Melanosis of the vulva: A long-term follow-up from Brisbane, Australia

doi:10.4236/ojog.2012.23051

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Open Journal of Obstetrics and Gynecology, 2012, 2, 247-249 OJOG

http://dx.doi.org/10.4236/ojog.2012.23051 Published Online September 2012 (http://www.SciRP.org/journal/ojog/)

Melanosis of the vulva: A long-term follow-up from

Brisbane, Australia

Ian S. C. Jones

Women’s and Newborn Services, Royal Brisbane and Women’s Hospital, Brisbane and University of Queensland, Herston, Australia

Email: [email protected]

Received 14 May 2012; revised 21 June 2012; accepted 4 July 2012

ABSTRACT

Object: To determine if vulvar melanosis progressed

to melanoma over a period of 20 years or more.

Methods: In 2010 the hospital records from the Royal

Brisbane Hospital Vulvar Clinic between 1976 and

1988 were reviewed and cross checked with the state

wide Queensland Centre for Gynaecological Cancer

(QCGC) data base to determine if any patient had

been lost to follow up and subsequently developed a

vu lvar melanoma. Data collected were stored and ana -

lysed using the computer software Statistical Package

for the Social Sciences (SPSS) 11.0. Results: None of

the 12 patients developed vulval melanoma in the

years up to 2010. Conclusion: In this small group,

followed for more than 20 years, melanosis was not a

precursor of melanoma. One patient, who attended

the Vulvar Clinic but was not included in this mela-

nosis study, was found to have co-existing melanosis

well away from her melanoma in situ and malignant

melanoma at presentation. It was not possible to de-

termine if these findings represented a progression of

the benign to malignant. Biopsy of abnormal hyper

pigmented vulvar skin is recommended. Current know-

ledge suggests that vulvar melanosis is a benign con-

dition but to be on the safe side follow up of all hyper

pigmented vulval lesions to detect early malignant

change is recommended.

Keywords: Vulva; Pigmented Epithelial Disorders;

Features; Follow-Up; Malignancy

1. INTRODUCTION

Variations in melanin pigmentation of the vulval skin are

considerable within and between different races, age and

in relation to hormonal status [1]. Causes of hyperpig-

mentation due to melanin excess include lentigo; melanin

incontinence with melanin within macrophages in the

upper dermis following inflammation; adult vulval acan-

thosis nigricans which affects the entire vulva; pseudo-

acanthosis nigricans of flexural skin in obese and darkish

skinned people and following fixed drug eruption. The

main concern is distinguishing between benign lesions

and malignant melanomas of the vulva. Vulval skin bi-

opsy will distinguish between areas of hyperpigmenta-

tion due to melanin, melanoma in situ and malignant

melanomas. The macroscopic and histological features of

normal vulval skin during life have been described else-

where [2].

The aim of this paper is to review the clinical features,

look for predisposing factors and determine the long

term outcomes for women who presented to the Vulval

Disease Clinic at the Royal Brisbane Hospital between

1976 and 1988 with vulvar melanosis and determine if

any lesion progressed to a melanoma.

2. METHODS

All patients presenting to the Vulval Diseases Clinic be-

tween 1976 and 1988 had their clinical and pathology

details recorded on proforma cards in addition to the

hospital records. In 2010 the hospital records were re-

viewed and the proforma cards up dated. Records were

cross checked with the state wide Queensland Centre for

Gynaecological Cancer (QCGC) data base to determine

if any patient had been lost to follow up and subse-

quently developed a gynaecological malignancy, espe-

cially vulval malignant melanoma.

Data from the up-dated proforma cards were stored

and analysed using the computer software Statistical

Package for the Social Sciences (SPSS) 11.0.

Ethics approval for the review of case records was ob-

tained from the Clinical Research Ethics Committee of

the Royal Brisbane and Women’s Ho spital.

3. RESULTS

Of 361 patients seen at the clinic between 1976 and 1988,

12 (all Caucasian) were found to have vulvar melanosis.

Patient age at presentation is shown in Tabl e 1, with the

majority being aged 50 or more. The three patients under

50 years of age were all menstruating regularly. All but

OPEN ACCESS

I. S. C. Jones / Open Journal of Obstetrics and Gynecology 2 (2012) 247-249

248

Table 1. Age at time of diagnosis.

Age range Melanosis

n = 12 Melanoma

n = 42

20 - 29 0 1

30 - 39 1 0

40 - 49 3 8

50 - 59 2 7

60 - 69 3 6

70 - 79 1 11

80 - 89 2 8

90 - 99 0 1

one patient were parous. Three patients presented with a

symptomatic vulv ar dystrophy (histo ry of pruritus vu lvae

for between 3 months and 5 years), one patient presented

with pruritus vulvae du e to vulval intra epithelial n eopla-

sia (VIN 3) remote from her vulvar melanosis, and one

presented with a vaginal discharge. The other patients

were referred for review of their vulval pigmentation

noted at routine gynaecological examination. The highest

incidence of melanosis was found in post menopausal

patients (67%), but can o c cur before this time.

The anatomical location of the vulvar melanosis ap-

peared to “favour” the labia minora (8 cases) and introi-

tus (2 cases). The lesions were of variable size (1 - 5 cm),

flat and the affected skin had a normal texture. No pa-

tients had clinical groin lymphadenopathy. In an attempt

to determine if there were any predisposing features for

the development of vulvar melanosis coexisting medical

conditions were sought. Various conditions were found in

11 patients (Table 2), but apart from the possibility of

skin irritation associated with the presence of a vulvar

dystrophy being a cause rather than an association, no

predisposing features were found.

No treatments were used to manage the vulvar mela-

nosis and no patients developed malignant melanoma of

the vulva between 25 and 33 years after presenting to the

Vulval Diseases Clinic. However, another patient aged

75 who attended the Vulvar Clinic but not included in

this melanosis study, was found to have co-existing

melanosis well away from her melanoma in situ and ma-

lignant melanoma at presentation in 1977.

QCGC data from the beginning of data collection in

1985 to 2009 record 42 patients with vulval melanoma of

whom 20 died of their disease and 6 died of unrelated

causes. Their ages at diagnosis ranged from 25 to 92

years and this data was compared with the ages of diagno-

sis for the melanosis cases (Tab le 1 ). Treatment regimes

for the melanoma group included wide local excision;

partial vulvectomy; radical vulvectomy and bilateral

Ta b le 2 . Other medical disorders associated with non-neoplas-

tic epithelial disorders.

Patient identifierOther medical conditions prese nt

1 Liver disease, HBP

2 Vulvar lichen sclerosus, non-Hodgkins

lymphoma, endometrial carcin oma stage 3B

3 Micro-invasive cervical carcinoma

4 Diabetes, renal calculi, VIN 3

5 Vulvar lichen sclerosus, pernicious anaemia,

depression

6 Mixed vulvar dystrophy, CVA, depression

7 BCC nose, r enal calculi, HBP

8 Cervical carcinoma with radiotherapy treatment

9 Gout, brother with melanoma

10 Nil recorded

11 BCC scalp, scleroderma, anxiety

12 BCC ear

groin dissection; radical vulvectomy, vaginectomy and

groin dissection; pelvic lymphadenectomy and surgery

plus radiation therapy.

4. DISCUSSION

The aims of this paper were to determine if vulvar me-

lanosis progressed to melanoma over a period of 20 years

or more; review the clinical features; determine if there

were any predisposing features for the development of

melanoma and determine the long term outcomes for

women who presented to the Vulvar Disease Clinic with

vulvar melanosis. The need for a long term follow-up

study of melanosis was because it is unknown if melano-

sis could be a forerunner of melanoma, and if it was how

long such changes take to occur. Ta b l e 1 shows the age

distribution for p atients presenting with vulval melanosis

(36 to 85 years) compared with vulval melanoma (25 to

92 years), which because of advanced age when discov-

ered suggests some patients take a considerable time for

a melanoma to develop. Even with a 30 year follow up

this may not be long enough for some patients to develop

vulvar melanoma.

The prevalence of vulval melan osis is unknown. Large

melanotic lesions of the vulva are uncommon [3,4]. A

study of 301 new patients presenting to a gynaecology

practice over a one year period found 31 (10%) had pig-

mented lesions on the vulva, six (2%) had diffuse hyper

pigmentation of the vulva and seven (2%) had vulval

nevocytic nevi [5].

The most common cause of vulval hyperpigmentation

due to melanin (which must be distinguished histolo-

I. S. C. Jones / Open Journal of Obstetrics and Gynecology 2 (2012) 247-249

249

gically from haemosiderin), is lentigo [1]. Lentigo, also

known as lentigo simplex, is a benign pigmented prolix-

feration of epidermal or mucous membrane melanocytes

which form smooth, non-infiltrating dark brown lesions

on the labia minora and introitus. Lentigo is of unknown

aetiology and pathogenesis and lesions do not usually

exceed one cm in diameter [1]. However, in the current

study melanosis varied in size from one to five cm.

Sison-Torre & Ackerman [6] described eight women

with extensive pigmentation of the vulva and used the

term melanosis of the vulva. Th ey show ed on b iopsy that

these lesions were benign and analogous to lentigo. Len-

tigines may resemble junctional naev i, but do not exhibit

cytological atypia [7]. This raises the question could

vulvar melanosis be the big sister to lentigo simplex with

the difference being size alone?

OPEN ACCESS

Vulval pigmentation depends on the presence of cells

containing melanin [8]. The detection of such pigmen-

tation can be obscured by dermal vascularity, the thick-

ness of overlying skin and the position of the melanin

containing cells within the skin. The distribution of pig-

mentation of dark-skinned races is concentrated in the

basal layer, but varies considerably in amount. Micro-

scopic patches of melanin pigment were found in almost

80 per cent of 35 Caucasian women at post mortem when

there was no evidence of macroscopic hyper pigmenta-

tion [8].

The differential diagnosis of vulval hyperpigmentation

is lentigo; junction al naevi; following inflammatory con-

ditions like lichen planus; adult vulval acanthosis nigri-

cans which affect the entire vulva and may be associated

with an adenocarcinoma or occasionally lymphoma or

epithelial carcinoma; the pseudo-acanthosis nigricans of

flexural skin in obese and darkish skinned people (now

thought to be related to insulin resistance) and following

fixed drug eruption from for example, sulphonamides.

The most important risk for these patients is the possibi-

lity of misdiagnosing a malignant melanoma. Making a

clinical diagnosis based on the anatomical site and skin

texture is not foolproof, hence biopsy and histological

diagnosis is recommended. Even in the case of the 75

year old woman who presented with co-existing melano-

sis, melanoma in situ and malignant melanoma, it was

not possible to determine if these findings represented a

progression from the benign to malignant. The impor-

tance of follow up of all hyper pigmented vulval lesions

to detect early malignant change is stressed.

Variations in terminology to describe benign hyper-

pigmentation due to the presence of melanin include

vulvar melanosis, idiopathic lenticular mucocutaneous

pigmentation and genital lentiginosis [1]. However vul-

var melanosis or its other name melanosis vulvae seem to

be terms used by the majority when referring to this con-

dition.

5. CONCLUSION

The difficulty in finding a suitable term for benign hy-

perpigmentation of vulval skin conditions remains. To

reliably diagnose a hyper pigmented vulval lesion a

histopathology diagnosis is required. Current knowledge

suggests that vulvar melanosis is a benign condition but

to be on the safe side follow up of all hyper pigmented

vulval lesions to detect early malignant change is re-

commended.

6. ACKNOWLEDGEMENTS

Thanks to the Queensland Centre for Gynaecological Cancer (QCGC)

staff for their assistance in providing data and checking their data on

the current study patients.

REFERENCES

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[3] Estrada, R. and Kaufman, R. (1993) Benign vulvar mela-

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doi:10.1016/0190-9622(90)70017-C

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