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Case Presentation A 68-year old Caucasian male presented inthe clinic with an 18-month history of a‘bruised’ toe nail. A generally fit and wellretired chemical worker, he had recentlyattended the local minor injuries centrefollowing a GP referral as he wasconcerned that it had been weeping andwas becoming increasingly tender,especially when wearing shoes. At the time,the lesion was diagnosed as a haematomaand was lanced to drain the area. Thetreating nurse advised the patient to see apodiatrist. The patient was also prescribeda course of antibiotics but he reported thishad made little difference to the toe.

On examination at the podiatry clinic(see Figure 1) there was a raisedpigmented lesion on the nail bed withsevere erosion of the nail plate. The patientcould not recollect any particular traumato the area and reported that the lesionhad been steadily growing over an 18-month period.

In view of the unusual and suspiciousappearance, along with the history, thepatient was immediately referred to thelocal dermatology department. Within afortnight, following an assessment of thepatient, a biopsy was taken from the areaand a diagnosis of malignant melanomawas made with a reported Breslowthickness of 8mm.

Subsequently, the hallux was amputatedand as tests had revealed swelling of aninguinal lymph node, which suggestedmetastatic spread of the lesion, surgicalremoval of the inguinal lymph nodes wasundertaken. A subsequent CT scan wasperformed of the head and torso, whichwere clear. The patient’s treatment planwas a 3-monthly check and 6-monthly CT

scans. No further treatment was deemednecessary at this stage.

Discussion Melanoma of the nail is a rare tumourmost frequently affecting the hallux andthumb.1 Evidence suggests it onlyrepresents around 0.7-3.5% of allmelanoma,2,3 although this rate is muchhigher in non-Caucasian populations suchas African4 and Oriental,5,6 reflecting thelower proportion of melanoma elsewherein more pigmented skin types.

Nail melanoma most frequently affectsthe hallux and thumb nail unit, presumablyas Banfield7 suggests because these twoareas hold the largest proportion of nailmatrix tissue. Considering the relativelysmall surface area of the nail matrices (wellbelow 1% of total body surface area), nailmelanoma probably occurs more frequentlythan would be expected.8 The reasons forthis are unclear. The aetiology of nail andother acral melanoma is unlike cutaneousmelanoma elsewhere. One study

investigated the risk factors: although totalbody sun exposure was shown to be a riskfactor, there was no clear cause.9 Otherfactors suggested included occupationalexposure to chemicals (such as farmers,chemical industry workers,photographers)9,10 and having a highercount of plantar and palmar naevi.11

The higher than expected prevalence ofnail unit lesions could conceivably be putdown to trauma, but this is debatable basedon current evidence. In a case control studyof 156 patients with cutaneous melanoma,patients showed an elevated, butstatistically insignificant, risk of developingmelanoma after trauma to pre-existinglesions.12 Morhle & Hafner,13 in a study of406 cases of specifically nail melanoma,identified a high proportion of hallux andthumb lesions and demonstrated manypatients who reported trauma related tothe onset of their lesions. However, theysuggested that this could be coincidence.

Work by Briggs14 suggested thatcoincidental trauma may simply draw thepatient’s attention to a pre-existingmelanoma. Kaskel et al 15 in a survey ofover 300 patients showed that over 90%did not believe that trauma played a partin the development of their lesions andhighlighted that acral areas of the bodysuch as the hands, feet and nails werenaturally more prone to physical traumaanyway. Fanti et al 16 concluded trauma notto be a risk factor in their cohort of 1170melanoma patients (including 34 with nailmelanoma).

The presentation of melanoma of thenail unit has been well described byBristow et al 17 in their foot melanomaguidelines. There are two main patterns ofnail unit melanoma - longitudinal

Case Study. A late diagnosis of nail melanomaarising in the halluxIvan Bristow PhD, Faculty of Health Sciences, University of Southampton*& Andrea Dalton BSc (Hons), ACD Podiatry Ltd, Hemel Hampstead

*Corresponding author: ib@soton.ac.uk

Subungual or nail melanoma is a rare form of the disease,accounting for only 3.5% of all cases of melanoma. The authorspresent a case that highlights the common issue of delayeddiagnosis contributing to a poor prognosis for the condition

Figure 1. Raised pigmented lesion on the nailbed with severe erosion of the nail plate.

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melanonychia and amelanotic tumours.The development of a solitary longitudinalmelanonychial streak, arising from the nailmatrix in a white, older adult should beconsidered suspicious, particularly wherethere is progressive widening of the streakand blurring of its borders. Amelanoticmelanoma of the nail unit presents more ofa diagnostic challenge, as lack of pigmentin a developing lesion can lower levels ofsuspicion for the patient and practitioneralike. Essentially, any change to a singlenail, or its peri-ungual structures that failsto resolve or respond to treatment shouldbe considered for prompt referral.Successful management of the problem

can only be achieved if the patient consultsearly. Late presentation of melanoma,particularly in the nail and acral locations,is a common17,18 but serious problemleading to delay and a poorer prognosis, asthe patient presents with more advanceddisease. Commonly cited reasons for delayin presenting melanoma to a healthcareprofessional include gradual of ‘quiet’appearance of the lesion, lack of systemicsigns, absence of awareness of the urgency,occupational reasons and absence of

pain.19 In addition, as this case illustrates,misdiagnosis by healthcare professionals isanother delaying factor. Securing adiagnosis relies on a vigilant healthcareprofessional with a level of awareness ofthese lesions. A study of physicians in thediagnosis of melanoma demonstrated thatacral and nail lesions were frequentlymisdiagnosed.20

ManagementA diagnosis is made after biopsy, histologyand specialist interpretation. The onlyeffective treatment for the condition iscomplete excision of the lesion beforemetastases occur, although, for the reasonsgiven above, lesions may present late. The

Breslow thickness is a standardmeasurement used in histology and givesan indication of the prognosis in patientswith confirmed melanoma.21 The Breslowthickness is a measure (in millimetres) ofthe vertical depth of the tumour measuredfrom the top layer downward to the lowesttumour cells. Lesions that have a greaterthickness are closer to the lymphaticvessels and capillaries and are thereforemore likely to metastasise. The five-yearsurvival rates predicted by the Breslowthickness are as shown in Table 1.22

The prognosis maybe adversely affectedif regional and distant metastases develop.Typically with melanoma these tend tooccur in the surrounding skin, bone andthe brain. In most cases of nail melanoma,an amputation of part or the whole of theaffected digit is the surgical choice withregular monitoring of the patient, as acrallesions tend to have more poorly definedmargins making clear excision moredifficult.23

The role of the podiatrist in detectinglesions early is the key. In addition,educating the public and other healthcareprofessionals to raise awareness of

Thickness at excision Probability of5 year survival

<1mm >95%1-2mm 90%2-4mm 63-67%%>4mm 45%

Table 1. Five-year survival rates predictedby the Breslow thickness

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melanoma should be a priority, emphasisingthat it can occur anywhere on the skin –including on the foot or in the nail.

Suggested Reading1. Bristow IR, de Berker DA, Acland KM, Turner

RJ, Bowling J: Clinical guidelines for therecognition of melanoma of the foot and nailunit. J Foot Ankle Res 2010; 3.

References1. Arican O, Sasmaz S, Coban YK, Ciralik H:Subungual amelanotic malignant melanoma.Saudi Medical Journal 2006, 27(2): 247-249.

2. Krige JE, Isaacs S, Hudson DA, King HS, StroverRM, Johnson CA: Delay in the diagnosis ofcutaneous malignant melanoma. A prospectivestudy in 250 patients. Cancer 1991, 68(9): 2064-2068.

3. Levit EK, Kagen MH, Scher RK, Grossman M,Altman E: The ABC rule for clinical detection ofsubungual melanoma. J Am Acad Dermatol 2000,42(2, Part 1): 269-274.

4. Bellows CF, Belafsky P, Fortgang IS, Beech DJ:Melanoma in African-Americans: Trends inbiological behavior and clinical characteristics overtwo decades. J Surg Oncol 2001, 78(1): 10-16.

5. Chang JW, Yeh KY, Wang CH, Yang TS, Chiang HF,et al: Malignant melanoma in Taiwan: aprognostic study of 181 cases. Melanoma Res2004, 14(6): 537-541.

6. Roh MR, Kim J, Chung KY: Treatment and

outcomes of melanoma in acral location in Koreanpatients. Yonsei Med J 2010, 51(4): 562-568.

7. Banfield C, Dawber R: Nail melanoma: a reviewof the literature with recommendations toimprove patient management. Br J Dermatol1999, 141(4): 628-632.

8. Haneke E: Ungual melanoma – controversies indiagnosis and treatment. Dermatologic Therapy2012, 25(6): 510-524.

9. Green A, McCredie M, MacKie R, Giles G, YoungP, et al: A case-control study of melanomas of thesoles and palms (Australia and Scotland). CancerCauses Control 1999, 10(1): 21-25.

10. Fortes C, Vries Ed: Nonsolar occupational riskfactors for cutaneous melanoma. Int J Dermatol2008, 47(4):319-328.

11. MacKie RM: Incidence, risk factors andprevention of melanoma. Eur J Cancer 1998,34(Supplement 3):3-6.

12. Troyanova P: The role of trauma in themelanoma formation. Journal of BUON : officialjournal of the Balkan Union of Oncology 2002,7(4):347-350.

13. Mohrle M, Hafner HM: Is subungual melanomarelated to trauma? Dermatology 2002,204(4):259-261.

14. Briggs JC: The role of trauma in the aetiology ofmalignant melanoma: a review article. Br J PlastSurg 1984, 37(4):514-516.

15. Kaskel P, Kind P, Sander S, Peter RU, Krahn G:Trauma and melanoma formation: a trueassociation? Br J Dermatol 2000, 143(4):749-753.

16. Fanti PA, Dika E, Misciali C, Vaccari S, Barisani

A, et al: Nail apparatus melanoma: Is trauma acoincidence? Is this peculiar tumor a real acralmelanoma? Cutaneous and Ocular Toxicology2013, 32(2):150-153.

17. Bristow IR, de Berker DA, Acland KM, Turner RJ,Bowling J: Clinical guidelines for the recognitionof melanoma of the foot and nail unit. J FootAnkle Res 2010, 3(25).

18. Bennett DR, Wasson D, MacArthur JD, McMillenMA: The effect of misdiagnosis and delay indiagnosis on clinical outcome in melanomas ofthe foot. J Am Coll Surg 1994, 179(3):279-284.

19. Richard MA, Grob JJ, Avril MF, Delaunay M,Gouvernet J, et al: Delays in diagnosis andmelanoma prognosis (I): the role of patients. IntJ Cancer 2000, 89(3):271-279.

20. Richard MA, Grob JJ, Avril MF, Delaunay M,Gouvernet J, et al: Delays in diagnosis andmelanoma prognosis (II): The role of doctors.Int J Cancer 2000, 89(3):280-285.

21. Breslow A: Prognostic factors in the treatment ofcutaneous melanoma. J Cutan Pathol 1979,6(3):208-212.

22. Balch CM, Buzaid AC, Soong S-J, Atkins MB,Cascinelli N, et al: Final version of the AmericanJoint Committee on Cancer Staging System forCutaneous Melanoma. J Clin Oncol 2001,19(16):3635-3648.

23. Garbe C, Peris K, Hauschild A, Saiag P,Middleton M, et al: Diagnosis and treatment ofmelanoma: European consensus-basedinterdisciplinary guideline. Eur J Cancer 2010,46(2): 270-283.

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