CASE #1: Bowen's disease
Full-thickness epidermal atypia on biopsy led to a diagnosis of Bowen's disease, or squamous cell carcinoma in situ. In 66% of cases, Bowen's manifests as a solitary, asymptomatic, slowly enlarging, erythematous patch or plaque. The hyperkeratotic, crusted, fissured, or ulcerated lesion ranges in size from 3 mm to 3 cm and is usually scaly. Scale removal exposes a dull surface that can be papillated or moist. An occasional lesion may be topped by crusted serum. Colors include red, pink, yellow, off-white, gray, or any combination of these. Brown lesions, primarily in the anogenital area, resemble melanoma. The typically irregular lesion border is sharply demarcated.
Bowen's disease occurs most often in elderly men, usually on the head and neck and then the limbs. Penile lesions feature a glistening erosion called “erythroplasia of Queyrat.” Vulval lesions are white patches called “leukoplakia.”
Causes include exposure to arsenic and UV or ionizing radiation. Bowen's is also seen in patients with human papillomavirus (HPV-16 being the most common) and in those with immune systems suppressed by such drugs as cyclosporine or azathioprine.
Bowen's resembles a variety of inflammatory processes, including abrasion, actinic keratosis, allergic contact dermatitis, basal cell carcinoma, eczematous dermatitis, lichen planuslike lichenoid keratosis, lichen simplex chronicus, irritant contact dermatitis, melanoma (in the anogenital areas), nummular dermatitis, Paget's disease (mammary and extramammary), psoriasis, seborrheic keratosis, squamous cell carcinoma, stucco keratosis, and verucca vulgaris. The most telling feature of Bowen's is the presence of crusted serum along with scale.
Shave biopsy revealing full-thickness atypical keratinocytes (some large and pale with abundant ground-glass cytoplasm, so-called pagetoid keratinocytes) is diagnostic. Vacuolization, mitoses, individually keratinizing cells, and multinucleated cellsare also seen. Hyperkeratosis, parakeratosis, and acanthosis are sometimes observed, and an inflammatory cell infiltrate (most often lymphocytic) may be present.
Topical treatments include 5-fluorouracil and imiquimod 5% cream. More serious cases may be treated by cryotherapy, electrodesiccation and curettage, photodynamic therapy, x-ray or grenz-ray radiation, or carbon dioxide laser ablation. Surgery, usually reserved for lesions on the face, hands, or feet, includes simple excision with conventional margins and Mohs micrographic surgery. Mohs surgery and x-ray have the highest cure rates, but they are the most expensive and should be reserved for areas needing a tissue-sparing approach. The morbidity and mortality of Bowen's disease are low, so topical or destructive therapies can be tried initially. Local recurrence occurs via extension of atypical keratinocytes down the follicle.
Eight weeks of cryotherapy and topical imiquimod 5% cream every other day left the cancer visually undetectable.