Lumps and Bumps - Comprehensive Dermatological Guide

Warts

Common dermatological condition caused by human papillomavirus (HPV) infection.

Cutaneous HPV

Results in common warts.

Mucosal HPV

Subdivided into high-risk (e.g., HPV16, HPV18) and low-risk types. High-risk types can cause low or high-grade dysplasia, potentially leading to cancers.

Common warts (Verruca vulgaris)

Hyperkeratotic exophytic papules and nodules on fingers and dorsal hands.

Plantar warts (Verruca plantaris)

Myomesial type: Sloping sides, central depression (anthill-like), tender with lateral and direct pressure, surrounded by yellow hyperkeratotic callus-like skin with discontinued skin lines.
Mosaic type: Thick exo- and endophytic hyperkeratotic papules and plaques coalescing into a mosaic pattern, commonly seen on dorsal hands, arms, and legs.

Plane warts (Verruca plana)

Skin-colored to pink or brown papules and plaques with a smooth, flat-topped surface.

Filiform Warts

A cluster of fine fronds emerging from a narrow pedicle base, usually on the face, also described as digitate or finger-like warts.

Butcher's Warts

Caused by HPV7, affecting hands of butchers and those chronically exposed to cold, moist environments. Resemble common warts, numerous, and can appear as extensive verrucous plaques or papules on dorsal, palmar, or periungal areas of hands and fingers.

Epidermodysplasia Verruciformis

A rare autosomal recessive condition susceptible to skin infection with specific HPV types, or due to acquired immunodeficiency like HIV. Presents with widespread lesions in childhood (inherited type), with a predilection for sun-exposed sites.

Oral warts

Affect buccal, gingival, labial mucosa, tongue, and hard palate. Small, soft, mucosal, white papules and plaques. Differentials include bite fibroma, early SCC, or hick's disease.

Condylomata acuminata

Primarily affects the anogenital region, ranging from discrete lesions to large cauliflower-like lesions.

Bowenoid papillosis

Seen in the anogenital region, represented as multiple pink to red-brown verrucous papillae/plaques. In females, a pap smear is important to exclude intraepithelial neoplasia.

Erythroplasia of Queyrat

Squamous cell carcinoma in situ of glabrous skin of vulva or penis, seen as a well-demarcated red plaque that may progress to invasive SCC.

Cysts

A benign, round, worm-shaped, encapsulated lesion containing fluid or semi-fluid material.

True Cysts

Contain an epithelial lining (visible histologically and clinically).

Epidermoid cysts

Most common on the face and upper trunk, skin-colored to white-yellow papule or nodule (millimeters to centimeters). Visible comedonal-like opening or central punctum.

Milia

Small superficial epidermoid cysts (1-2 mm), white, sometimes grouped, frequently seen on the central face and periorbital region.

Pilar cysts (Trichilemmal cysts)

Most common on the scalp, sometimes with overlying alopecia. Solitary or multiple, relatively firm nodules.

Pilonidal cysts

Most common in the upper gluteal cleft, associated with a sinus tract. More common in men, and may be associated with the follicular occlusion tetrad.

Vellus Hair Cysts

1-3 mm lesions, skin-colored to brown papules, commonly on the trunk. May become inflamed.

Steatocystoma

2-10 mm skin-colored to pigmented papules/nodules, commonly on the trunk, axillae, or groin.

Hydrocystoma

Apocrine: Solitary translucent papules on the eyelid margin.
Eccrine: Solitary or multiple translucent to bluish papules on the face, becoming prominent with sweating.

False Cysts

Do not contain an epithelial lining.

Mucocele

Compressible, mucosal-colored to bluish papules/nodules, most commonly on the inner lower lip, caused by disruption of minor salivary ducts.

Digital Mucous Cysts

Skin-colored to translucent papules/nodules, most commonly on the digits, particularly the dorsal distal aspect of fingers.

Ganglion Cyst

Soft cystic nodules up to 4 mm in diameter, commonly on the wrist more than the ankle.

Pseudocyst of the Auricle

Painless unilateral swelling of the scaphoid fossa of the ear, more common in men.

Congenital Cysts

Present at birth.

Dermoid Cysts

Firm skin-colored to pink subcutaneous nodules, most often located around the eyes (especially the lateral eyebrow).

Branchial Cleft Cysts

Located on the neck along the anterior border of the sternocleidomastoid muscle.

Molluscum Contagiosum

Small round, skin-colored or pearly papules with central umbilication. Caused by the molluscum contagiosum virus (a poxvirus).

Sporotrichosis

A chronic subcutaneous mycosis caused by the fungus Sporothrix schenckii.

Erythema Nodosum

Tender erythematous nodules, commonly on the anterior shins (no ulceration or drainage). Late lesions have a bruise-like appearance.

Seborrheic Keratosis

Waxy, stuck-on, tan, brown, or black papules or plaques (stuck-on appearance).

Dermatosis papulosa nigra

Common in dark-skinned individuals, 1-5 mm hyperpigmented papules on the face.

Stucco keratosis

1-4 mm gray-white papules on the lower extremities (especially dorsal feet and ankles of older adults).

Inverted follicular keratosis

Endophytic variant of seborrheic keratosis, tan to pink papule, typically on the face of adults.