Figure 1. Vaginal melanoma: histopathological
pictures.
DISCUSSION
Melanoma is a highly metastatic, highly aggressive tumour of melanocytes
that most frequently develops in the skin but can also occur in the eyes
and mucous membranes to a much lower level. One percent of all melanomas
are mucosal, and 18 percent of them develop in the vulvovaginal areas.
Even more infrequently, between the ages of 60 and 80, just 0.46
instances per million women are diagnosed with vaginal melanoma each
year [2]. As in our instance, vaginal melanomas are typically
located in the lower portion of the anterior vaginal wall. There are no
clear identifiable causes of vaginal melanomas, and the literature does
not show any appreciable variations among racial or ethnic groups
[1]. The cellular microenvironment and interactions between any of
these have been implicated in proposed mechanisms of its pathogenesis
and etiological variables, however these hypotheses are at best [6].
Our patient’s clinical symptoms included myalgias, arthralgias,
weariness, a palpable mass in the genital area, pain, and 2 weeks’ worth
of foetid transvaginal haemorrhage. According to the bibliography,
genital bleeding (80%) and a palpable mass (15%), genital secretions
(25%), and local pain (10%) are among the symptoms of vaginal melanoma
[1,3]. Vulvar and vaginal melanomas have beginnings that are
typically missed by routine examination, with the anatomical location of
the lesion being the primary factor in the late diagnosis and poor
prognosis of these lesions. [4], Any discoloured growth in the
vagina with complaints of vaginal bleeding should be believed to be
melanoma since the growth is typically blue-black or blackish with
plaques or ulceration [3].
Most patients have advanced disease when they are first diagnosed
[1]. Vaginal melanomas are diagnosed using a combination of
histological analysis and visual inspection. When the protein S-100,
Melan A, and HMB-45 markers are positive, the diagnosis is confirmed by
pathological investigation using IHC of the biopsy sample [1].
Histologically, there are three main forms of vaginal melanomas:
epithelioid (which accounts for 55% of cases), spindled, and mixed
[2]. The big, spherical cells of the epithelioid type have a lot of
eosinophilic cytoplasm. They have peppered moth nuclei, which are
vesicular nuclei with coarse, uneven chromatin and peripheral
condensation. The most typical locations for this cell type in melanomas
are nodular and superficial spreading. The pigment is distributed
erratically, there is dermal fibrosis, and the inflammatory infiltrate
is varied (brisk, non-brisk, or nonexistent) in the stromal compartment
[4]. In order to identify the tumor’s Breslow depth, the quantity of
mitoses, the kind of ulceration, the presence of microsatellites, and
the look of the tumour margins, a thorough pathological investigation
should also be carried out [1], as described in the case of our
patient.
Prognostic variables and treatment regimens for vaginal melanoma are not
well characterised because there are not enough patients to conduct
randomised clinical studies.
The American Joint Committee on Cancer’s tumour, node, and metastases
and the International Federation of Obstetrics and Gynaecology systems
are currently used to stage primary vaginal melanoma, but the evidence
from various studies suggests that the AJCC stage, tumour size, and
lymph node status are the main prognostic factors. Poorer outcomes were
linked to AJCC stage III, tumour size 3 cm, and lymph node involvement.
In general, MM has a 10-to-20% 5-year overall survival rate compared to
93% for CM.
Additionally, the vaginal melanoma 5-year survival rate is less than
15% [5]. In appropriate circumstances, surgery is the go-to
treatment because it’s linked to a higher overall survival rate. Quality
of life and patient preferences are crucial in determining the extent of
surgery, as is the case with our patient, who refused extensive surgery.
However, the radicality of the surgery had no discernible impact on
outcomes. Routine groyne or pelvic lymphadenectomy is not advised for
individuals without signs of clinical or radiological involvement due to
the low rate of regional lymph node metastases; instead, prognosis is
the key consideration [5]. In the absence of lymph node metastases,
local excision of recurrence results in a 50% 5-year disease-free
survival rate [1]. If surgical resection is not possible, lymphatic
invasion, regional extension, or as a palliative measure, radiotherapy
may be utilised as a neoadjuvant treatment [4]. Immune checkpoint
inhibitors or targeted therapy are the preferred first-line treatments
for metastatic or incurable vaginal melanoma in the context of driver
mutations. Nivolumab and ipilimumab combination therapy or anti-PD1
monotherapy with pembrolizumab or nivolumab are the recommended starting
regimens for advanced stages (stage III-IV), respectively. This was the
treatment of choice for our patient [2,4]. Agents including
dacarbazine, iterleukin-2, and interferon alpha-2b have showed promise
in extending survival [2].
According to evidence, cytotoxic therapy mostly employs dacarbazine,
temozolomide, cisplatin, and paclitaxel as neoadjuvant or palliative
care [2,4]. It is worthwhile to investigate topical imiquimod as an
adjuvant treatment further [6]. Adjuvant chemotherapy (dacarbazine)
or the combination of targeted therapy (ipilimumab) and radiotherapy
have also been mentioned in the literature, with promising outcomes, in
addition to surgical excision.