Dermatopathology Kimiko Suzue, MD PhD October 25 and 27, 2011
Dermis Papillary dermis - the thin upper layer - of the dermis - lies directly below and interdigitates with the epidermal rete ridges. The papillary dermis is composed of loosely interwoven collagen (Collagen III) Thicker reticular dermis with its coarser and horizontally running bundles of collagen (Collagen I)
Verruca vulgaris Verrucous/papillomatous epidermal hyperplasia Hyperkeratosis Prominent keratohyaline granules Koilocytes
Verruca vulgaris
Verruca plantaris (plantar wart) Point out black dots in these warts, ie thrombosed capillaries
Verruca vulgaris (common warts)
Seborrheic Keratosis Small keratin-filled cysts (horn cysts) Down-growth of keratin into main tumor mass (pseudo-horn cysts) Benign proliferation of basaloid keratinocytes
Actinic Keratosis Solar elastosis Parakeratosis (arrow) Atypia (dermis looks purplish/sun damgae) Parakeratosis (arrow) Atypia (nuclei in bottom portion of epidermis are hyperchromatic/enlarged) Inflammation Not full-thickness atypia
Actinic Keratosis
SCC in situ - Histopathology Highly atypical cells at all levels of the epidermis Abundant mitoses, crowding of nuclei, pleomorphism, ± necrosis Cells keratinize and stain for keratin Bowen disease
Invasive SCC Endophytic growth of atypical epithelium with patchy lymphocytic infiltrate Cells have broken through basement membrane Haphazardly oriented lobules of varying shapes & sizes within the dermis Squamous pearls: whorled aggregates of parakeratotic horn Mild to severe cytologic atypia
Basal Cell Carcinoma - Histopathology Nodular masses or cords of darkly staining cells with high nucleus to cytoplasm ratio In 90% of cases, a connection to the epidermis can be seen
Basal Cell Carcinoma
Malignant Melanoma CLINICAL FEATURES: A B C D E Asymmetry Border irregularity Color variegation Diameter > 0.6 cm Evolution
Superficial spreading melanoma
Superficial spreading melanoma
Acral Lentiginous Melanoma
Malignant Melanoma HISTOPATHOLOGY: Asymmetry Architectural disorder Single-cell proliferation, not just nests Pagetoid spread: melanocytes above basal layer Cytologic atypia, usually severe
Malignant melanoma
Tumor Thickness as Sole Predictor of Outcome 10 years after Definitive Therapy of Primary Melanoma Breslow Thickness (mm) Survival (%) ≤1 83–88 1.01–2 64–79 2.01–4 51–64 >4 32–54
Psoriasis
Psoriasis-Morphology Acanthosis- marked epidermal thickening Overlying parakeratotic scale Auspitz sign-Vessels in dermal papillae bleed eaily when scale is removed Munro microabscess-neutrophil microabscess in parakeratotic stratum corneum
Psoriasis
Psoriasis