Lipomatosis is believed to be an autosomal dominant condition in which multiple lipomas are present on the body. Many discrete, encapsulated lipomas form on the trunk and extremities, with relatively few on the head and shoulders. In 1993, a genetic polymorphism within lipomas was localized to chromosome 12q15, where the HMGIC gene encodes the high-mobility-group protein isoform I-C. This is one of the most commonly found mutations in solitary lipomatous tumors but lipomas often have multiple mutations. Reciprocal translocations involving chromosomes 12q13 and 12q14 have also been observed within.
Although this condition is benign, it can sometimes be very painful depending on location of the lipomas. Some patients who are concerned with cosmetics seek removal of individual lipomas. Removal can include simple excision, endoscopic removal, or liposuction.
Other entities which are accompanied by multiple lipomas include Proteus syndrome, Cowden syndrome and related disorders due to PTEN gene mutations, benign symmetric lipomatosis (Madelung disease), Dercum's Disease, familial lipodystrophy, hibernomas, epidural steroid injections with epidural lipomatosis, and familial angiolipomatosis.
- Pelvic lipomatosis — A rare disease most often seen in older obese black men with hypertension.
- Virchow's metamorphosis — lipomatosis in the heart and salivary glands.
- Dercums — A rare condition characterized by generalized obesity and painful fatty tumors in the adipose tissue.