Sebaceous hyperplasia

Clinical features

•This is common and presents as single or commonly multiple, yellow dome-shaped umbilicated papule(s)  (1-2 mm diameter) on face of the elderly but may occur on the chest, the caruncle, external genitalia & areola

•M>F

•Increased incidence with cyclosporine

Histological features

•Lobules drain into a dilated follicle

•Lobules are increased in number but do not differ in structures from normal sebaceous glands

•Sebaceous hyperplasia is not associated with Muir-Torre syndrome

Sebaceous adenoma

Clinical features

•Rare

•Presents as a pink/red to yellow papule/nodule most often on the face of elderly patients up to 0.5 cm diameter

•Can present on the medial canthus

•Associated with Muir-Torre syndrome

•Rare develops in a salivary gland

•May be found at the base of a keratin horn

Histological features

•Variable origin from epidermis

•Typically multilobulated, occasioanlly cystic

•Collagenous pseudocapsule

•At the periphery, single or multiple germinative cell layers maturing into typical sebaceous cells (>50%)

•Variable peripheral palisading

•+/- basal mitoses (particularly in the so-called giant variant which should not be misdiagnosed as sebaceous carcinoma)

Sebaceoma

Clinical features

•Usually single

•Flesh colored to yellow papule or nodule 1-3 cm diameter on the face or scalp

•29-87 years, most 6-9^th decade

•Associated with Muir-Torre syndrome

•May develop in nevus sebaceus & in the ocular adnexa

Histological features

•Variable continuity with epidermis

•Multinodular with surrounding collagenous stroma

•Random distribution of basaloid cells & sebocytes (<50% sebocytes)

•Duct formation, often with holocrine secretion generally present

•Mitoses sparse to conspicuous

•Absent peripheral palisading & retraction artifact

•Cystic variant

•Subtypes include rippled pattern, carcinoid-like & reticulated

. Exceptionally, sebaceous carcinoma may arise from a sebaceoma

. Exceptionally, sebaceoma has been described with a seborrheic keratosis

. CAM5.2, keratin 14, adipophilin, EMA +ve, BerEP4 negative (compare with BCC- EMA -ve, BEREP4 +ve)

Sebaceous epithelioma

This poorly deineated term was used in the older literature. It included a variety of tumors including basal cell carcinoma with sebaceous differentiation, sebaceoma & some cases of sebaceous adenoma. It should not be used.