Adnexal tumors

Group of normal vellus hairs.

Cystic tumor, lined by squamous epithelium, usually communicating with the surface. Within the wall of the cyst there are small, malformed, well differentiated follicles with hair papilla. The tumor is surrounded by fibrous tissue rich in fibroblasts.

Variant of this tumor with many sebaceous glands present as well is called sebaceous trichofolliculoma.

Groups of cysts, filled with keratin; granular layer is usually absent; epithelial strands connect the cysts; nests of keratinocytes.

Dilated open follicular cystic cavity filled with keratin with irregularly proliferating rete ridges. The lesion is sometimes pigmented.

Dilated follicular infundibulum filled with keratin, acanthotic proliferation of the follicular epithelium; cells are regular, lesion is benign.

The tumor consists of basophilic epithelium with peripheral palisading. Mitotic activity is usually minimal. The slits between tumorous nests and the stroma, but rather between the stroma and uninvolved dermis. Focal differentiation into hair bulbs with stromal reaction (and differentiation into the papilla). The tumor doesn's usually reach depper than into 2/3 of the dermis (this differs from trichoblastoma).

Large tumor (reaching at least into half of the dermis) with variable structure (many types were described).

The tumor is characterized by proliferation of basaloid cells with focal differentiation into hair follicle, especially by formation of hair papilla (epithelial and mesenchymal parts). Mitotic activity is present, but the tumor is well demarcated, stroma is in contact with the epithelium (as opposed to bazalioma).

Small nests and branching cords of squamous epithelium, small keratinous cysts, foci of keratinization, small calcifications and ossifications. Stroma is collagenous. No retraction arteracts are present.

EMA is positive (positive in microadnexal carcinoma, negative in basal cell carcinoma), stromelysin 3 is negative (positive in BCC and microadnexal carcinoma).

Nests or larger solid tumors of pale, glycogen containing epithelium; peripheral palisading, usually thick basement membrane.

Nodule consisting of dark, basophilic cells, often of high mitotic activity and pale, eosinophilic areas of keratin and necrotic cells with eosinophilic cytoplasm and lost nucleus (ghost cells).

Dystrophic calcifications and inflammatory reaction are common, sometimes ossificatinons can be found.

Intradermally located tumor, consisting of centrally located mesenchymal part (fat, blood vessels, fibrous tissue), surrounded by malformed follicles with prominent sebaceous glands.

Shallow acanthosis of pale, interconnected keratinocytes without atypia, PAS positive. The tumor is well circumscribed.

Fine collagenous bundles with some mucin and sebaceous glands in various combinations. This tumor is close to fibrofolliculoma, where epithelial part is more prominent.

Hamartomatous lesion with fibrous proliferation around hair follicle.

Groups of normal or enlarged eccrine sweat glands.

Intraepidermal tumor consisting of (usually) multiple islands of tumorous cells, which are surrounded by hyaline sheath and fit together like pieces of a jigsaw puzzle. The hyaline sheaths and hyaline droplets within the tumor are PAS positive.

The tumor consists of two kinds of cells: smaller, on the periphery of the nests (with narrower cytoplasm), and larger, more centrally located, with pale nucleus and eosinophilic cytoplasm.

The tumor can contain tiny tubules.

Intradermal tumorouus nodules, sharp circumscription, in scanning magnification may resemble lymphnodes. Bands of tumorous cells with small, dark nuclei on the periphery and larger, pale nuclei in the centre. No hyaline sheats around the bands are present. In addition tubules, PAS positive hyaline granules and scattered lymphocytes are present.

Sometimes this tumor is mixed with cylindroma. In some tumors the cells form small rosettes.

Eccrine and apocrine variants exist.

Well circumscribed tumor, consisting of one or more tumorous nodes, solid, cystic, tubular.

Solid areas contain several kinds of cells: pale (or sometimes clear) cells and dark (with eosinophilic cytoplasm), sometimes squamoid and mucinous cells are present as well. Cystic areas usually contain eosinophilic amorphous material. The lining is flat. Tubules are lined by cubic or cylindric epithelium.

Mitotic activity is present even in benign tumors, the diagnostic criteria of malignity are cellular polymorphism and invasive growth.

Clear cell hidradenoma consists of pale or clear cells.

The tumor consists of many tiny cellular nests and ducts, containing PAS positive material. The lining is flat or two-layered. Focal keratinisation is often present. Small cellular nests are assymmetric, of tadpole shape. The tumor is usually small, limited to the upper dermis.

Intradermal tumor, consisting of small cysts (some cysts are of middle size), filled by eosinophilic debris. Two layered epithelial lining (at least focally), small papillary projections. Cuboidal cells, no squamos differentiation (no granular layer, inner surface of the cysts is uneven). No mitotic activity.

Groups of normal or enlarged sweat glands.

Fibrous stroma and ectopic breast tissue; positive reaction to estrogen receptors.

Roundish tumor, benign, often separated from surrounding dermis by a cleft. Also called mixed tumor of the skin (usually contains areas of chondroid appearance). Two forms are recognized: tubular and branching (apocrine) and form with small tubular lumina (probably eccrine). The tumor cells are CEA positive.

Apocrine variant is more common; epithelium is high, basophilic, two layered epithelium; forming duct-like and cystic structures and epithelial nests. The outer layer of the ducts is vimentin positive. Stroma contains mucin and often is of chondroid appearance. Epithelium sometimes shows decapitation secretion.

Eccrine variant consists of roundish tubules lined with single layer of epithelial cells. Stroma contains mucin; chondroid changes are less apparent than in apocrine type.

Invagination, lined in the depth with apocrine epithelium of two layers of cells with apocrine secretion. Near to the surface the lining changes into squamous epithelium. Many papillary projections extend into the lumen.

The dermis contains a dense inflammatory infilrate with many plasma cells.

Sometimes malformed follicles and sebaceous glands are found near the lesion. Vulgar verruca is sometimes present as well.

Well circumscribed, sometimes encapsulated cystic apocrine adenoma, located within the dermis. The tumor contains tubules, cysts and especially many papillary projections, covered by one row of columnar cells.

Apocrine glands, cysts and tubules; sometimes focal papillary structures; sometimes communication with the infundibula.

Nests of intraepidermal tumorous cells, originally described as intraepidermal basalioma, are now considered to be clonal seborrhoic keratosis or intraepidermal poroma (hidroacanthoma simplex).

Large, deeply infiltrating tumor, consisting of epithelial nests, ducts, glandular structures. Sometimes focal hair follicle differentiation. Mitoses are rare. Perineural spread is sometimes present.

Masses of small, regular, basophilic cells form cribriform structures and small cystic spaces filled with mucin. These spaces are lined by cuboid or flattened epithelium. Infiltrative growth, low or none mitotic activity, sometimes perineural spread.

Resembles adenoid basalioma, but shows no peripheral palisading on the periphery of the tumorous nests. The cells of adenoid cystic carcinoma are positive for carcinoembryonal antigen and S100 (basalioma cells are negative).

Infiltrative growing tumor, consisting of irregular nests of atypical cells. Focally the differentiation towards eccrine ducts is present. Variable desmoplasia.

Small groups of epithelial cells surrounded by large amounts of mucin. Small, sometimes signet ring cells.

Normal sebaceous glands not connected to any hair follicle.

The lesion consists of hyperplastic, enlarged sebaceous gland and the duct leading to the surface. Sebaceous epithelium is mature. If immature, basaloid cells are present, than they are located on the periphery of the lobules, and their number is low.

Resembles a group of enlarged sebaceous glands; immature basaloid cells are on the periphery.

Tumor with focal sebaceous differentiation; more or less mature sebaceous cells are mixed randomly with basophilic, immature sebaceous epithelia. Scattered mitoses may be present.