HIDRADENOMA PAPILLIFERUM
Hidradenoma
papilliferum is a rare benign tumor of the genital and perianal regions. It is
most commonly located on the vulva, although extragenital locations have been
described. It has a predilection for women in the fourth and fifth decades of
life. Typically, these are small tumors a few millimeters in diameter, but some
large tumors have been described. There is no connection to the overlying
epidermis or mucosa.
Clinical Findings: Hidradenoma papilliferum is an extremely rare benign tumor located
in the dermis. It seen almost exclusively in middle-aged women. The lesions are
almost always located in the genital region. They typically manifest as
asymptomatic nodules that are discovered incidentally. There are usually no
overlying epidermal changes, and the tumor is well circumscribed, freely
movable, and firm in consistency. They do not have a connection with the
overlying epithelium. In rare instances, they can be tender or pruritic and can
bleed or ulcerate. Most of these tumors are found on routine gynecological
examination. The most common location is the labia majora. The differential
diagnosis of a solitary, firm dermal nodule in the genital region is very
broad, and a biopsy for histopathological examination is required in all cases
to make the diagnosis. It is essential for dermatologists and gynecologists to
be aware of this tumor and the common locations in which it is found.
Pathogenesis: Hidradenoma
papilliferum is a tumor that is believed to be derived from apocrine tissue.
For this reason, it is considered to be a type of apocrine adenoma.
Apocrine glands are found in higher density in the anogenital region, and that
may be one reason for the unequal cutaneous distribution of this tumor. The
tumor is benign and is closely related to another benign adnexal tumor, the
syringocystadenoma papilliferum. The latter tumor is more common on the head
and neck, with a predilection for the scalp. Histologically, these two tumors
are almost identical, with the major differentiating factor being that the
syringocystadenoma papilliferum has a connection to the overlying epidermis.
Clinically, the syringocystadenoma papilliferum usually manifest as an
ulcerated papule or plaque. Both of these tumors can develop within a nevus
sebaceus.
Histology: Hidradenoma
papilliferum is a well circumscribed dermal tumor. It almost never has any
overlying epithelial abnormalities. The syringocystadenoma papilliferum, on
other hand, has a connection with the overlying epidermis. They both commonly
arise in conjunction with a nevus sebaceus. On closer inspection, the
hidradenoma papilliferum is composed of vascular papillary projections into the
center of the tumor lobule. These projections are lined by cells with an apocrine
origin that have a columnar configuration. Apocrine secretion (decapitation
secretion) is often noted in various sections of the tumor. There is also a
thin layer of myoepithelial cells. Within the papillary projections is a
background stroma composed of many vascular spaces and lymphocytes.
Syringocystadenoma papilliferum has almost identical
central characteristics. Compared with the hidradenoma papilliferum, it has a
more dense plasma cell infiltrate and has an attachment to the overlying
epidermis, which usually manifests as an invagination of the epidermis into the
tumor lobule.
Treatment: A
complete excision is diagnostic and curative at the same time. Often, a biopsy
is performed to ascertain the diagnosis, followed by the curative complete
excision. These are rare and benign tumors. There have been reports of
malignant degeneration, but this is exceedingly rare.
