Table Of ContentdasChagaseSilvadeCarvalhoetal.BMCResearchNotes2013,6:30
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CASE REPORT Open Access
Immunohistochemical features of multifocal
melanoacanthoma in the hard palate: a case
report
Luis Felipe das Chagas e Silva de Carvalho1,2, Vitor Hugo Farina1, Luiz Antonio Guimarães Cabral1,
Adriana Aigotti Haberbeck Brandão1, Ricardo Della Coletta3 and Janete Dias Almeida1,4*
Abstract
Background: Melanoacanthoma (MA) has been described inthe oral mucosa as a solitary lesion or, occasionally, as
multiple lesions. MA mainly affects dark skinned patientsand grows rapidly, showing a plane or slightly raised
appearance and a brown to black color. The differential diagnosis includes oral nevi, amalgam tattoos, and
melanomas. We report here the case of a 58-year-old black woman who presented multiple pigmented lesionson
thehard palate.
Case presentation: Based onthe differential diagnosis of melanoma, a punch biopsy (4mm indiameter)was
performed. The material was fixed in10% formalin, embedded inparaffin, and stained with hematoxylin-eosin or
submitted to immunohistochemical analysis. Immunohistochemistry using antibodies against protein S-100, melan-
A,HMB-45, MCM-2, MCM-5, Ki-67and geminin was performed.Immunohistochemical analysis revealed strong
cytoplasmic immunoreactivity ofdendritic melanocytes for proteinS-100,HMB-45 and melan-A.Positivestaining for
proliferative markers (MCM-2, MCM-5, Ki-67) was onlyobserved inbasal and suprabasal epithelial cells, confirming
thereactive etiologyof the lesion. The diagnosis was oral Melanoacanthoma (MA).
Conclusion: The patient has been followed up for 30 months and shows noclinical alterations. MA should be
included inthedifferential diagnosis of pigmented lesions ofthe oral cavity.
Keywords: Melanoacanthoma,Mouth, Pigmentedlesions
Background Thefirstreportof oralMAwaspublished bySchneider
Inanattempttobetterdefinethemelanoepitheliomatypes and coworkers (1981) [3]. Since then, MA has been
1 and 2 described by Bloch (1937), Mishima & Pinkus described in the oral mucosa as a solitary lesion or, occa-
(1960) were the first to use the term melanoacanthoma sionally, as multiple lesions [2]. MA mainly affects dark
(MA)[1].Accordingtotheseauthors,MAcorrespondsto skinned patients and grows rapidly, showing a plane or
Bloch’s melanoepithelioma type 1, a rare variant of pig- slightlyraisedappearanceandabrowntoblackcolor.The
mentedseborrheickeratosischaracterizedbytheprolifera- differential diagnosis includes oral nevi, amalgam tattoos,
tion of melanocytes and keratinocytes in the lower layers and melanomas [4-8]. Histologically, MA is characterized
oftheepithelium[2]. by the proliferation of sparse melanocytes throughout the
epithelium and epithelial spongiosis. An increase in the
numberofmelanocytesinthebasallayerandthepresence
of a chronic submucosal inflammatory infiltrate contain-
*Correspondence:[email protected] ing eosinophils are also observed [4-7]. These findings
1DepartmentofBiosciencesandOralDiagnosis,SãoJosédosCamposDental
suggest the possible activation of melanocytes by an un-
School,SãoPauloStateUniversity(UNESP),SãoJosédosCampos,SãoPaulo,
Brazil known mechanism that could be the link between a mel-
4FaculdadedeOdontologiadeSãoJosédosCampos–UNESP, anotic macule and MA and would be a reactive rather
DepartamentodeBiociênciaseDiagnósticoBucal,Av.FranciscoJoséLongo,
thanaphysiologicalprocess.
777SãoDimas,12245-000,SãoJosédosCampos,SãoPaulo,Brazil
Fulllistofauthorinformationisavailableattheendofthearticle
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Figure1A,Photographshowingtheclinicalappearanceofthelesion.B,Lesionafterincisionalbiopsy.
The objectives of the present study were to report a in size during this period and presented discrete itching
case of multifocal MA in the hard palate and to high- whentouchedbythetongue.
light the main differential diagnoses and immunohisto- Clinically, the lesions appeared as spots with imprecise
chemicalfindings. borders,hadabrowntodarkbrowncolor,andpresenteda
tendency towards nodule formation (Figure 1). Radiogra-
Case presentation phy was non-contributory. Based on the differential diag-
A 58-year-old black woman sought the Stomatology Out- nosis of melanoma, a punch biopsy (4 mm in diameter)
patient Clinic of the São José dos Campos Dental School was performed. The material was fixed in 10% formalin,
in March 2008 because of a “blood stain on the roof of embedded in paraffin, and stained with hematoxylin-eosin
hermouth”(sic).Thepatientusedaremovableupperden- or submitted to immunohistochemical analysis [9,10].
ture and had noted the presence of black-brownish spots Histopathological analysis revealed a mucosal fragment
onthehardpalate3monthsago.Thespotshadincreased lined with hyperorthokeratinized stratified pavement
Figure2Histopathologicalappearanceofmelanoacanthomastainedwithhematoxylin-eosinatdifferentmagnifications(A:100x;B:
200x;C:400x)andstainedwithperiodicacidSchiffat200xmagnification(D).
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epithelium. The epithelium exhibited mild acanthosis and
melanin pigmentation in the basal layer. Several dendritic
melanocytes were observed in the spinous layer and me-
lanin pigment was present in the cytoplasmic processes
interposed with keratinocytes. In the lamina propria con-
sisting of fibrous connective tissue, melanophages were
present in the juxtaepithelial region and a scarce and dif-
fuse mononuclear inflammatory infiltrate was noted. In
view of the histopathological findings, a diagnosis of MA
wasmade(Figure2).
Immunohistochemistry using antibodies against pro-
tein S-100, melan-A, HMB-45, MCM-2, MCM-5, Ki-67
and geminin was performed for a better understanding
of oral MA. Reactivity for protein S-100 was observed in
Langerhans cells, melanocytes and some cells of the
underlying submucosa. Immunostaining of HMB-45 and
melan-A was only detected in melanocytes, with the ob-
servation of a larger number of HMB-45-positive cells.
Anti-Ki-67, anti-MCM-2 and anti-geminin antibodies
only reacted with cells of the basal and suprabasal layers
oftheepithelium,whereasMCM-5stainingwasnegative
(Figures 3and4).
The biopsy region healed normally and no new inter-
vention was necessary. The patient has been followed up
for30 months andshows noclinical alterations.
ManytermshavebeenproposedforMA,includingmela-
nocyticreactivehyperplasiaandmucosalmelanoticmacule,
reactive type [4-7]. In a literature review, Fornatora et al.
(2003) [11] analyzed 28casesofMA andobserved amean
patientageof27.9years(range:9to54years).Twenty-five
(89.3%) of the 28 patients were black and there was a fe-
male preference (female:male ratio of 2.1:1). Although the
cheek mucosa was the site most commonly affected (18 of
28 cases), MA occurred at other sites such as lip mucosa,
lowerlip,palate,gingiva,alveolarmucosa,andoropharynx.
Thesizeofthelesions,ifreported,rangedfrom0.3to5cm
in maximum diameter. MA presented as a smooth or
slightlyraised,hyperpigmented(browntoblack)lesionthat
rapidly reached various centimeters. Traditionally, MA is
asymptomatic but pain, a burning sensation and itching
have been reported [4-8]. The present patient reported
discreteitchingupontouch. Figure3Immunostainingformelan-Aatthreedifferent
MA is believed to be a reactive lesion that typically magnifications.
affectsmucosalsurfacessusceptibletotraumaandrapidly
develops after an episode of acute trauma or at a site of
chronic mucosal irritation [4-8]. The rapid growth, reso- case, including rapid progression of the lesion, color, ir-
lution after incomplete removal, and the presence of an regularcontours,andtendencytowardsnoduleformation.
inflammatoryinfiltrateintheunderlyingconnectivetissue Although Kaposi´s Sarcoma is common in hard palate it
support the reactive nature of MA. This fact explains the was not considered in our diagnostic hypothesis. The al-
higher incidence of MA in mobile mucosa vulnerable to gorithm proposed by Kauzman et al. (2004) [12] to guide
trauma (e.g., cheek mucosa, lip mucosa, and palate). In the assessment of pigmented lesions of the oral cavity on
the present case, the patient used a removable mucosa- the basis of history, clinical examination and laboratory
supported upper denture. The diagnostic hypothesis was investigations includes Kaposi´s Sarcoma in the group of
melanoma considering the clinical characteristics of the diffuse and bilateral pigmentation with predominantly
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Figure4Immunostainingforgeminin(A),Ki-67(B),MCM-2(C),andMCM-5(D).
adult onset. Early lesions of Kaposi´s Sarcoma appear as histological diagnosis of MA is established, no further
flat or slightly elevated brown to purple lesions and the investigation is required since there are no reports of
advanced ones may appear as dark red to purple plaques malignanttransformationofMA[8].
or nodules that may exhibit ulceration, bleeding and ne- The present histopathological findings showing no
crosis[12]. sign of malignancy agree with reports in the literature.
Histologically, MA is characterized by the proliferation Although some investigators emphasize the frequent oc-
of melanocytes in the basal layer and by the presence of currence of a heterogeneous inflammatory infiltrate in
strongly pigmented dendritic melanocytes throughout cases of MA [10], the present patient presented a scarce
the acanthotic epithelium. The presence of large den- anddiffusemononuclearinflammatory infiltrate.
dritic melanocytes in the superficial portions of the epi- Immunohistochemical analysis was performed inorder
thelium is the cause of the histological resemblance with to better understand the etiology and behavior of MA.
melanoma, particularly acral lentiginous melanoma. In For this purpose, specific markers of cellular elements
the latter case, atypical pigmented dendritic melanocytes that might be compromised during the genesis of the
are irregularly distributed in the acanthotic epithelium disease and cell proliferation markers were used. Epithe-
and atypical non-dendritic melanocytes may proliferate lial cells stained positive for protein S-100, demonstrat-
along the basal layer (lentiginous proliferation). This ing the involvement of cells of neuroectoderm origin in
type of melanoma can also exhibit a dense subepithelial the etiology of MA [9]. Protein S-100 shows a sensitivity
lymphocyticinfiltrate [5,13-15]. of 97 to 100% for the detection of melanoma. However,
According to Goode et al. (1983) [13], the inflamma- the specificity of this protein for melanocytic lesions is
tory infiltrate in MA exhibits eosinophilia associated limited, with this marker also being expressed on neu-
with increased vascularization and mild chronic inflam- ral cells, myoepithelial cells, adipocytes, chondrocytes,
mation. Cases of MA usually present a slight increase of Langerhans cells, and in tumors arising from these cells
vascularization and a chronic heterogeneous inflamma- [10]. Melan-A, a marker that recognizes normal melano-
tory infiltrate in connective tissue. In MA, melanin is cytes as well as antigens present on melanomas, was
generally restricted to melanocytes, whereas adjacent detected in the present study in some epithelial cells.
keratinocytes contain no pigment. In the case of other Likewise,HMB-45,amelanoma marker,alsostainedepi-
hyperpigmented lesions such as oral melanotic macule thelial cells but to a lesser extent than melan-A. Staining
and physiological pigmentation, melanin is transferred for Ki-67, MCM-2 and geminin was only detected in
from dendritic epidermal melanocytes to epidermal ker- cells of the basal and suprabasal layers of the epithelium.
atinocytes that form the epidermal melanin. Once the Since these proteins are markers of cell proliferation,
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theymightberesponsiblefortheacanthoticphenomenon References
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forpublicationofthiscasereportandanyaccompanying
doi:10.1186/1756-0500-6-30
images. A copy of the written consent is available for re- Citethisarticleas:dasChagaseSilvadeCarvalhoetal.:
view bytheEditor-in-Chiefofthisjournal. Immunohistochemicalfeaturesofmultifocalmelanoacanthomainthe
hardpalate:acasereport.BMCResearchNotes20136:30.
Competinginterests
Theauthorsdeclarethattheyhavenocompetinginterests.
Authors’contribution
LFCSC,VHF,LAGCandJDAexaminedthepatient.LFCSCandVHFcarried
outthebiopsy.JDAdraftedthemanuscript.RDCandAAHBparticipatedin
thedesignofthemanuscript.AAHBperformedthehistologicalexamination.
RDCperformeddeimmunohistochemistry.LACGconceivedthemanuscript,
andparticipatedinitsdesignandcoordination.Allauthorsreadand
approvedthefinalversionofthemanuscript. Submit your next manuscript to BioMed Central
and take full advantage of:
Authordetails
1DepartmentofBiosciencesandOralDiagnosis,SãoJosédosCamposDental
• Convenient online submission
School,SãoPauloStateUniversity(UNESP),SãoJosédosCampos,SãoPaulo,
Brazil.2NanosciencesandAdvancedMaterials,FederalUniversityofABC, • Thorough peer review
SantoAndré,SãoPaulo,Brazil.3DepartmentofOralDiagnosis,OralPathology • No space constraints or color figure charges
Division,PiracicabaDentalSchool,UniversityofCampinas,Piracicaba,São
Paulo,Brazil.4FaculdadedeOdontologiadeSãoJosédosCampos–UNESP, • Immediate publication on acceptance
DepartamentodeBiociênciaseDiagnósticoBucal,Av.FranciscoJoséLongo, • Inclusion in PubMed, CAS, Scopus and Google Scholar
777SãoDimas,12245-000,SãoJosédosCampos,SãoPaulo,Brazil.
• Research which is freely available for redistribution
Received:21September2012Accepted:24January2013
Published:28January2013 Submit your manuscript at
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