Extramammary Paget’s disease (EMPD) is a rare form of skin cancer that originates in the epidermis, the outermost layer of the skin. This condition often presents as a persistent rash, making it frequently mistaken for more common, benign skin conditions such as eczema, psoriasis, or fungal infections. Its deceptive appearance can lead to delays in proper diagnosis, as patients and even some healthcare providers might initially pursue treatments for these other conditions without success. EMPD is a malignancy that develops from glandular cells in the skin.
Symptoms and Common Locations
Extramammary Paget’s disease typically manifests as a persistent, red patch on the skin, which may also appear scaly or crusted. This rash can often be accompanied by symptoms such as itching, burning sensations, or localized pain, causing considerable discomfort. In some instances, the affected skin may weep or bleed, particularly if irritated or scratched.
The most frequent sites for EMPD development are areas rich in apocrine sweat glands, including the vulva in women, and the scrotum, penis, or perianal region in men. Less commonly, it can also appear in the armpits (axillae) or on the eyelids. The rash associated with EMPD is characterized by its slow growth, often expanding gradually over months or even years. A significant indicator of EMPD is its failure to improve or resolve with standard treatments prescribed for eczema, fungal infections, or other common dermatological conditions.
Diagnosis and Association with Other Cancers
The definitive diagnosis of Extramammary Paget’s disease relies solely on a skin biopsy, where a small tissue sample from the affected area is removed and examined under a microscope. This analysis allows pathologists to identify characteristic Paget cells, which are large, clear cells with abundant cytoplasm, confirming the diagnosis.
Upon diagnosis, two forms of EMPD are distinguished. Primary EMPD originates directly in the skin and remains confined to the epidermis or underlying dermis. Secondary EMPD indicates that the skin lesion is a manifestation of an underlying internal cancer that has spread to the skin. This distinction necessitates a different management approach.
Due to the potential for secondary EMPD, a comprehensive medical evaluation is initiated following a diagnosis to screen for associated internal malignancies. This workup commonly includes imaging studies and endoscopic procedures aimed at detecting cancers in the genitourinary or gastrointestinal tracts. Examples of these screening tests include colonoscopies to examine the large intestine, cystoscopies to visualize the bladder, and computed tomography (CT) scans of the abdomen and pelvis to assess various internal organs.
Treatment Modalities for EMPD
Surgical removal stands as the primary treatment for Extramammary Paget’s disease, aiming to completely excise the cancerous cells with clear margins. Two common surgical approaches are employed to achieve this goal. Mohs micrographic surgery involves removing thin layers of skin one at a time, with each layer examined immediately under a microscope until no cancer cells are detected at the margins. This technique helps preserve healthy tissue.
An alternative surgical method is wide local excision, where the visible lesion is removed along with a surrounding margin of seemingly healthy tissue. The excised tissue is then sent to a pathology lab for examination of the margins, ensuring all cancer cells have been removed. Both surgical methods prioritize achieving clear margins to minimize the risk of recurrence.
For cases where surgery is not feasible, or for very superficial lesions, non-surgical options are considered. Topical therapies, such as imiquimod cream, may be applied directly to the skin to stimulate an immune response against the cancer cells. Radiation therapy, which uses high-energy rays to destroy cancer cells, can also be utilized, particularly for localized disease that cannot be surgically removed or to reduce symptoms. Systemic treatments like chemotherapy are reserved for rare instances where EMPD has spread beyond the local area and metastasized to distant parts of the body.
Recovery and Prognosis
The long-term outlook for individuals diagnosed with Extramammary Paget’s disease varies significantly depending on whether it is primary or secondary. For primary EMPD, where the cancer is confined to the skin, the prognosis is generally favorable following complete removal. However, a notable characteristic of primary EMPD is its high rate of local recurrence, meaning the disease can reappear in or near the original site even after successful treatment.
This tendency for local recurrence underscores the absolute necessity of ongoing, diligent monitoring. When EMPD is secondary, its prognosis is directly linked to the type and stage of the underlying internal cancer that caused the skin manifestation. In such cases, the overall outlook is determined by the aggressiveness and extent of the internal malignancy. Regardless of the type, long-term, regular follow-up appointments with a dermatologist are required to monitor for any signs of recurrence. This surveillance may also involve other specialists, such as oncologists or gastroenterologists, depending on whether an associated internal cancer was identified, ensuring comprehensive care and early detection of any new developments.