Page 74 - The Netter Collection of Medical Illustrations - Integumentary System_ Volume 4 ( PDFDrive )

Plate 3-9 Integumentary System

MAMMARY AND EXTRAMAMMARY
PAGET’S DISEASE
Eczematous type
of Paget’s disease
Extramammary Paget’s disease is a rare malignant
tumor that typically occurs in areas with a high density
of apocrine glands. It is most commonly an isolated
finding but can also be a marker for an underlying
visceral malignancy of the gastrointestinal or genitouri-
nary tract. Paget’s disease is an intraepidermal adeno-
carcinoma confined to the breast; it is commonly
associated with an underlying breast malignancy.
Clinical Findings: Extramammary Paget’s disease
is most often found in the groin or axilla. These two
areas have the highest density of apocrine glands. It is
believed that extramammary Paget’s disease has an
apocrine origin. There is no race predilection. These
tumors most commonly occur in the fifth to seventh
decades of life. Women are more often affected than
men. The diagnosis of this tumor is often delayed
because of its eczematous appearance. It is often misdi-
agnosed as a fungal infection or a form of dermatitis.
Only after the area has not responded to therapy is the Ulcerating type
diagnosis considered and confirmed by skin biopsy. of Paget’s disease
The tumor is slow growing and is typically a red-pink
patch with a glistening surface. Itching is the most
common complaint, but patients also complain of pain,
burning, stinging, and bleeding. The area is sore to the
touch, and there are areas of pinpoint bleeding with
friction. The red, glistening surface often has small
white patches. This has been described as the “straw-
berries and cream” appearance, and it is characteristic
of extramammary Paget’s disease. As the cancer pro-
gresses, erosions develop within the tumor, and
occasionally ulcerations form. The clinical differential
diagnosis is often among Paget’s disease, an eczematous
dermatitis, inverse psoriasis, and a dermatophyte infec-
tion. A skin biopsy is required for any rash in these
regions that does not respond to therapy. Extramammary Paget’s disease.
The tumor is often a solitary finding; however, it can
be seen in conjunction with an underlying carcinoma, Glistening red plaque with super-
ficial adherent white patches
most commonly adenocarcinoma of the gastrointestinal
or genitourinary tract. Rectal adenocarcinoma has been
the most frequently reported underlying tumor. The
percentage of these tumors that are associated with an
underlying malignancy is not known but is estimated to
be low. Appropriate screening tests must be performed
to evaluate for these associations. Usually, the underly-
ing tumor is diagnosed before the extramammary
Paget’s disease or at the same time of diagnosis.
Pathogenesis: The exact mechanism of malignant
transformation is unknown. Two leading theories exist
as to the origin of the tumor. The first is that the tumor
represents an intraepidermal adenocarcinoma of apo-
crine gland origin. The second theory is that an under-
lying adenocarcinoma spreads to the skin and forms an
epidermal component that manifests as extramammary
Paget’s disease. Although most believe this tumor to be
of apocrine origin, controversy surrounds this theory, Paget cells in epidermis (arrows) Duct invasion
and the exact cell of origin is still unknown. There are
no known predisposing factors.
Histology: The histology is diagnostic of the disease; disease. Extramammary Paget’s disease is unique in that is localized to the skin has an excellent prognosis. The
however, the pathological appearance often mimics that it stains positively with carcinoembryonic antigen treatment of choice is wide local excision. The risk of
of melanoma in situ or squamous cell carcinoma. There (CEA) and also with some low-molecular-weight cyto- recurrence is high, and lifelong clinical follow-up is
are a plethora of pale-staining Paget’s cells scattered keratins. It does not stain with S100, HMB-45, or required. The prognosis for disease associated with
throughout the entire epidermis. This type of pagetoid melanin A. The staining pattern with cytokeratins 7 and an underlying adenocarcinoma is dependent on the
spread of cells is often seen in melanoma. The cells can 20 has been used with some success to predict an under- stage of the underlying tumor. Lesions associated with
be clustered together and can have the appearance of lying adenocarcinoma; however, the routine use of an underlying malignancy have a worse prognosis.
forming glandular structures. Immunohistochemical these tests is not clinically useful at this time. Metastatic disease has a poor prognosis, and various
staining is often used to differentiate melanoma and Treatment: The prognosis for extramammary Paget’s chemotherapeutic regimens have been tried with and
squamous cell carcinoma from extramammary Paget’s disease depends on the stage of the tumor. Disease that without radiotherapy.

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