Dermatologic Manifestations of Localized Lipodystrophy Workup

Updated: May 22, 2020
  • Author: Robert A Schwartz, MD, MPH; Chief Editor: Dirk M Elston, MD  more...
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Workup

Laboratory Studies

No associated laboratory abnormalities are present in most cases of localized lipodystrophy.

Complete blood counts, chemistry, erythrocyte sedimentation rate, renal function tests, and serum antibody tests should be performed in search of an underlying autoimmune condition in cases associated with panniculitis.

A transient microcytic anemia, thrombocytosis, and elevated erythrocyte sedimentation rate have been reported in cases of lipophagic panniculitis.

Serum antinuclear antibodies may be positive in cases associated with an autoimmune disorder.

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Procedures

A skin biopsy of an affected area deep enough to include the subcutaneous tissue should be performed to confirm the diagnosis and to exclude underlying conditions. Direct immunofluorescence testing should be requested.

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Histologic Findings

Centrifugal lipodystrophy is characterized by a loss of fat in the depressed area and evidence of panniculitis in the surrounding inflammatory area.

A pattern of involutional lipoatrophy is the common finding in the second subgroup, whether idiopathic or associated with a history of trauma, pressure, or local injections. Individual adipocytes and fat lobules are smaller and fewer, separated by hyaline material, with prominent and numerous capillaries, and minimal or no inflammation is present. No foreign body giant cell or lipophage is present.

Histologic evidence of panniculitis is usually present if a biopsy is performed on lesions early enough in the third subgroup. A combination of lipoatrophy and a predominantly lymphocytic or histiocytic infiltrate made of lipophages is most commonly found. Other features may vary with the underlying cause of panniculitis.

Lipophagic panniculitis is characterized by a panlobular panniculitis with a predominantly histiocytic infiltrate made of foamy and Toutonlike lipophages in the subcutaneous and periappendageal fat, giving it a granulomatous appearance. Immunofluorescence study findings are negative.

In cases of panniculitis associated with connective-tissue disorders, histopathologic findings may be diagnostic of lupus, scleroderma, dermatomyositis, or overlap disease, but they are not always specific. Lupus panniculitis is best defined as a mostly lobular panniculitis with a predominantly lymphocytic infiltrate. Lymphoid follicles with germinal centers around the septa and hyaline fat necrosis, when present, are characteristic. Changes may be confined to the subcutaneous tissue in about one half of cases, or the overlying epidermis and dermis may show evidence of discoid lupus erythematosus, such as epidermal atrophy, hyperkeratosis, hydropic degeneration of the dermoepidermal junction, and perivascular and appendageal lymphocytic infiltration of the overlying skin. Direct immunofluorescence findings are positive in most patients, with linear deposits of immunoglobulin M and C3 along the dermoepidermal junction.

Morphea profunda shows thickening and hyalinization of the septal panniculus and fascia. Small aggregates of lymphocytes and plasma cells as well as eosinophils may be observed and help in differentiating it from lupus.

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