Hong Kong J. Dermatol. Venereol. (2016) 24, 87-91

Case Report

Subungual blue naevus presenting with elkonyxis

S Do an, N Atakan, H Khurami, O Gökoz, O Bitik

Common blue naevi usually occur on the skin however subungual blue naevi are extremely rarepigmented lesions of the nail. They need to be differentiated from pigmentations, chromogenicnail diseases, infections and most importantly melanoma. Herein, a 39-year-old female patientwith subungual blue naevus who presented together with elkonyxis is presented with a brief reviewof cases from the literature.

Keywords:Keywords:Keywords:Keywords:Keywords: Blue naevi, elkonyxis, melanoma, nail, subungual

Department of Dermatology and VDepartment of Dermatology and VDepartment of Dermatology and VDepartment of Dermatology and VDepartment of Dermatology and Venereologyenereologyenereologyenereologyenereology,,,,,Hacettepe University Faculty of Medicine, SHacettepe University Faculty of Medicine, SHacettepe University Faculty of Medicine, SHacettepe University Faculty of Medicine, SHacettepe University Faculty of Medicine, SlllllhhhhhhhhhhlllllyeyeyeyeyeAnkAnkAnkAnkAnkara Tara Tara Tara Tara Turkurkurkurkurkeyeyeyeyey

S Do an, MD, MscN Atakan, MDH Khurami, MD

Department of PDepartment of PDepartment of PDepartment of PDepartment of Pathologyathologyathologyathologyathology, Hacettepe University, Hacettepe University, Hacettepe University, Hacettepe University, Hacettepe UniversityFaculty of Medicine, SFaculty of Medicine, SFaculty of Medicine, SFaculty of Medicine, SFaculty of Medicine, Slllllhhhhhhhhhhlllllye Ankye Ankye Ankye Ankye Ankara Tara Tara Tara Tara Turkurkurkurkurkeyeyeyeyey

O Gökoz, MD

Department of Plastic, RDepartment of Plastic, RDepartment of Plastic, RDepartment of Plastic, RDepartment of Plastic, Reconstructive and Aestheticeconstructive and Aestheticeconstructive and Aestheticeconstructive and Aestheticeconstructive and AestheticSurgery, Hacettepe University Faculty of Medicine,Surgery, Hacettepe University Faculty of Medicine,Surgery, Hacettepe University Faculty of Medicine,Surgery, Hacettepe University Faculty of Medicine,Surgery, Hacettepe University Faculty of Medicine,SSSSSlllllhhhhhhhhhhlllllye Ankye Ankye Ankye Ankye Ankara Tara Tara Tara Tara Turkurkurkurkurkeyeyeyeyey

O Bitik, MD

Correspondence to: Dr. S Do an

Hacettepe University Department of Dermatology andVenereology, Ankara Turkey

IntroductionIntroductionIntroductionIntroductionIntroduction

Subungual blue naevi are extremely rarepigmented lesions of the nail which need to bedifferentiated from other conditions like exogenouspigmentations, nail diseases and melanoma.Herein, we report a patient with subungual bluenaevus who presented together with elkonyxis.

Case reportCase reportCase reportCase reportCase report

A 39-year-old Caucasian female patient admittedto the dermatology outpatient clinic with acomplaint of discolouration and deformity on thenail of her left second finger. The blue-purplediscolouration had been present for approximately

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15 years but she had noted mild progression ofits borders lately. The nail plate distal to thediscolouration had become brittle over the past3-4 years with severe splitting and peeling of thenail. There was no previous history of nail traumaand the lesion was slightly tender only iftraumatised or on palpation. There was nopersonal or family history of skin cancer or naildisease.

Dermatological examination of the second leftfingernail showed non-blanching steel bluepigmentation surrounded by a rim of light brownarea and an outer sheath of bony white circularlunula. A triangular pinched-out appearance ofthe nail plate beginning from the base of thelesional distal matrix area was present. Multiple

longitidunal depressions were present in themedian part of the nail which were consistentwith elkonyxis (Figure 1). Under dermatoscopicexamination, the discolouration was seen toextend under the proximal nailfold (Figure 2).18-MHz ultrasound imaging of the nail plate andnailfold showed increased longitidunal curvatureof nail plate with irregularities within dorsal andventral plates, slight thickening of nailbed withincreased hypoechogenicity and vascularitycompared to the right second finger nail. No solidmass was detected (Figure 3). Pigmentation ofsurrounding skin was not present. Although thelesion had been present for 15-year, the recentchanges observed by the patient together with theextension of the lesion under the proximal nailfoldand recent onset of elkonyxis associated with thepigmented lesion led to an excisional biopsy. Thedifferential diagnoses included cellular bluenaevus, melanoma arising form a blue naevusand glomus tumour. His topathologicalexamination of the lesion showed spindle cellproliferation with single dendritic bipolar

Figure 1.Figure 1.Figure 1.Figure 1.Figure 1. Subungual steel blue pigmentation with arim of light brown area and outer circular lunula.Median pinched out elkonyxis with multiple longitidunaldepressions is noted on the nail plate.

Figure 2.Figure 2.Figure 2.Figure 2.Figure 2. Steel blue structureless pigmentation withdark blue lagoon-like areas extending under proximalnailfold, subungual haemorrhagic lines are also notedwithin dystrophic nail plate.

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Figure 3.Figure 3.Figure 3.Figure 3.Figure 3. Irregularities within dorsal and ventral plates of the nail plate, thickening of nailbed with increasedhypoechogenicity and vascularity. pnf: proximal nailfold, nb: nailbed, m: matrix, dph: distai interphalangealjoint.

Figure 4.Figure 4.Figure 4.Figure 4.Figure 4. The lesion in the subepithelial area ischaracterised by spindle cell proliferation with brownpigment in between (H&E x100).

melanocytes in the collagenous stroma withouthypercellularity, atypia or mitoses (Figures 4 & 5).The patient was therefore diagnosed with cellularsubungual blue naevus and elkonyxis.

DiscussionDiscussionDiscussionDiscussionDiscussion

Blue naevi are caused by dermal proliferation ofpigmented melanocytes, these lesions particularlylook blue clinically and are predominantlyobserved blue under dermatoscopy because ofthe Tyndall phenomenon observed in the skinwhere deep located melanin gives a bluish hue.Blue naevi can be observed as flat macules orpapules and typically show a structureless steel-blue colouration without reticular networkdermatoscopically.1 Common blue naevi usuallyoccur on the skin, subungual blue naevus is rarelyseen. Subungual blue naevus was first describedas a component of periungual combined naevusin a patient with Klippel-Trenaunay syndrome whoalso had regional lymphatic involvement of bluenaevus.2 In the literature, reported cases of bluenaevi are also few.3-7 Causeret et al reported a42-year-old female patient with a blue spot on

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her left first toenail. This patient had a phototypeV skin and an ovoid shaped blue pigmentationalong with several longitudinal melanonychia,A 20-MHz ultrasound examination revealed ahomogeneous hypoechogenic subungual bandand the excised lesion was reported as cellularsubungual blue naevus.5 In 2008, Naylor et aldescribed a further case of subungual bluenaevus involving finger nail with a combinedhistopathological phenotype where the lesionis composed of a mixture of variably shapedsmal l round, spindled, and epi thel io idmelanocytes. This case was the first to showcombined histopathological features of bluenaevi as the authors also reviewed reportedsubungual melanocytic naevi in the literatureand concluded that four of the previous caseswere of the common type, the remaining threecases were reported as the cellular type. Theseblue naevi were equally seen in both gendersand involved both finger and toenails.7

Figure 5.Figure 5.Figure 5.Figure 5.Figure 5. (A) There is a Grenz zone between the epithelium and the lesion. Cells are dispersed in the collagenousstroma (H&E x200); (B) Single dendritic bipolar spindle shaped melanocytes in the collagenous stroma.Hypercellularity, atypia or mitoses are not seen. The brown pigment is melanin mostly phagocytosed bymelanophages (H&E x400).

Our case was not congenital but acquired bluenaevus and was a common blue naevushistopathologically. Associated nail plateabnormalities with subungual blue naevus suchas fragility was only reported by Naylor et alwhere the patient complained about brittlenessof the nail.7 Our case presented with a severeinvolvement of the nail plate presenting withelkonyxis. In fact it was the main presentingcomplaint. She also had not iced recentenlargement of the lesion. Expansile growth insubungual blue naevi has been previouslyreported by Lee et al in which there were non-symmetrical black macules on the nail bed withincreasing size corresponding to increasedvertical thickness of benign melanocyteshistopathologically.8

It is crucial to exclude subungual melanoma whendealing with subungual pigmented lesions.Features like Hutchinson's sign, progression of the

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size of the lesion, darkening of the pigmentationand single nail involvement must be carefullyevaluated. Besides the history of lesionalenlargement and nail dystrophy our case wasdiagnosed as subungual cellular blue naevus. Itis important to be aware of the clinical andimaging features of these rare cases to increaseour awareness of both benign and malignantpigmentations of the nail apparatus and betterunderstanding and differentiation of thesediseases.

RRRRReferenceseferenceseferenceseferenceseferences

1. Longo C, Scope A, Lallas A, Zalaudek I, MoscarellaE, Gardini S,et al. Blue lesions. Dermatol Clin 2013;31:637-47.

2. Soyer HP, Kerl H. European Society of Pediatric

Dermatology Clinical Case Reports 1984. In: BaranR, Dawber RPR, Berker DAR, Haneke E, Tosti A (eds).Diseases of the Nails and Their Management, 3rdedn. Oxford: Blackwell Science Ltd, 2001;616-8.

3. Vidal S, Sanz A, Hernández B, Yus ES, Requena L,Baran R. Subungual blue naevus. Br J Dermatol1997;137:1023-5.

4. Moulonguet-Michau I, Abimelec P. Nail unit bluemelanocyte nevi: 2 case reports. Ann DermatolVenereol 2004;131:984-6.

5. Causeret AS, Skowron F, Viallard AM, Balme B,Thomas L. Subungual blue nevus. J Am AcadDermatol 2003;49:310-2.

6. Kim HS, Kim YJ, Kim JW, Yu DS. Subungual bluenevus. J Eur Acad Dermatol Venereol 2006;21:271-2.

7. Naylor EMT, Ruben BS, Robeinson-Bostom L, TelangGH, Jel l inek NJ. Subungual blue nevus withcombined phenotypic features. J Am Acad Dermatol2008;58:1021-4.

8. Lee EJ, Shin MK, Lee MH. A subungual blue naevusshowing expansile growth. Acta Derm Venereol2012;92:162-3.