Benign lesion (Nevi, pilomatrixoma, lipoma, dermoid, epidermoid cyst)

Question 1

Classification of soft tissue lesions?

Answer 1

Cystic vs Solid followed by tissue origin:

Solid:

• Epidermal/Adnexal
• peripheral nerve
• Fibrous tissue (fibroblastic, myofibroblastic, fibrohystiocytic)
• Smooth muscle
• Skeletal muscle
• Pericytic
• condro-osseous
• adipose

Question 2

Common cystic soft tissue lesions?

Answer 2

Dermoid, epidermal, trichilemmal, synovial, ganglion.

Question 3

Epidermal/Soft tissue solid lesions?

Answer 3

1) pyogenic granuloma
2) pilomatrixoma
3) verruca vulgaris

Question 4

Peripheral nerve masses?

Answer 4

1) Fibrolipomatous hamartoma of nerve
2) Schwannoma
3) neurofibromas
4) neurothecoma
5) granular cell tumor

Question 5

Fibrous tissue masses?

Answer 5

1) Nodularfasciitis
2) Fibrous hamartoma of infancy
3) Myofibroma
4) benign fibrous histiocytoma
5) Juvenile xanthogranuloma

Many others…

Question 6

Smooth muscle masses?

Answer 6

1) Leiomyoma

2) angioleiomyoma

Question 7

Skeletal muscle masses?

Answer 7

Rhabdomyoma

Question 8

Pericytic (perivascular) masses?

Answer 8

Glomus tumor

Question 9

Chondro-osseous masses?

Answer 9

Chondromas

Question 10

Adipose tissue masses?

Answer 10

Lipoma

Lipoblastoma

Question 11

General imaging of soft tissue masses?

Answer 11

Plain X-ray: for diagnosis of calcifying lesions or chondro-osseous lesions. Gives information on bony erosion/invasion.

U/S: Good for superficial lesions to differentiate solid vs cystic. Also good for vascular lesions with Doppler.

MRI: Gold standard for most soft tissue lesions. Gives best information on surrounding structures when planning resection.

CT: Rarely indicated.

Question 12

Epidermal cysts management?

Answer 12

Respect due to risk of infection, contain ectodermal elements only.

Question 13

Dermoid cysts management?

Answer 13

Contain dermal and ectodermal elements.

Should be removed as they will continue to increase in size. Angular Dermoids can be disfiguring if left.

Question 14

Pilomatrixoma management?

Answer 14

Found in the head & neck, and upper extremity.
Case reports of malignancy
Resect electively

Question 15

Nodular Fasciitis management?

Answer 15

Proliferation of fibroblasts/myofibroblasts- usually superficial but may occur in muscles.
Grow rapidly in the H&N, trunk, arms.

Excise electively- rarely recur

Question 16

Fibrous hamartoma of infancy management?

Answer 16

Benign tumor occurs in the first 2 years of life, 1/4 congenital.
Occurs in shoulder, axilla, and upper arm.

Excise completely or risk local recurrence.

Question 17

Myofibroma management?

Answer 17

Multi centric or generalized lesions present at birth- may affect organs but most commonly affect skin, bone. Generalized in often fatal.

Solitary - occurs later in childhood.

Multi centric and solitary grow through the first year and then regress.

Excision for form/function.

Question 18

Lipoblastoma management?

Answer 18

Occurs as encapsulated lipoblastoma or lipoblastomatosis.

PLAG1 gene hybrid molecular testing for diagnosis.

Treat with excision. 1/5 reoccur due to incomplete excision - especially lipoblastomatosis which can grow between muscular planes.

Question 19

Neurofibroma management?

Answer 19

Occurs as sporadic solitary lesions or multiple in NF-1
They are peripheral nerve sheath tumours.

Remove if symptomatic

Question 20

Ganglion/synovial cysts?

Answer 20

Occurs near joint spaces

Ganglion most common in wrists - generally observe due to high recurrence

Synovial most common near knee