J AM ACAD DERMATOL

VOLUME 60, NUMBER 3

Letters 519

RESEARCH LETTER

Does segmental lipodystrophy representmosaicism of inherited lipodystrophy?

To the Editor: Lipodystrophy is a rare, heterogeneous

group of diseases characterized by the absence ofsubcutaneous fat over part of or the entire bodysurface.1 Lipodystrophy is classified into two maingroups, acquiredor inherited,which in turn comprisefour and three subgroups, respectively.1,2 Each typeof lipodystrophy has a unique clinical appearanceand underlying pathogenic mechanism (Table I).1,2

A 13-year-old female with a prominent loss ofsubcutaneous fat on the lateral side of her left lowerlimb presented to our dermatology clinic. The pa-tient’s mother noticed the presence of a small,depressed area at the gluteal muscle region of the

left lower limb since 6 months of age. As the patient

grew, a further gradual loss of subcutaneous fatcaused this depression to become more prominent

and extend downward. The patient had no mental orphysical developmental abnormalities or any re-

markable medical history, such as febrile disease orabnormal medical or drug medication. In addition,

there was no family history of lipodystrophy.Upon physical examination, the patient’s lipoat-

rophy extended from the gluteal fossa to the dorsalsurface of her left foot without any other involve-

ment. This skin distribution was segmental. The skinoverlying the areas of lipoatrophy was brown, thin,

smooth, and not sclerotic. Superficial veins andmuscularity were prominent because of the loss of

Table I. Classification of lipodystrophies

Type of lipodystrophy Mode of inheritance Gene involved Clinical features

AcquiredLipodystrophy in HIV-infected patients — — Loss of subcutaneous fat from the face,

arms, and legs, and excess fat in theneck and abdomen

Acquired partial lipodystrophy — — Loss of fat from the face, neck, arms, andtrunk, and sparing of legs

Acquired generalized lipodystrophy — — Generalized loss of fat associated withtender subcutaneous nodules,autoimmune or other diseases

Localized lipodystrophy — — Loss of subcutaneous fat from smallareas

InheritedCongenital generalized lipodystrophy

Type 1 Autosomal recessive AGPAT2 Extreme lack of adipose tissue since birthType 2 Autosomal recessive seipin Extreme lack of adipose tissue since

birth, mild mental retardation, andcardiomyopathy

Familial partial lipodystrophyDunnigan variety Autosomal dominant LMNA Loss of subcutaneous fat from the arms,

legs, and trunk (sparing the face andneck) at puberty

PPAR-g mutations Autosomal dominant PPAR- g Loss of subcutaneous fat from the arms,legs, and face

Mandibuloacral dysplasiaType A lipodystrophy Autosomal recessive LMNA Skeletal anomalies and loss of

subcutaneous fat from the arms, legs,and trunk

Type B lipodystrophy Autosomal recessive ZMPSTE24 Skeletal anomalies, generalized loss offat, premature renal failure, andprogeria-like features

AGPAT2, 1-acylglycerol-3-phosphate-o-acyltransferase 2; LMNA, lamin A/C; PPAR-g, peroxisome proliferator activated receptor-g; ZMPSTE24,

zinc metalloproteinase.

Adapted with permission from Garg.1

J AM ACAD DERMATOL

MARCH 2009

520 Letters

Fig 1. Linear patterned atrophic skin over the lateral aspect of the left leg with prominentsubcutaneous blood vessels and muscularity. The atrophic fat distribution shows a segmentalpresentation (gray dotted line).

subcutaneous tissue (Fig 1). To analyze metabolicabnormalities and autoimmune diseases, severallaboratory tests were conducted, including liverfunction, glucose tolerance, fasting glucose, choles-terol, triglyceride, complete blood component tests,complements C3 and C4, and antinuclear antibody.All laboratory tests were within normal limits.Histopathologic findings showed a marked decreaseand degeneration of subcutaneous fat cells (Fig 2).Additionally, although this segmental distributionresembled segmental morphea, the histologic find-ings showed a normal dermis without scleroticchange.

Inherited lipodystrophies are classified into sev-eral subtypes by mode of inheritance, involved gene,and clinical features, such as area of involvement andtime of onset (Table I).1,2 Although our case issporadic, with no family history, it belongs to theinherited category according to Garg’s classificationbecause the patient’s fat loss had progressed sincebirth. However, the patient’s clinical features do notcorrelate with Garg’s classification of inherited lipo-dystrophy. Our case appears as a skin disorder with

some patterned lesion distribution along the linesof Blaschko. The lines of Blaschko are known torepresent pathways of embryonic development.3,4

Therefore, mosaicism as a mechanism could beconsidered an explanation of the present case.Mosaicism can result from a postzygotic mutationoccurring in either the gonads (germline mosaicism)

Fig 2. Marked decrease and degeneration of subcutane-ous fat cells. (Hematoxylineeosin stain; original magnifi-cation: 3200).

J AM ACAD DERMATOL

VOLUME 60, NUMBER 3

Letters 521

or other tissues (somatic mosaicism).3,4 In the pre-sent case, the pattern of mosaicism is difficult toclassify because mosaicism of adipocytes, which aremesodermal not ectodermal tissue, is currently notwell understood. It is very likely, however, that thistype of segmental lipodystrophy reflects mosaicism.Investigating genes known to cause inherited, sys-temic lipodystrophies (eg, AGTAT2, seipin, LMNA,PPAR-g, and ZMPSTE24) could aid in proving agenetic basis of mosaicism in the present unclassifiedsegmental lipodystrophy. However, we were unableto perform this genetic studies because our patientrefused further evaluation.

Minjeong Kim, MD, Yoonseok Oh, MD, Seung PhilHong, MD, Soo-Young Jeon, MD, and Won-SooLee, MD, PhD

Department of Dermatology, Institute of Hair andCosmetic Medicine, Yonsei University WonjuCollege of Medicine, Wonju, Korea

CASE

Erosive pustular dermatosis of the scalpfollowing topical methylaminolaevulinatephotodynamic therapy

To the Editor: Erosive pustular dermatosis of thescalp (EPDS) is a rare inflammatory disease ofunknown etiology that usually occurs in the elderly.It is characterized by sterile pustules, chronic crustederosions, cicatricial alopecia, and skin atrophy.

A 93-year-old, otherwise healthy female pre-sented to our department with a 2-month history oferoded, pustular, and crusted lesions limited to thescalp. According to the referral notes, she had longstanding female-type androgenetic alopecia, andhad actinic keratoses on the scalp that were treatedwith two sessions of topical methylaminolaevulinatephotodynamic therapy (MAL-PDT), with improve-ment of the condition. The patient had superficialcurettage of the lesions before the first session,followed by the application of methylaminolaevu-linate cream (Metvix; Galderma, Fort Worth, TX) for3 hours under an occlusive, light-protecting dress-ing; the area was then irradiated with 75 J/cm2 ofred light. The photodynamic therapy was repeated1 week later. Twenty-eight days after the firsttreatment, burning erosions developed, extendingslowly but progressively. Treatment with topicalantibiotics (fusidic acid cream and mupirocin) and

Funding sources: None.

Conflicts of interest: None declared.

Correspondence to: Won-Soo Lee, MD, PhD, Depart-ment of Dermatology, Yonsei University WonjuCollege of Medicine, 162 Ilsan-Dong, Wonju,220-701, Korea

E-mail: leewonsoo@yonsei.ac.kr

REFERENCES

1. Garg A. Acquired and inherited lipodystrophies. N Engl J Med

2004;350:1220-34.

2. Agarwal AK, Garg A. Genetic basis of lipodystrophies and

management of metabolic complications. Ann Rev Med

2006;57:297-311.

3. Frank J, Happle R. Cutaneous mosaicism: right before our eyes.

J Clin Invest 2007;117:1216-9.

4. Paller AS. Piecing together the puzzle of cutaneous mosaicism.

J Clin Invest 2004;114:1407-9.

doi:10.1016/j.jaad.2008.06.021

LETTERS

systemic antibiotics (amoxicillin/clavulanate) wasunsuccessful.

The physical examination revealed multiple pus-tules, erosions, scales, and crusts on the frontopari-etal and temporoparietal scalp; gentle removal of thecrusts revealed a moist, atrophic surface with tele-ngiectasias and minute erosions exuding yellowishseropurulent material. Areas of scarring alopeciawere also evident (Fig 1). The remainder of theskin examination was essentially normal, with nofeatures of a blistering disorder or psoriasis. No

Fig 1. Clinical appearance of the scalp: diffuse crustingassociated with multiple pustular, exudative, and erosivelesions.