Squamous Cell Carcinoma In Situ (Bowen Disease)


Clinical Photograph of SCCis on Forearm
This is an example of squamous cell carcinoma in situ (SCCis)/Bowen disease presenting as an erythematous plaque on the forearm image of an elderly male patient who had a history of multiple skin cancers.



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SCCis (Bowen Disease)
Bowen disease (SCCis) is characterized by a proliferation of atypical intraepidermal keratinocytes filling the entire epidermis, including the granular layer image. Many of the cells show cytoplasmic clearing image.

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SCCis at High Magnification
High magnification of Bowen disease shows prominent cytologic atypia, an atypical mitotic figure image in the midepidermis, and apoptotic cells image.

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Verrucoid SCCis
Verrucoid SCCis shows hypergranulosis, mild papillomatosis, and superficial koilocytic-appearing cells, suggesting an HPV etiology. Note the scattered mitotic figures image and enlarged, bizarre-appearing, hyperchromatic-staining nuclei image.


TERMINOLOGY


Abbreviations




• Squamous cell carcinoma in situ (SCCis)


Synonyms




• Bowen disease

• Squamous intraepithelial neoplasia


Definitions




• Full-thickness intraepidermal atypia of squamous keratinocytes, often with numerous mitotic figures and apoptotic cells


ETIOLOGY/PATHOGENESIS


Sun Exposure




• Chronic UV radiation strongly implicated in SCCis


Immunosuppression




• Increased risk of developing SCCis in immunosuppressed patients, especially organ transplant recipients


HPV Infection




• Some cases of SCCis are related to HPV infection, particularly in anogenital sites
image SCCis also may arise in verrucae and condylomata


CLINICAL ISSUES


Site




• Most common on head and neck region, other sun-exposed sites


Presentation




• Scaly patch or plaque lesion

• Ulceration and hemorrhage may be present


Treatment




• Surgical approaches
image Complete surgical excision is standard and definitive therapy

image Mohs surgery often performed for facial lesions to minimize amount of tissue taken

image Electrodesiccation and curettage may also be used

• Drugs
image Topical therapy with immunomodulators, including imiquimod or 5-fluorouracil, may be used
– Patients with extensive lesions or poor surgical candidates


Prognosis




• Excellent in most cases
• Small risk for invasive squamous cell carcinoma

image Greater risk in patients with immunosuppression or numerous lesions


MACROSCOPIC


General Features




• Broad, superficial lesion with epidermal thickening and overlying scale


MICROSCOPIC


Histologic Features




• Atypical intraepidermal proliferation of squamous cells extending into upper levels of epidermis
image Basilar keratinocytes are often spared, leading to so-called eyeliner sign

• Overlying parakeratosis often diffusely present, without skip areas over adnexal structures

• Follicular epithelial involvement is typically seen

• Cells are usually markedly enlarged and atypical-appearing, with nuclear hyperchromasia and enlarged nucleoli

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Apr 24, 2017 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Squamous Cell Carcinoma In Situ (Bowen Disease)

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