Deep Penetrating Nevi
DPN Showing Wedge-Shaped InfiltrateThis is a subtle case of deep penetrating nevus (DPN) on low-power examination. There are, however, dermally located subtle nests and fascicles of melanocytes . There is…
Aggressive Epidermotropic CD8(+) Cytotoxic T-Cell Lymphoma
Often disseminated tumors, nodules, and papules Rapid spread to lungs, testes, brain, and oral cavity Often treated with multiagent chemotherapy • Often spares lymph nodes • Rare compared to other cutaneous T-cell…
Actinic Keratosis
Clinical Photograph of Actinic KeratosisClinical photograph of the scalp of an elderly patient shows multiple actinic keratoses (AKs) with prominent crusting. (Courtesy J. Wu, MD.) Bowenoid Actinic KeratosisBowenoid AK shows…
Angiolipoma
Male predominance • Forearm, trunk, and upper arm most common sites • Painful tender subcutaneous nodules Often multiple • Treatment: Simple surgical excision • Excellent prognosis Local recurrence very rare No risk of malignant…
Melanoma, Nodular Type
Crusted Scalp TumorThe tumor is crusted on the scalp of this elderly man. The skin-colored nodule on the left is benign, either a neurofibroma or a neurotized intradermal nevus. (Courtesy…
Intravascular Large B-Cell Lymphoma
Most frequent in females, usually younger patients Better prognosis (3-year survival rate of 56%, systemic variant: 22%) Microscopic • IVLBCL cells are large, with vesicular nuclear chromatin, distinct nucleoli, and frequent…
Syringocystadenoma Papilliferum
Rare cases may transform to syringocystadenocarcinoma papilliferum Rarely, basal cell carcinoma may develop within SCP Microscopic • Endophytic/exophytic adnexal tumors Invaginations that communicate with epidermal surface Invaginations have papillary architecture • Papillary…
Congenital Melanocytic Nevi
< 1.5 cm = small > 1.5 cm to < 20 cm = medium > 20 cm = large • Risks, particularly for large congenital melanocytic nevus ~ 5% risk of…
Verruca Vulgaris (and Variants)
Palmoplantar warts show especially prominent keratohyaline inclusions • Lesions may be irritated and inflamed, often associated with reactive atypia Top Differential Diagnoses • Verrucous keratosis • Seborrheic keratosis • Lichen simplex chronicus • Hypertrophic lichen…
Pigmented Epithelioid Melanocytoma (“Animal-Type Melanoma”)
Medium-sized epithelioid cells, large epithelioid cells, and spindled cells • Spindled blue nevus-like cells • Large epithelioid cells • Does not exhibit brisk dermal mitotic activity Ancillary Tests • Loss of expression for protein…
