A detailed brief overview of Lipoma!!

·        It is a benign neoplasm arising from yellow fat.

·        Often it can be hyperplasia or a combination of neoplasm and hyperplasia.

·        A lipoma is composed of mature adipocytes and uniform nuclei that are identical to those in normal adult fat.

·        The fat in lipoma is considered unavailable for general metabolism.

  What is the Etiopathogenesis of Lipoma?

Ø  It is the most common benign tumor (Karyotype 12q change). Prevalence is 2.1 per 100 people.

Ø  It is called a universal tumor (ubiquitous tumor) as it can occur anywhere in the body except the brain.

Ø  It can be localized ( encapsulated-with yellowish-orange color) or diffuse( nonencapsulated-difficult to remove surgically; recurrence is high after incomplete removal).

Ø   

Lipoma can be superficial or deep

1.     Superficial lipomas- more common; in the subcutaneous plane. it is common in the back, neck, proximal extremities, and abdomen. It is commonly less than 5 cm but can attain a large size. There is no gender predisposition.

2.     Deep lipomas are commonly intramuscular, but often both intra and intermuscular; They are common in the lower limb, trunk, shoulder, and upper limb. They are more common in men.

Lipoma can be single or multiple:

       I.            Single lipoma is common. It is usually superficial in the subcutaneous plane but can be deep also.

    II.            Multiple lipomas are common in males. common in the back shoulder and upper arm; can be symmetrical. It can be associated with many syndromes like Multiple Endocrine Neoplasia(MEN), Cowden's, Frohlich, Proteus, bannayan-Zonana syndromes.

 III.            Multiple lipomatosis represents a diffuse overgrowth of mature adipose tissue. involves subcutaneous and muscular planes extensively; common in shoulder and pelvic girdles. It is common in the younger age groups. 30% of them are familial.

What is Dercum’s disease?

Adipose Dolorosa (Dercum's disease) is a multiple lipomatosis mainly seen in females(30:1)(female to male ratio).

There is tender fat deposition, especially in trunk and girdles.

 It is common in epileptic and psychiatric patients.

What is Hibernoma?

Benign tumor arising from brown fat is called Hibernoma(reddish-brown) which has got serpentine vascular elements.

What is Fibro-lipoma?

Lipoma with fibrous component is called fibro-lipoma (most frequent non-lipomatous component of lipomas fibrous tissue).

Fibrolipoma is nonseptal.

What is Naevolipoma?

Lipoma with telangiectasis is called as naevolipoma.

What is Angiolipoma?

Neurolipoma(with nerve tissue is painful), angiolipoma(with vascular element), myolipoma, chondroid lipoma, spindle cell lipoma, pleomorphic lipoma-are different types depending on the type of non-adipose component associated.

What is lipoblastoma?

Lipoblastoma is a benign tumor of immature fat occurring in infant boys in the subcutaneous tissue of extremity.

o   Benign lipomatous lesions may occur focally in a joint or tendon sheath or with diffuse villonodular proliferation in the synovium-Lipoma arborescent. Synovectomy may be needed in this patient.

o   Malignant transformation of lipoma is non-existent. Liposarcoma does not arise from mature fat cells but from primitive mesenchymal cells.

Clinical features:

v Localized swelling, which is lobular)surface, non-tender.

v Often fluctuant like feel but actually not (because fat in body temperature remains in semiliquid condition). It is usually non-transilluminant.

v Mobile with edges slipping between the palpating fingers(slip fingers)

v Skin is free

v Lipomas may be pedunculated at times.

v It is rare in children.

v Pain in lipoma may be due to neural elements or compression to nerves or adjacent structures. Angiolipomas being vascular is commonly tender.

v Trunk is the most common site; nape of neck and limbs are next common.

v Clinically lipoma can be single, multiple or diffuse.

A diagnostic criterion used by some clinicians for superficial lipomas is the hardening of the swelling after application of ice.

Differential diagnosis:

ü  Neurofibroma: it moves horizontally but not longitudinally along the line of nerve.

ü  Cystic swellings: dermoid, sebaceous cysts

ü  Liposarcomas: large lipomas should be differentiated from liposarcomas.

ü  Other soft tissue tumors.

Investigations:

o   USG or CT or MRI imaging in deep or large or intracavitary lipomas.

o   FNAC or incision biopsy

Complications:

§  Myxomatous changes

§  Saponification

§  Calcification

§  Submucosal lipoma -intussusception and so intestinal obstruction.

Treatment:

Ø  Excision

Ø  Small lipoma is excised under local anesthesia and larger ones under general anesthesia.

Ø  Recurrence is 11%