While melanoma usually develops on the
skin, it occasionally occurs on other parts of the body, such as the
mouth, eye, and inside of the nose. Such melanomas are called
"hidden melanomas" because they occur in places not easily examined
or not thought necessary to examine.
Fortunately, hidden melanomas are relatively uncommon; however, they
are worth knowing about because treatment is most effective in the
early stages. Hidden melanomas tend to develop in four areas:
(underneath the nail)
Tissue (tissue lining the nose, mouth, female genitals,
urinary tract, and esophagus)
Eye (eyelid or pigmented coating of the
Since hidden melanomas are not easily
seen, most are not discovered until they are in an advanced stage.
To help you recognize hidden melanomas, the following describes
where hidden melanomas occur and possible warning signs.
Called "subungal (under a nail) melanoma" by dermatologists, this
form accounts for about 2% of melanomas in white-skinned individuals
and 30% to 40% of melanomas in non-whites. It occurs with equal
frequency in males and females, appears most often in people over 50
years of age but can develop at any age, and is seen most often
under the nail of the thumb or great (big) toe.
Signs: The most common early warning sign is the appearance
of a brown to black-colored streak underneath the nail, which is
often mistaken for a bruise. Patients often recall a recent injury
to the area, such as stubbing a toe or smashing a thumb, and believe
the discoloration is an under-the-nail bruise. For this reason, a
physician is usually not consulted. Another reason people delay
seeing a doctor is that nail streaks frequently occur in people with
Anyone who sees the following underneath a nail, regardless of race,
should be seen by a dermatologist as soon as possible:
Very wide or variegated brown streak
Nail bed is elevated or has separated
from nail bed
Skin next to the nail becomes darker
(more advanced stage)
Nail looks deformed or as if it is
being destroyed (more advanced stage)
Subungal melanoma should be suspected
whenever: 1) a nail streak appears without known injury to the nail,
2) the nail discoloration does not gradually disappear as would a
bruise, or 3) the size of the nail streak increases over time.
Diagnosis and Treatment: Biopsy (surgical removal of all or
part of the lesion) is the only way to diagnosis melanoma with 100%
certainty. In the early stages, treatment consists of surgically
removing the melanoma. More advanced melanoma may require amputation
of the affected finger or toe along with possible removal of the
regional lymph nodes and chemotherapy.
Primary melanomas can arise in mucosal tissue lining the nose,
mouth, female genitalia, anus, urinary tract, and esophagus. While
these melanomas are relatively rare, they tend to be well advanced
when diagnosed — probably because the mucosal tissues are
"out-of-sight and out-of-mind" and infrequently self-examined or
impossible to examine easily.
Nose and mouth (signs): The most common places for primary
(where cancer first occurs) mucosal melanomas to develop are the
nose and mouth. Treatment is often delayed because the early signs
and symptoms are minor and often ignored or misinterpreted. Signs
and symptoms are:
Nose - Nosebleeds and nasal stuffiness,
which may be misinterpreted as "sinus trouble"
Mouth - A pigmented mass and pain on
swallowing, which may be misinterpreted as a canker sore or sore
throat. By the time melanoma causes pain, it is probably quite
advanced; however, an annual oral examination by a physician may
detect melanoma in the mouth before it is well advanced.
Mouth/nasal cavities (nasopharyngeal) -
Inflammation of the inner ear (otitis media), which may be
misinterpreted as an ear infection.
Female genitals (signs): A very
small percentage of melanomas occur in the female genitals. When it
does occur, melanoma develops on the vulva and/or vagina. These
melanomas are usually detected during a gynecologic examination. The
most common signs and symptoms are:
When melanoma arises on the vulva, it
occurs on the labia minora, labia majora, or clitoris, and may
extend into the vagina. The most common signs and symptoms are
vaginal discharge, pain, bleeding, and itching, which may be
mistaken for vaginal infection or menstrual irregularity. Most
patients with advanced melanomas feel pain and have a recognized
change in size, shape, or color of a mole on the vulva.
Vaginal melanoma that does not begin as vulvar melanoma is very
rare. When in its early stages, vaginal melanoma does not exhibit
signs or symptoms. The common signs and symptoms of advanced disease
are vaginal bleeding, foul odor, discharge, and vaginal pain. Most
advanced lesions cause symptoms and are diagnosed during a
Anus (signs): This type of melanoma is referred to in medical
terminology as “anorectal (pertaining to both the anus and rectum)
melanoma.” Early lesions usually cause no symptoms. In advanced
cases, signs and symptoms may include:
Urinary Tract (signs): Melanoma
of the urinary tract occurs in both males and females. In the early
stages, symptoms are not present. In advanced urethral melanoma, the
signs and symptoms are:
Esophagus (signs): Melanoma that
first occurs in the esophagus is extremely rare. In the early
stages, there are no symptoms. Signs and symptoms of advanced tumors
Treatment: Surgery is the
preferred initial treatment for melanoma of the mucous membranes. In
advanced cases, a lymph node biopsy (surgical removal and
microscopic examination of one or more lymph node nearest the tumor)
and chemotherapy may be necessary.
Melanoma that develops on the scalp is considered hidden because the
lesion can be easily hidden by hair and the scalp is difficult to
self-examine. Symptoms are usually not present until the melanoma is
well advanced, so it is very important to examine the scalp during
self-examinations for signs of melanoma. Systematically parting the
hair with a blow dryer can help.
Signs and symptoms of advanced melanoma on the scalp include:
Pigmented lesion that has recently
appeared or changed
Lesion follows the ABCDs of Melanoma
Detection - Asymmetrical, border irregular, color varies, and
diameter greater than 6 millimeters. While melanomas are usually
greater than 6 millimeters (size of a pencil eraser) when diagnosed,
they can be smaller. If you notice a mole different from others, or
which changes, itches or bleeds even if it is smaller than 6
millimeters, you should see a dermatologist.
Treatment: The lesion is
surgically removed, and one or more lymph nodes in the neck may be
removed to determine the cancer’s stage. With thicker lesions, there
is a possibility of melanoma spreading to nearby lymph nodes in the
neck as well as the lungs, liver, and brain.
A well-developed brownish-black melanoma lesion on the
a 65-year old woman. The lesion was diagnosed as
superficial spreading melanoma and surgically removed.
(Photo used with
permission of the American Academy of Dermatology National
Library of Dermatologic Teaching Slides)
Melanoma can develop in the lining of the eyelid (conjunctiva) or
the thin pigmented coating within the eyeball (choroids). Signs and
Melanoma of the eye may first be spotted during an eye examination.
Due to the potential of the cancer to spread, early diagnosis and
treatment are essential. Anyone with suspected ocular melanoma
should see an ophthalmologist without delay. Discussion of diagnosis
and treatment of ocular melanoma is beyond the scope of this
Early Detection Possible
It is possible to detect a hidden melanoma in its earliest stage.
During self-examination, the "hidden" areas — fingernails and
toenails, web spaces between fingers and toes, skin folds in the
armpits, and the scalp — should be examined. For those areas that
cannot be self-examined, routine gynecologic, ophthalmologic, and
dental examinations should include examination for pigmented
Ross MI, Stern SJ. Mucosal melanomas. In: Balch CM et al (Eds).
Cutaneous Melanoma, 3rd ed.
St. Louis: Quality Medical Publishing,
content solely developed by the American Academy of Dermatology