Extramammary Paget Disease

 Sometimes with true glandular formation



• Round vesicular nuclei with prominent nucleoli

• Abundant clear cytoplasm
image May contain intracytoplasmic melanin

• Absence of intercellular bridges

• Paget cells often extend to adnexal structures

• Flattened basal keratinocytes




Ancillary Tests




• Paget cells are mucin (+)
• Primary EMPD is CK7(+) and CK20(-)

• Secondary EMPD has more variable immunohistochemical profile

image Secondary EMPD associated with urothelial carcinoma is CK7 and CK20(+)

image Secondary EMPD associated with anal/rectal carcinoma is CK20(+) and CK7(-)


Top Differential Diagnoses




• Squamous cell carcinoma in situ

• Melanoma in situ

• Clear cell papulosis

• Benign mucinous metaplasia of penis

• Pagetoid dyskeratosis

• Pagetoid reticulosis

• Melanoma in situ

image
Clinical Appearance of EMPD
This case presented as a large, moist-appearing erythematous patch affecting the groin of an elderly patient.


image
Paget Cells Involving All Levels of Epidermis
Large, pale-staining neoplastic cells image extensively infiltrate all levels of the hyperplastic epidermis in another case of extramammary Paget disease (EMPD). There is a chronic inflammatory infiltrate in the upper dermis.

image
Hyperplastic Epidermis With Marked Pagetoid Spread in EMPD
The epidermis in this case shows hyperplasia with papillary features. The neoplastic cells are numerous and affect all levels of the epidermis, including the stratum corneum image. They are arranged as single units and confluent aggregates.

image
CK7 Expression in EMPD
CK7 immunohistochemical stain strongly highlights the neoplastic cells throughout the epidermis. The use of CK7 may also assist in defining the margins of the disease.


TERMINOLOGY


Abbreviations




• Extramammary Paget disease (EMPD)


Definitions




• Adenocarcinoma involving epidermis and commonly extending to epithelium of eccrine glands &/or hair follicles (adenocarcinoma in situ)

• May involve dermis in minority of cases


ETIOLOGY/PATHOGENESIS


Pathogenesis




• Uncertain in most cases
• Cases limited to epidermis are postulated to originate from intraepidermal portion of sweat glands or from intraepidermal stem cells

• Heterogeneous condition; can be classified as primary (cutaneous origin) and secondary (extracutaneous origin)

image Primary EMPD is rarely associated with underlying sweat gland carcinoma (usually apocrine)

image Secondary EMPD: Associated with internal carcinoma in 15-29% of cases

– Genital EMPD is often associated with genitourinary carcinomas and perianal EMPD is more frequently associated with gastrointestinal carcinomas

– Most frequent in perianal EMPD (underlying rectal carcinoma in 1/3 of cases)


CLINICAL ISSUES


Epidemiology




• Age
image 6th-8th decades

• Sex
image F > M


Site




• Skin regions rich in apocrine glands
image Most common sites: Vulva and perianal region

image Other sites: Scrotum, perineum, penis, axilla, umbilicus

image Exceptional sites: Eyelid (accompanying carcinoma of Moll gland), external auditory meatus (associated with ceruminous carcinoma), face, scalp, chest, abdomen, and extremities


Presentation




• Circinate or annular moist erythematous scaly patches or plaques

• Other presentations: Gray-white eczematous patches, hypopigmented or pigmented macules, ulcerated plaques/tumors

• Pruritus is frequent and may precede clinical lesion

• Bleeding, oozing, tenderness, or burning sensation can occur

• EMPD may mimic eczema

• Lesions may be multifocal


Treatment




• Complete surgical excision is treatment of choice for primary EMPD
image Patients require long-term follow-up because of multifocal nature of condition and high recurrence rate

• Treatment in secondary lesions will depend on associated carcinoma

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Apr 24, 2017 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Extramammary Paget Disease
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