sheath tumor

Presentation: Mass that may be painful and associated with the presence of Tinel sign.

Imaging: MRI may demonstrate an eccentric mass arising from a peripheral nerve or may show only an indeterminate soft tissue mass (low signal on T1-weighted images and high signal on T2-weighted images).

Histology

The lesion is composed of Antoni A and B areas.

Antoni A area

Compact spindle cells usually having twisted nuclei, indistinct cytoplasm, and, occasionally, clear intranuclear vacuoles

There may be nuclear palisading, whorling of cells, and Verocay bodies.

Antoni B area

Less orderly and cellular

Arranged haphazardly in the loosely textured matrix (with microcystic changes, inflammatory cells, and delicate collagen fibers)

Treatment: Intraneural excision for painful or symptomatic masses

Neurofibroma: Solitary or multiple (neurofibromatosis)

Presentation: Superficial/skin lesions, slow-growing and painless

Histology: Interlacing spindle cells with wavy, dark-staining nuclei with no pleomorphism

Treatment: Excision with a marginal margin

Neurofibromatosis (von Recklinghausen disease)

Autosomal dominant trait (both peripheral and central forms)

Café au lait spots (smooth) and Lisch nodules (melanocytic hamartomas in the iris)

Variable skeletal abnormalities (metaphyseal fibrous defect [nonossifying fibroma], scoliosis, and bowing of long bones)

Pain and an enlarging soft tissue mass may herald conversion to a sarcoma (5%–30% of affected patients).

18

Review PVNS

Pigmented villonodular synovitis (PVNS)

Reactive condition (not a true neoplasm) characterized by an exuberant proliferation of synovial villi and nodules

May occur locally (within a joint) or diffusely

Presentation

The knee is affected most often, followed in frequency by the hip and shoulder.

Manifests as pain and swelling in the affected joint

Recurrent, atraumatic hemarthrosis is the hallmark (arthrocentesis demonstrates a bloody effusion).

Imaging: Cystic erosions may occur on both sides of the joint.

Histology: Highly vascular villi are lined with plump, hyperplastic synovial cells; hemosiderin-stained, multinucleated giant cells; and chronic inflammatory cells.

Treatment

Aimed at complete synovectomy by arthroscopy for resection of all the intraarticular disease, followed by open posterior synovectomy to remove the posterior extraarticular extension

The local form of PVNS may be treated with partial synovectomy.

19

Review AVMS

Vascular malformation, also known as hemangioma or arteriovenous malformation (AVM)

Presentation

Cutaneous, subcutaneous, or intramuscular lesion

Large tumors have signs of vascular engorgement (aching, heaviness, swelling).

It is helpful to examine the patient in both the supine and standing positions (the lesion often fills with blood after several minutes of gravity dependence).

Imaging

Radiographs may reveal small phleboliths.

MRI demonstrates a heterogeneous lesion with numerous small blood vessels and fatty infiltration.

Treatment

NSAIDs, vascular compression stockings, and activity modification if local measures adequately control discomfort

Sclerotherapy using an intralesional sclerosing agent such as alcohol

Surgical resection may be performed for lesions refractory to other therapy; local recurrence rate is high.

20

Review Synovial chondromatosis

Synovial chondromatosis

Synovial proliferative disorder that occurs within joints or bursae, ranging in appearance from metaplasia of the synovial tissue to firm nodules of cartilage

Presentation

Patients less than 30 years old present with pain, stiffness, and swelling.

The knee is the most common location.

Imaging: Demonstrates intraarticular fine, stippled calcification known as rice bodies

Treatment: Arthroscopic resection of the rice bodies and synovectomy

21

Review clinical pearls for soft tissue sarcomas

Synovial chondromatosis

Synovial proliferative disorder that occurs within joints or bursae, ranging in appearance from metaplasia of the synovial tissue to firm nodules of cartilage

Presentation

Patients less than 30 years old present with pain, stiffness, and swelling.

The knee is the most common location.

Imaging: Demonstrates intraarticular fine, stippled calcification known as rice bodies

Treatment: Arthroscopic resection of the rice bodies and synovectomy

22

Immunohistochemistry for synovial:

IHC: Positivity for keratin and epithelial membrane antigen (EMA)

23

Immunohistochemistry for nerve sheeth tumors

S-100

24

Review immunohistochemistry for Rhabdo

Racquet-shaped cells and cross-striations within the tumor cells (rhabdomyoblasts); 

 

IHC: positivity for myogenin and MyoD1

25

what is the immunohistochemistry for Rhabdomyosarcoma?

 IHC: positivity for SMA and desmin

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