| What is squamous cell carcinoma cutaneous? | • Cutaneous squamous cell carcinoma (SCC) is an invasive malignant neoplasm of epidermal keratinocytes showing squamous phenotypic differentiation
• Bowen disease (BD) is a squamous cell carcinoma in situ (SSCIS) with full-epidermal thickness dysplasia that has the potential for significant lateral spread before invasion |
| What are major sites of squamous cell carcinoma? | • The majority (70%) of cutaneous squamous cell carcinoma (SCC) occurs on the head and neck, with an additional 15% found on the upper extremities
• Tumors of sun-protected skin are more prevalent in black persons
• These tumors carry a higher mortality risk, possibly resulting from delayed diagnosis
• Bowen disease has a similar distribution, but this condition is also seen in subungual, periungual, palmar, genital, and perianal locations. Erythroplasia of Queyrat refers to Bowen disease on the glans penis |
| How is clinical presentation of squamous cell carcinoma? | • SCC presents as a raised, firm, skin-colored or pink, often keratotic papule or plaque on a background of severely sundamaged skin, with:
• mottled pigmentary alteration
• telangiectasias
• the presence of multiple actinic keratoses
• Bowen disease presents as a slow-growing, irregular, sharply circumscribed, erythematous, velvety, or scaly plaque on sun-exposed or sun-protected skin
• Marjolin ulcers should be considered in any chronic ulcer that fails to heal or which demonstrates a changing appearance |
| What is the differential for cutaneous small cell carcinoma? | • Atypical Fibroxanthoma
• Epithelioid Angiosarcoma
• Keratoacanthoma
• Merkel Cell Carcinoma
• Metastatic Hepatic Carcinoma
• Paget Disease
• Sebaceous Carcinoma
• Spindle Cell Melanoma |
| How is histopathology of small cell carcinoma? | • full-thickness epidermal replacement by crowded keratinocytes that demonstrate disordered dyspolarity, loss of maturation, and nuclear pleomorphism with hyperchromasia
• Apoptotic or dyskeratotic cells as well as typical and atypical mitosis are present at all levels of the epidermis, as seen in the following image
• Variable loss of the granular layer with surface parakeratosis
• Involvement of hair follicles is common |
| How is immunohistochemistry for small cell carcninoma? | • The combination of HMWK (CK34βE1) and p63 positivity was found to be the strongest identifying phenotype of SCC in its multiple variants |
| How is metastasis for small cell carcinoma? | • Squamous cell carcinoma (SCC) metastases are usually discovered 1-2 years after diagnosis
• Primary tumors spread along fascial planes and nerves, as well as through lymphatics and blood vessels
• Ipsilateral regional nodes (submental, submandibular, and parotid) are the most common metastasis recipients with a rate of 80%
• Distant metastases occur in 14.8% of metastatic squamous cell carcinoma (SCC) and most commonly involve the lungs, liver, brain, skin, or bone
• Bowen disease invades the dermis in 3-4% of cases, with a higher rate of 10-14% in anogenital locations |
| How is tx of small cell carcinoma? | • Surgical excision
• Moh’s surgery
• Cryosurgery
• Chemotherapy (cisplatine)
• Radiotherapy |
