Lipomatosis

Definition

• Diffuse or regional overgrowth of fat

Diagnostic Criteria

• Diffuse or regional overgrowth of mature fat
  • May be difficult to distinguish from multiple discrete lipomas
  • May infiltrate adjacent skeletal muscle
• Diffuse lipomatosis
  • Diffuse overgrowth of mature fat
  • Usually involves a large region of an extremity or trunk
  • Age usually under 2 years
  • Involves muscle and subcutaneous tissue
    • Does not involve nerves
  • Recurs frequently
• Encephalocraniocutaneous lipomatosis
  • Haberland syndrome
  • Lipomatous hamartomas of the head and face
    • Usually unilateral
  • Congenital
  • Cranial asymmetry and mental retardation
• Fibrolipomatous hamartoma of nerve / neural fibrolipoma / lipomatosis of nerve
  • Mature adipose tissue with a fibrous component
    • Epineural and perineural fibrosis
    • Metaplastic bone has been reported
  • Surrounds and infiltrates a segment of a major nerve
    • Most often involves median nerve
  • May have associated bone overgrowth causing macrodactyly
    • Usually under age 30
    • Usually causes neural signs and symptoms
    • Benign but may require excision or release of compression
• Lumbosacral lipoma / lipomatosis
  • Diffuse increase in mature fat over lumbosacral spine
  • Spina bifida or laminar defect always present
    • Meningocele or myelocele may be present
  • Usually in infants and children
  • May have associated skin tags, hemangioma or hair overgrowth
• Pelvic lipomatosis
  • Perivesical and perirectal overgrowth
    • Rarely involves retroperitoneum and mesentery
    • Frequent cystitis glandularis
      • May develop adenocarcinoma
  • Usually in black males
  • Age 9-80
• Symmetrical lipomatosis
  • Madelung or Launois-Bensaude syndrome
  • Usually neck, shoulders, upper arms
  • Described as pseudoathletic or horse collar
  • Frequently associated with diabetes and alcohol abuse
  • More common in men of Mediterranean origin

Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342

Original posting : July 29, 2007

Supplemental studies

Immunohistology

• S100 stains mature fat but is seldom of diagnostic use

Differential Diagnosis

	Distribution	Age	Associations
Encephalocranial Lipomatosis	Head and face	Congenital	Cranial asymmetry, mental retardation
Diffuse Lipomatosis	Regional	Infant
Fibrolipomatous Hamartoma of Nerve	Segment of major nerve	Usually <30	Macrodactyly
Lumbosacral Lipomatosis	Lumbosacral	Infant	Spina bifida
Pelvic Lipomatosis	Perivesicular or perirectal	9-80	Cystitis glandularis
Symmetrical Lipomatosis	Neck and shoulders	Adult	Alcohol, diabetes

Fibrolipomatous Hamartoma of Nerve	Lipofibromatosis
Fat with fibrous component	Fat with cellular fibroblastic septa
Centered on and surrounds a major nerve	Soft tissue mass, may surround nerve focally
Frequently associated with macrodactyly	Not associated with macrodactyly

Clinical

• May cause problems due to local overgrowth
  • May obstruct adjacent structures such as trachea, GI or genitourinary tract
• Many have associated abnormalities

Lists

Lipogenic tumors

• Angiomyolipoma
• Hemosiderotic Fibrohistiocytic Lipomatous Lesion
• Hibernoma
• Lipofibromatosis
• Lipoma
• Lipomatosis
• Lipoblastoma / lipoblastomatosis
• Pleomorphic lipoma
• Spindle cell lipoma
• Atypical lipomatous tumor
• Liposarcoma
  • Dedifferentiated
  • Myxoid
  • Pleomorphic
  • Unclassified

Bibliography

• Kempson RL, Fletcher CDM, Evans HL, Henrickson MR, Sibley RS. Tumors of the Soft Tissues, Atlas of Tumor Pathology, AFIP Third Series, Fascicle 30, 2001
• Fletcher CDM, Unni KK, Mertens F. Pathology and Genetics of Tumours of Soft Tissue and Bone, World Health Organization Classification of Tumours 2002
• Weiss SW, Goldblum JR. Enzinger and Weiss's Soft Tissue Tumors, 4th edition, 2001
• Campen RB, Sang CN, Duncan LM. Case records of the Massachusetts General Hospital. Case 25-2006. A 41-year-old woman with painful subcutaneous nodules. N Engl J Med. 2006 Aug 17;355(7):714-22.
• Nixon HH, Scobie WG. Congenital lipomatosis: a report of four cases. J Pediatr Surg. 1971 Dec;6(6):742-5.
• Tong RS, Larner T, Finlay M, Agarwal D, Costello AJ. Pelvic lipomatosis associated with proliferative cystitis occurring in two brothers. Urology. 2002 Apr;59(4):602.
• Hirose A, Okada Y, Morita E, Tanaka Y. Benign symmetric lipomatosis associated with alcoholism. Intern Med. 2006;45(17):1001-5.
• Fernandez-Vozmediano J, Armario-Hita J. Benign symmetric lipomatosis (Launois-Bensaude syndrome). Int J Dermatol. 2005 Mar;44(3):236-7.
• Lassman LP, James CC. Lumbosacral lipomas: critical survey of 26 cases submitted to laminectomy. J Neurol Neurosurg Psychiatry. 1967 Apr;30(2):174-81.
• Rubegni P, Risulo M, Sbano P, Buonocore G, Perrone S, Fimiani M. Encephalocraniocutaneous lipomatosis (Haberland syndrome) with bilateral cutaneous and visceral involvement. Clin Exp Dermatol. 2003 Jul;28(4):387-90.
• Silverman TA, Enzinger FM. Fibrolipomatous hamartoma of nerve. A clinicopathologic analysis of 26 cases. Am J Surg Pathol. 1985 Jan;9(1):7-14.
• Bisceglia M, Vigilante E, Ben-Dor D. Neural lipofibromatous hamartoma: a report of two cases and review of the literature. Adv Anat Pathol. 2007 Jan;14(1):46-52.