Case for diagnosis. Single-digit clubbing,

AnBrasDermatol.2020;95(4):524---526

Anais

Brasileiros

de

Dermatologia

WHAT

IS

YOUR

DIAGNOSIS?

Case

for

diagnosis.

Single-digit

clubbing

夽,夽夽

Larissa

Crestani

,

Isaura

Azevedo

Fasciani

,

Priscila

Kakizaki

,

Neusa

Yuriko

Sakai

Valente

DepartmentofDermatology,HospitaldoServidorPúblicoEstadualdeSãoPaulo,SãoPaulo,SP,Brazil

Received20September2019;accepted19January2020

Availableonline11May2020

KEYWORDS

Connectivetissue;

Fingers;

Solitaryfibrous

tumors

Abstract A58-year-oldfemalepatientpresentedwithasingle-digitclubbingonthesecond fingerofherrighthandtwoyearspreviously.Afterinvestigationwithimagingandincisional biopsy,superficialacral fibromyxoma wasdiagnosed. A briefreviewon single-digitclubbing anditscausesispresented,focusingonsuperficialacralfibromyxoma.

©2020SociedadeBrasileiradeDermatologia.PublishedbyElsevierEspa˜na,S.L.U.Thisisan openaccessarticleundertheCCBYlicense(http://creativecommons.org/licenses/by/4.0/).

Case

report

A58-year-old hypertensive womanreported aprogressive increaseinvolumeinthedistalphalanxofthesecondright finger for two years, asymptomatically. On examination, shepresentedhypertrophyofthedistalphalanxassociated with increased nail bed convexity, suggesting single-digit clubbing (Figs. 1 and 2 ) and confirmed by the profile angle andphalangeal depthratio.1 _{Nuclear magnetic}

res-onance showed a nodularformation onthe dorsal aspect ofthedistalsegmentofthefinger,locatedsuperficiallyto thephalanx,causingadjacentboneremodeling,measuring 1.8×1.3×1.0cm and causing bulging of the skin surface (Fig.3).Lesionbiopsywasperformed(Fig.4).

夽 _{How to cite this article: Crestani L, Fasciani IA, Kakizaki P,}

ValenteNYS.Casefordiagnosis.Single-digitclubbing.AnBras Der-matol.2020;95:524---6.

夽夽_{StudyconductedattheHospitaldoServidorPúblicoEstadual}

deSãoPaulo,SãoPaulo,SP,Brazil.

∗_{Correspondingauthor.}

E-mail:laricrestani@hotmail.com(L.Crestani).

Figure1 Increasedvolumeofthesecondfingerintheright hand.

https://doi.org/10.1016/j.abd.2020.01.006

0365-0596/©2020SociedadeBrasileiradeDermatologia.PublishedbyElsevierEspa˜na,S.L.U.ThisisanopenaccessarticleundertheCC BYlicense(http://creativecommons.org/licenses/by/4.0/).

Single-digitclubbing 525

Figure2 Hypertrophyofthedistalphalanxassociatedwithincreasednailbedconvexity.

Figure3 Nodularformationonthedorsalsurfaceofthedistalsegmentofthefinger,locatedsuperficiallytothephalanx,causing adjacentboneremodelingandbulgingtheskinsurface.

Figure4 (A)Dermalproliferationofspindleand stellatecells withoutatypia,immersed inamyxoidstroma withmoderate proliferationofsmallvessels.(B)Greatermagnificationshowingthestellatecells.(C)Positiveimmunohistochemistryexam for CD34.(D)Positiveimmunohistochemistryexamforvimentininthecytoplasmofallcells.

Whatisyourdiagnosis?

A. Enchondroma B. Osteoidosteoma C. Myxoidcyst

D. Superficialacralfibromyxoma

Discussion

Histopathologyassessment showeddermal proliferationof spindleandstellate cells withoutatypia, within amyxoid stroma withmoderate proliferation of smallvessels, sug-gestive of neurofibroma or superficial acral fibromyxoma

526 CrestaniLetal. (SAFM). Immunohistochemistry assessment was requested

todistinguish between the twotumors; cells positive for vimentin, CD34, and KI-67 (1%), and negative for S-100 (Fig. 4) were observed. Negativity for S-100 protein and positivityforCD34favoredthediagnosisofSAFM.

Digital clubbingis characterized by a focalincrease in theterminalsegments ofthefingers duetothe prolifera-tionofconnectivetissuebetweenthenail matrixandthe distalphalanx.Forconfirmation,itisrecommendedto cal-culatetheprofileangle,whichshouldbegreaterthan180◦, andtheratioofthedepthofthedistalphalanxtothe inter-phalangealjoint,whichshouldbegreaterthan1.1,2

Single-digitclubbingisararecondition,usuallycausedby anexpansiveprocessinthedistalphalanx.Enchondromas, osteoidosteoma,myxoid cyst,and myxochondromashave beendescribedasthecauseofthiscondition.2_Tothebest

oftheauthors’knowledge,theliteraturepresentsonlyone caseofsingle-digitclubbingduetoSAFM.3

SAFMisarareandbenignsofttissuetumor,usuallywith slowandpainlessgrowth.Itusuallyaffectstheperiungual and subungual regions of the fingers and toes. Its radio-graphicfindingsarenonspecific.4,5

Histologically, there is dermal or subcutaneous prolif-eration of fusiform and stellate cells within a myxoid, mixoid-collagenous,orcollagenousmatrix,withprominent microvasculatureandmastcellinfiltrate.Mildnuclear atyp-ias and mitoses may be observed. Immunohistochemistry assessments are positive for CD34, CD99, vimentin, and CD10,andnegativeforS-100.4---8

Differentialdiagnosesincludemyxoidtumorsandthose thataffectthedistalpartofthelimbs,suchas dermatofi-brosarcoma protuberans, myxoid neurofibroma, fibrous histiocytoma,acquireddigitalfibrokeratoma,acral myxoin-flammatoryfibroblasticsarcoma, sclerosing perineurioma, superficial angiomyxoma, and low-grade fibromyxoid sar-coma, in addition to the previously mentioned causes of single-digitclubbing.4,7---9

Inacquireddigitalfibrokeratoma,CD34maybepositive, butitdiffershistopathologically,asitpresentspronounced hyperkeratosis and acanthosis, low cellularity, and thick collagen bundles parallel to the long axis of the lesion. Low-gradefibromyxoidsarcomaisnegativeforCD34,unlike SAFM,whichispositive.10

Treatmentconsistsofcompleteexcisionofthelesion.4,5,7

Thepatientoptedforclinicalfollow-updue tothebenign natureofthelesion.

Financial

support

Nonedeclared.

Authors’

contributions

Larissa Crestani: Approval of the final version of the manuscript; elaboration and writing of the manuscript;

intellectualparticipationinpropaedeuticand/or therapeu-ticconductofstudiedcases;criticalreviewoftheliterature; criticalreviewofthemanuscript.

IsauraAzevedoFasciani:Criticalreviewoftheliterature; criticalreviewofthemanuscript.

Priscila Kakizaki: Approval of the final version of the manuscript;intellectual participationin propaedeutic and/ortherapeuticconductofstudiedcases;criticalreview oftheliterature;criticalreviewofthemanuscript.

NeusaYurikoSakaiValente:Approvalofthefinalversion ofthemanuscript;intellectualparticipationinpropaedeutic and/ortherapeuticconductofstudiedcases;criticalreview oftheliterature;criticalreviewofthemanuscript.

Conflicts

of

interest

Nonedeclared.

References

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4.FetschJF,LaskinWB,MiettinenM.Superficialacral fibromyx-oma:aclinicopathologicandimmunohistochemicalanalysisof 37casesofadistinctivesofttissuetumorwithapredilection forthefingersandtoes.HumPathol.2001;32:704---14. 5.Ashby-Richardson H, Rogers GS, Stadecker MJ. Superficial

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10.BillingsSD,GiblenG,Fanburg-SmithJC.Superficiallow-grade fibromyxoidsarcoma(Evanstumor):aclinicopathologicanalysis of19caseswithauniqueobservationinthepediatric popula-tion.AmJSurgPathol.2005;29:204---10.