Uncommon Presentations of Common Skin Cancers

Introduction

Skin cancer is one of the most common types of cancer in the world, and it has been increasing in recent years. Skin cancer usually looks like changes in moles or lesions, but sometimes it looks different. Unusual symptoms can be hard to diagnose, making them harder to treat and leading to worse results. Doctors need to understand the different ways skin cancer can show up to find it early and take care of it. This article talks about different ways skin cancers can look that people do not commonly see.

What Are the Commonly Occurring Skin Cancers?

The commonly occurring skin cancers include

• Basal Cell Carcinoma: It is the most common type of non-melanoma skin cancer, making up about 80 percent of cases. It usually comes from the basal skin cells and often looks like a shiny bump with red lines or a sore that would not heal.

• Squamous Cell Carcinoma: This cancer comes from the top skin cells and makes up about 20 percent of skin cancers that are not melanoma. It usually looks like a dry, rough bump or sore, often on parts of the skin that get a lot of sun.

• Melanoma: It comes from pigment-making cells called melanocytes. It is not as common as other skin cancers but is more dangerous. Melanoma can look like a new mole or a change in an old mole's size, shape, or color. It can happen anywhere on the body, even in places that do not get much sun.

What Are the Uncommon Presentations of Basal Cell Carcinoma?

Basal cell carcinoma (BCC) often appears as a small, shiny bump or pink growth on the skin, with a tendency to bleed easily and not heal completely.

The rare presentations of basal cell carcinoma include

• Erosive or Ulcerating Lesions - BCC normally presents as a pearly or waxy nodule with telangiectasias or a non-healing sore. However, some cases may manifest as erosive or ulcerative lesions resembling chronic wounds or infections. Two types include
  • Ulcus Rodens: Painless, large papulonodular lesion with central ulceration and rolled border, prone to spontaneous bleeding.
  • Ulcus Terebrans: Shows vertically oriented spread, causing significant destruction of skin, cartilage, and bone, potentially leading to life-threatening complications like meningitis or massive bleeding.
• Pigmented Variants - Resembles nodular variant but has brownish pigmentation, characterized by blue-purple dermal nodules due to necrosis and degeneration.
• Superficial Variant - This is the least aggressive form, presenting as multiple flat, circumscribed, erythematous plaques with slightly raised margins. It may be typically found on the trunk and extremities.
• Sclerosing or Morphoeic Variant - This is the least common variant. It appears firm, flat to slightly raised, pale-white to yellow, resembling scar tissue, commonly localized on the face.
• Fibroepithelioma of Pinkus - A rare variation manifests as singular or multiple distinct red plaques accompanied by adherent scaling and flesh-colored nodules. This is found on the trunk, inguinal, and leg or thigh areas.

What Are the Uncommon Presentations of Squamous Cell Carcinoma?

Squamous cell carcinoma (SCC) commonly presents as a firm, red nodule or flat lesion with a scaly, crusted surface, often found on sun-exposed areas like the face and hands.

Uncommon presentations or variants of squamous cell carcinoma include

• Keratoacanthoma-Like Lesions - Some SCCs may exhibit rapid growth and central keratin-filled craters resembling keratoacanthomas. While keratoacanthomas are typically benign, distinguishing aggressive SCCs from benign lesions is important.

• Verrucous Carcinoma - It is a slow-growing, exophytic tumor with a warty surface, commonly found in the oral cavity or genital region.

• Marjolin's Ulcer - Squamous cell carcinoma arising from chronic wounds, scars, or burns, often presenting as an ulcerating lesion.

• Bowenoid Papulosis - Multiple papular lesions resembling genital warts but histologically confirmed as squamous cell carcinoma in situ.

• Acantholytic Squamous Cell Carcinoma - Characterized by loss of cohesion between tumor cells, leading to acantholysis and potential aggressive behavior.

• Spindle Cell SCC - Composed of spindle-shaped tumor cells, often occurring in sun-exposed areas and showing potential for aggressive behavior and metastasis.

• SCCs in Uncommon Sites - Oral papillary squamous cell carcinoma is a rare variant of SCC that presents in the palate, deviating from the more common sites of occurrence for SCC. Similarly, cutaneous squamous cell carcinomas in sun-protected areas are uncommon, but there have been reported cases of lesions appearing in unusual sites, such as the perianal region, fingers, back, and abdominal wall.

What Are the Uncommon Presentations of Melanoma?

Melanoma usually presents as an asymmetric, irregularly bordered, multicolored lesion with a diameter larger than 6 mm, often evolving or changing in size, shape, or color.

The uncommon variants of melanoma include:

• Desmoplastic Melanoma - This accounts for less than 4 percent of melanomas. It primarily affects older men on sun-exposed skin, often appearing as non-pigmented nodules or plaques. Diagnosis can be delayed due to its resemblance to benign conditions.

• Polypoid Melanoma - This is a variant of nodular melanoma that presents as elevated lesions with frequent ulceration, commonly mistaken for benign growths. It has a poor prognosis due to deep penetration and rapid metastasis.

• Primary Dermal Melanoma - A rare subtype confined to the dermis with distinct histologic features. It appears as nodular or plaque-like lesions on the extremities.

• Verrucous Malignant Melanoma - This resembles benign lesions and can occur de novo or from other melanoma types. It resembles benign lesions, such as verrucous nevi or seborrheic keratosis.

• Pigmented Epithelioid Melanocytoma - It is found on the extremities and is characterized by its nodular or plaque-like appearance and blue-black coloration.

• Mucosal Melanoma - This rare variant is challenging to diagnose early and has a poor prognosis. It occurs in mucous membranes, such as the oral or nasal cavity.

• Nevoid Melanoma - It mimics benign nevi but behaves aggressively. It can be present in various forms, like black or brown nodules, plaques, or papules.

• Amelanotic Melanoma - It is often misdiagnosed due to its lack of pigmentation and poses challenges in diagnosis and treatment. It resembles benign lesions or dermatitis and is commonly located on the trunk, head, neck, and lower limbs.

• Follicular Melanoma - It originates in hair follicles and is rare. It is difficult to diagnose due to its subtle clinical presentation. It resents pigmented macules, pigmented cystic lesions, or pseudocomedones. It is characteristically smaller than 0.5 cm in diameter.

Conclusion

Unusual signs of common skin cancers show how important it is for dermatologists to monitor patients and carefully check for abnormalities. Identifying these unusual signs requires a strong sense of suspicion and knowing how people can show symptoms. Ongoing learning and knowing about different ways skin cancers can look is very important for diagnosing them correctly and giving patients the best care.