Sebaceoma on the scalp simulating a malignant pigmented neoplasia

AnBrasDermatol.2019;94(5):590---593

Anais

Brasileiros

de

Dermatologia

DERMATOPAHOLOGY

Sebaceoma

on

the

scalp

simulating

a

malignant

pigmented

neoplasia

夽,夽夽

Bárbara

Catojo

Poggi

_,

_Daniel

_Fernandes

_Melo

_,

_Juliana

_Marques

_da

_Costa

_,

Maria

Auxiliadora

Jeunon

Sousa

a_{DepartmentofDermatology,HospitalNavalMarcílioDias,RiodeJaneiro,RJ,Brazil}

b_{PostgraduatePrograminMedicalSciences,HospitalUniversitárioPedroErnesto,UniversidadedoEstadodoRiodeJaneiro,Rio}

deJaneiro,RJ,Brazil

c_{ClinicofOncologicDermatologyandDermatoscopy,DepartmentofDermatology,HospitalNavalMarcílioDia,RiodeJaneiro,RJ,}

Brazil

d_{ID--- Investigac¸ãoemDermatologia,RiodeJaneiro,RJ,Brazil}

Received10July2018;accepted19December2018

KEYWORDS Adenoma; Dermoscopy; Histology; Melanoma; Neoplasms; Sebaceousgland neoplasms; Sebaceousglands; Skinneoplasms; Trichoscopy

Abstract Thecorrectidentificationofpigmentednodularlesionsofthescalpisoften challeng-ing.Despitetheimportanceofclinicalpatternsanddermoscopy,importantadjuvanttoolsthat areusuallyhelpful,theirinterpretationsometimesisnotclear-cut.Here,theauthorsdiscussa caseofsebaceomamimickingamalignantpigmentedneoplasia,withconclusivehistopathology. ©2019PublishedbyElsevierEspa˜na,S.L.U.onbehalfofSociedadeBrasileiradeDermatologia. ThisisanopenaccessarticleundertheCCBYlicense(http://creativecommons.org/licenses/ by/4.0/).

Introduction

Diagnosisofpigmentednodularlesionsofthescalpisoften challenging.Clinicalfindingsanddermoscopyareimportant

夽 _{Howto citethisarticle: PoggiBC, Melo DF,Costa JM,Sousa}

MAJ.Sebaceomaon thescalpsimulating a malignantpigmented

neoplasia.AnBrasDermatol.2019;94:590---3.

夽夽_{StudyconductedattheHospitalNavalMarcílioDias, Riode}

Janeiro,RJ,Brazil.

∗_{Correspondingauthor.}

E-mail:[email protected](B.C.Poggi).

in the suspicion of malignant melanocytic lesions; never-theless, histopathology maintains its fundamental role in diagnosticconclusion,sinceotherlesionscanmimicthem.

Case

report

An 80-year-old female patient, Fitzpatrick phototype II, with a history of endometrial cancer, developed a black, nodular,andasymptomatic lesion witherythematousbase and central crust on the vertex of her scalp (Fig. 1). Dermoscopyshowedayellowisherythematousarea,yellow globules,hematiccrust,ared-milkyarea,andpolymorphic https://doi.org/10.1016/j.abd.2019.09.007

0365-0596/©2019PublishedbyElsevierEspa˜na,S.L.U.onbehalfofSociedadeBrasileiradeDermatologia.Thisisanopenaccessarticle

Sebaceomaonthescalpsimulatingamalignantpigmentedneoplasia 591

Figure1 Blackenednoduleuponerythematousbasewith cen-tralcrustattheapexofthescalp.

Figure2 Hematic crustandperipheralred-milkyarea with poorlydefinedglobulesondermoscopy.

vessels,suggestingseborrheickeratosis,anadnexaltumor, oratraumatizedmelanocyticnevus(Fig.2).Thepresence ofawhitishveil,abrightwhitearea,asymmetricfollicular openings,andrhomboidalstructuresdidnotallowexclusion of cutaneousmelanoma (Fig.2).An excisional biopsywas performed andhistopathological examination evidenced a circumscribed proliferation of large basaloid cell masses and sebaceous cells, with the diagnostic conclusion of sebaceoma.

Discussion

Sebaceoma has been called sebomatrixoma or sebaceous epithelioma, when the use of the term epithelioma sug-gestedmalignancy.ClassifiedbyTroyandAckermanin1984 as a benign neoplasm with sebaceous differentiation, it moreoftenaffectswomen,withpredominanceintheeighth decadeoflife.1

Clinically,itappearsasayellowishororange,solitary,or rarelymultiplehemisphericexophytictumorlocatedinthe seborrheicareasofthebody,especiallyonthescalp.1,2

Dermoscopy of sebaceoma may present an amorphous yellowish-erythematous area with or without ulcerations, withcentripetallybranchedarboriformvessels.The amor-phous yellowish-erythematous area may be an important findingsuggestingthesebaceousetiologyofthelesion.3,4

Severalbenign adnexaltumorsmaypresent asasingle nonspecificlesion;therefore,histopathologicalexamination isfundamentalfordefinitivediagnosis.Therearetumorsfor which no malignancy is suspected because they lie more deeply in the dermis and may resemble cysts. However, onseveral occasions,benigntumorsareconnectedtothe epidermis or touch it, with the possibilitythat traumatic ulcerationsandtherebymalignanciescanbemimicked.5,6

Benignandmalignanttumorsareidentifiedbythetype ofdifferentiationtheyexhibit,theremnantsoftheirorigin cells,althoughmalignanttumorslacktherichnessoffindings thatbenignvariantsshow.Regardingsebaceoustumors,the signsofdifferentiation aresebaceous cells andsebaceous ducts(Fig.3).5

Sebaceousglandsarecomposedofseverallobesleading toaductconnectedtothehairfollicle.Thereisaperipheral singlerowofundifferentiatedcellsand,towardthecenter, cellswithincreasingdegreesof differentiationbyfat syn-thesisuntilthewell-differentiated sebocytesinwhichthe nucleusisindentedbyvariousdepressionscausedbylarge fatvacuoles.Neartheduct,thesebaceouscellslosetheir nuclei,andthusthesebaceoussecretionknownasholocrine iseliminated.

Sebaceomas are constituted by masses located in the dermis,connectedor unconnected totheepidermis, with histologicalarchitecture that suggests benignity: rounded contours, a greater vertical axis, and symmetry, differ-ent from the sebaceous carcinomas despite the possible presenceofmitosis(Fig.3).Theyarecomposedof undiffer-entiatedcellsandcellswithdifferentdegreesofsebaceous differentiation. The absence of peripheral palisade and clefts between the aggregates and the stroma distin-guish them from basal cell carcinomas with sebaceous differentiation.5,6

Figure3 Pathologicalfeaturesofsebaceoma.Regularly con-toured epithelial neoplasia arranged in ‘‘v’’ with the apex pointing toward the depth. There is acanthosis on the left andpredominanceofdermalmassesonthe right,conferring intrinsicasymmetry, anunusualcharacteristicforthistypeof proliferation.The masseshaveregular shapesandsizes, are predominantlyroundedor oval, andareimmersed in collag-enizedstroma.In this panoramicmagnification,itis already possibletoperceive clusters ofepithelial cells ofpale cyto-plasmpermeatingthemasses;thisisrepresentativeofmature sebocytes(Hematoxylinandeosin,×20).

592 PoggiBCetal. What differentiate the sebaceous adenoma from

sebaceomaarethecellulararrangementandtheproportion of undifferentiated cells, more numerous in sebaceoma. In sebaceous adenoma, the arrangement of the latter in the periphery of the aggregates and in those with some degreeof differentiation in thecentralportion resembles thenormalsebaceous gland,facilitatingitsidentification. However,unlikethenormalgland,thereareseverallayers of peripheral undifferentiated cells. This proliferation replacestheepidermisanditssecretionisreleasedstraight tothesurface, insteadof draining intothe follicularunit throughthesebaceousductwherethesebaceoussecretion ofthenormalglandreachesthesurface.

In sebaceoma, with the two types of cells arranged in a disordered way, the search for sebocytes withmore advanced differentiation --- and they may be sparse --- is necessary.Incontrast,thesebaceousducts, absentinthe adenomas,are present in the sebaceomas andserve asa cluefortheactivesearchofsebocytes.

Although thesebaceous adenomahasthe architectural andcytologicalcharacteristicsclosesttothenormalgland, someauthorsconsidered itasasecond typeofsebaceous carcinomaduetopresenceofcellstackingandmitotic fig-uresinundifferentiatedperipheralcells.6,7

Thedistinctionbetweenbenignandmalignantneoplasms considersthedegreeofdifferentiation,withthemalignant neoplasmshavinglowerdegrees,sincethecellular appara-tusis gearedtoward celldivisionratherthansynthesizing substancesinvolvedindifferentiation.Advanced differenti-ationandmalignityareopposingconcepts(Fig.4).6

Itispossibletosupposethatthesecretionofsebaceous adenomas,beingfreelyeliminatedonthesurface,doesnot suffer the effect of a retrograde compression, as should occurwiththepassageofsebumthroughanarrowductin thenormalgland.Itisaspeculationtoconcludethat secre-tionretaineduntilitseliminationisafactorthatinhibitscell divisionandthatitsabsenceinsebaceousadenomasfavors

Figure 4 Pathological features of sebaceoma. Detail of epithelialmassivearrangedinthedermis.The predominance ofvesicle-likeepithelialcellsandscarcecytoplasm(immature sebocytes) can be noted, which areless permeated by pale cytoplasmcells,containinglipidvacuoles,somewithindented nuclei(maturesebocytes),randomlyarrangedandassociated withducts.Thereisabsenceofpalisadeintheperipheryofthe masses(hematoxylinandeosin,×200).

Figure 5 Immunohistochemical staining oftheskin biopsy: positivity intheimmunohistochemicalreactionwiththe anti-EMAantibodyinacytoplasmicreticularpatternaroundthelipid vacuoles(originalmagnificationof_×400).

cellproliferation.It isimportanttorememberthatin the bulbs of anagenic follicles, producing a hair shaft contin-uouslyat areasonable rate,cellstacking andmitosisalso occur.

Immunohistochemicalstudy insebaceomashows multi-focal positivity of the neoplastic cells with anti-CK7 and anti-EMAantibodies, andnegativityinreactions with anti-CK20andanti-BerEp4antibodies(Fig.5).

Presence of neoplasms with sebaceous differentiation or multiple keratoacanthomas may be revealing of Muir-Torre Syndrome, which alsohas visceral adenocarcinomas located mainly in the gastrointestinal and genitourinary tracts,endometrium,andlarynx.Itpredominantly affects men in the fifth decade of life, and clinical screening is mandatory,asinthecaseofthepatientinquestion.8,9

Final

considerations

The diagnosis ofpigmentednodularlesionsofthe scalpis challenging. Dermoscopyis an excellenttool for the defi-nitionofthesecases,havingwell-establishedstandardsfor thediagnosisofneoplasms,pigmentedornot.However,as in the case reported, thehistopathological study remains the gold standard for diagnosis, and wasfundamental for theelucidationofthesebaceousnaturedescribedabove.

Financial

support

Nonedeclared.

Author’s

contributions

Bárbara Catojo Poggi: Elaboration and writing of the manuscript;obtaining,analyzingandinterpretingthedata. Daniel Fernandes Melo: Approval of the final version of the manuscript;conception andplanning of the study; elaborationandwritingofthemanuscript;intellectual par-ticipation in propaedeutic and/or therapeutic conduct of thecasesstudied;criticalreviewofthemanuscript.

Sebaceomaonthescalpsimulatingamalignantpigmentedneoplasia 593 JulianaMarquesdaCosta:Approvalofthefinalversionof

themanuscript;elaborationandwritingofthemanuscript; intellectualparticipationinpropaedeuticand/or therapeu-tic conduct of the cases studied; critical review of the manuscript.

Maria Auxiliadora Jeunon Sousa: Approval of the final version of themanuscript; elaboration and writing of the manuscript;effectiveparticipationinresearchorientation; intellectualparticipationinpropaedeuticand/or therapeu-tic conduct of t.he cases studied; critical review of the literature;criticalreviewofthemanuscript.

Conflicts

of

interest

Nonedeclared.

Acknowledgements

WewouldliketothankDr.ThaisRobertaUraGarciaandDr. ThiagoJeunon deSousaVargas,whose contributionswere fundamentaltotheconclusionofthearticle.

References

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