Vulva, vagina & female urethra
Melanoma
Topic Completed: 1 August 2014
Minor changes: 12 February 2020
Copyright: 2002-2016, PathologyOutlines.com, Inc.
PubMed Search: Melanoma [title] vagina
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Cite this page: Pernick N. Melanoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/vaginamelanoma.html. Accessed November 23rd, 2020.
Definition / general
Melanoma originating in vaginal wall without involvement of vulva, uterine cervix or other surrounding structures (Gynecol Obstet 3:183) Terminology
Also called primary malignant melanoma of vaginaEpidemiology
Melanomas arising from female urogenital tract occur primarily in vulva (95%) and vagina (3%)
Primary melanoma of vagina is extremely rare and aggressive
Constitutes less than 3% of vaginal cancers and only 0.3-0.8% of all melanomas in women (Gynecol Obstet 3:183)
Occurs mainly in postmenopausal women, sixth and seventh decades of life (J Chin Med Assoc 2011;74:376)
Rare cases in young patients (Int J Pathol 2009;7:102)
Diagnosis
Based on biopsy/resection specimen with clinical history and imagingRadiology description
Small tumors can be difficult to assess on CT scan
The use of fluorodeoxyglucose (FDG) as a glycolytic indicator in tumor-altered metabolism in PET/CT study can aid in early diagnosis and stagingPrognostic factors
Common sites of recurrence of vaginal melanoma are vagina, vulva, groin
Prognosis poorer than cutaneous melanomas
Five year survival rate of 13-19% is poor compared to vulvar and cutaneous melanomas
Fifty percent have positive lymph nodes, and nearly 20 percent have distant metastases at presentation
Mean survival is 8.5 months after recurrence (Gynecol Obstet 3:183)
Treatment
Many different treatment modalities have been tested, but there is no standard therapeutic approach
Surgery provides local control; procedures include wide local excision, radical surgery (total vaginectomy with or without vulvectomy), pelvic extenteration
Sentinel lymph node biopsy (SLNB) provides important prognostic and staging data with minimal morbidity
Routine lymph node dissection is not recommended because morbidity is high, and prophylactic lymphadenectomy has not been shown to improve survival (J Chin Med Assoc 2011;74:376)
It is difficult to get negative surgical margins without pelvic exenteration due to multifocality and anatomic constraints
Surgery may be combined with radiotherapy or chemotherapy
Cytotoxic chemotherapy, IFNα, IL2, ipilimumab, and vemurafenib have been used in some cases (Gynecol Obstet 3:183)
IFN is used as adjuvant therapy in patients without disease but at high risk of systemic recurrence (J Chin Med Assoc 2011;74:376)
Clinical images
Images hosted on other servers:
Diffuse black pigmentation
Colposcopic findings
Mass in posterior wall
Gross description
Can have raised, ulcerated and irregular appearance (Gynecol Obstet 3:183)
Can present as polypoid lesion or a nodule
Usually pigmented with black to brown gross appearance, but 40% cases are amelanotic Gross images
Images hosted on other servers:
Nodular mass
Microscopic (histologic) description
Diffuse infiltration of large, pleomorphic, epithelioid and spindle shaped tumor cells in vaginal mucosa
Cells have eosinophilic cytoplasm, large oval or pleomorphic hyperchromatic nuclei, may have multiple nuclei with distinct nucleoli (J Clin Pathol 2004;57:986)
Amelanotic melanomas can be difficult to diagnose on histology
Junctional activity, if present. raises suspicion for melanoma (Int J Pathol 2009;7:102)
Immunohistochemical stains are helpful if no melanin pigment or junctional activity (Gynecol Obstet 3:183)
Microscopic (histologic) images
Images hosted on PathOut server:
Contributed by Dr. Mayank Gupta, Christian Medical College, Vellore (India)
60 year old woman with nodular growth on left lateral vaginal wall
10x
20x
40x
40x
Cytokeratin (10x)
HMB45 (10x)
Melan-A (10x)
Images hosted on other servers:
Atypical tumor cells
Melanin granules
H&E, S100, HMB45
HMB45+
Cytology description
Loose aggregates of large, pleomorphic, polygonal to spindle shaped tumor cells with ill-defined cytoplasmic borders, granular hyperchromatic nuclei and conspicuous nucleoli
Multinucleated tumor cells and mitoses can be seen (J Clin Pathol 2004;57:986) Cytology images
Images hosted on PathOut server:
Loose aggregates of
pleomorphic tumor cells
Positive stains
S100, HMB45, vimentin
Melanin pigment can be demonstrated with Fontana-Masson silver staining (J Clin Pathol 2004;57:986)
MelanA, tyrosinase, MiTF Negative stains
Cytokeratin, epithelial membrane antigen (EMA), desmin, myoglobin, smooth muscle actin, CD34, CD68
Amelanotic melanomas are negative for melanin pigment (J Clin Pathol 2004;57:986) Molecular / cytogenetics description
NRAS mutations and KIT amplifications occur in both vaginal and vulvar melanomas
KIT mutations appear to be more specific for vulvar melanoma
BRAF mutations are absent in both vaginal and vulvar melanomas originating from the vulva or vagina (Mod Pathol 2014 Mar 7 [Epub ahead of print])
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